to allow the lens nucleus and soft matter to escape. Since the anterior
capsule becomes opaque after the removal of the lens, owing to the
multiplication of the cells in their attempt to lay down new lens
fibres, it is desirable to remove a portion of the anterior capsule from
the pupillary area. This may be performed (_a_) by means of capsule
forceps which are inserted closed, and when in position over the lens
are opened as widely as possible without entangling the iris, then
pressed down on to the anterior capsule of the lens and closed; in this
manner the portion of the capsule thus included is removed by a slight
lateral movement (Fig. 98); (_b_) by means of a cystotome, the lens
capsule being opened by a triangular or T-shaped incision over the
pupillary area; (_c_) by the point of the knife as it passes across the
anterior chamber; (_d_) by a discission needle before the section is
made. When the capsule of the lens has been opened properly the lens
nucleus is usually seen to come forward. The advantage of the capsule
forceps over the other methods is that they remove a larger portion of
the capsule and leave no tags which may become incarcerated in the
wound. On the other hand they are somewhat more difficult to use; more
pressure on the lens is required, and therefore dislocation of the lens
in its capsule may result. It is, therefore, not advisable to use them
in cases in which a fluid vitreous is suspected. If the teeth of the
forceps are not well made they will not grasp the capsule; it is
therefore always advisable to have the cystotome in readiness. The
cystotome also should be used when the anterior chamber becomes filled
with blood so that the margin of the iris cannot be seen and there is a
risk of the iris being grasped by the forceps.
[Illustration: FIG. 97. INCISION AND IRIDECTOMY IN CATARACT EXTRACTION.]
The method of opening the capsule with the point of the knife or needle
is useful in cases of extraction without iridectomy; the pupil should be
dilated before the operation.
=Fourth step.= _Delivery of the lens_ is performed by a gentle pressure,
combined with massage, on the extreme lower margin of the cornea with a
curette or spoon, until the upper margin of the lens presents in the
wound, when the pressure is gradually made upwards over the cornea until
the lens is delivered. Delivery of the lens may be prevented by--
(_a_) Imperfect opening of the capsule, which is usually the result of
using a blunt cystotome; if capsule forceps are used this difficulty
hardly ever arises.
(_b_) Too small an incision. The margin of the nucleus may present and
not be able to pass the wound. The wound must then be enlarged with the
iris scissors and the lens delivered in the ordinary way. Only by
experience can the amount of pressure required for the delivery of the
lens be gauged.
[Illustration: FIG. 98. OPENING THE CAPSULE WITH FORCEPS IN CATARACT
EXTRACTION. The forceps are inserted closed, brought in contact with the
lens, opened, and the capsule grasped between the blades and withdrawn
by a gentle side-to-side movement.]
(_c_) A sticky consistency of the cortex is not infrequently found in
cases of immature cataract. When the lens presents and cannot be
delivered readily it may be helped out by means of the cystotome plunged
into its substance, pressure being used on the cornea at the same time.
If from these or any other causes the suspensory ligament rupture and
the vitreous present in the wound, the lens should be removed with the
vectis. The vectis, which should be made of stiff steel, is passed
vertically into the incision and behind the lens nucleus by depressing
the handle; with a steady gentle pressure forwards it is then withdrawn
together with the nucleus. The forward pressure should be such as to
prevent the instrument slipping on the nucleus, for if it does so the
accident is nearly always followed by a rush of vitreous. A
Pagenstecher’s spoon may be used instead of the vectis, and is to be
preferred in cases where a small nucleus is suspected, since the latter
may slip through the loop of the vectis and fail to be delivered.
=Fifth step.= _Toilet of the wound._ After the nucleus has been
extracted, all the soft matter should be removed as far as possible by
gentle expression with the spoon. The angles of the coloboma in the iris
should be replaced by stroking it inwards on its anterior surface with
the iris spatula, paying particular attention to the angles of the wound
(Fig. 99). The spatula should also be passed throughout the extent of
the wound so as to free it from any capsule which may have prolapsed
into it. The conjunctival flap is then placed in position by stroking it
upwards with the iris spatula.
[Illustration: FIG. 99. CATARACT EXTRACTION. Replacing the iris, and any
tags of capsule which may be in the wound, with an iris spatula.]
=After-treatment.= Atropine is instilled either at the time of operation
or at the first dressing, and continued until all signs of redness of
the eye have disappeared. The patient should remain in bed for at least
ten days, both eyes being bandaged during the first four days. The eye
that has been operated on should be covered for at least two weeks;
subsequently a shade or dark glasses should be worn.
=Modifications.= The operation may be modified in various ways.
=The incision.= _The position_ of the incision has undergone many
modifications. The one described above is now in general use.
_The size_ of the incision should be increased when (_a_) a large
nucleus is expected, as in old people; (_b_) an immature cataract is to
be extracted; or (_c_) a fluid vitreous is suspected, so that the lens
may be delivered with as little pressure as possible.
=The iridectomy= may be omitted. _Extraction without iridectomy_ is
undoubtedly the ideal operation; it leaves the pupil unbroken and the
eye looking normal to external appearance. Further, the pupil reacts
more strongly to light than if an iridectomy has been performed. The
presence of the iris further prevents the prolapse of any capsule into
the wound. At the same time it is attended with considerable risk of
prolapse, which, as has been pointed out, is a very great danger to the
eye. With proper care this probably only occurs in about 5% of the
patients operated upon, but is so serious that the opinion of most
surgeons is in favour of the combined method (iridectomy and
extraction); but at the same time it is the practice of many surgeons to
omit the iridectomy under the following circumstances: first, if the
patient be young and the deformity will interfere with his getting
employment; secondly, if extraction of the lens in its capsule be
performed the unbroken circle of the iris will help to prevent the
prolapse of the vitreous which is otherwise so liable to take place.
[Illustration: FIG. 100. MCKEOWN’S IRRIGATION APPARATUS FOR WASHING OUT
THE ANTERIOR CHAMBER. The second and third terminals are the most
useful.]
Eserine (gr. ii ad ℥i) should be used to prevent prolapse of the iris
after the extraction has been performed, and should be continued once a
day until a good anterior chamber is present, which is usually in about
twelve to twenty-four hours, when atropine should be substituted. If the
iris betray any liability to prolapse after the operation, as shown by
the drawing upwards of the pupil, an iridectomy should be performed
before the patient leaves the table. In any case the eye should be
examined on the evening of the operation, and, if prolapse has occurred,
that portion of the iris should be removed. If a prolapse of the iris
occurs and is not discovered until the wound has healed, the conjunctiva
should be dissected off the surface in the form of a flap and the iris
tissue drawn out of the wound and removed, the angles caught in the scar
being freed if possible. The opening in the globe is subsequently closed
by replacing the conjunctival flap in position, or, if it has not been
possible to preserve the conjunctiva over the cicatrix, by raising a
flap from the ocular conjunctiva in the neighbourhood and stitching it
down over the opening in the globe. Not infrequently this operation is
followed by an attack of acute iritis, which usually subsides under
treatment.
_Preliminary iridectomy._ The iridectomy may be performed at a previous
operation. It has the advantages that the surgeon learns how the patient
will behave under operation, and how the eye will react to such an
operation. There is an absence of bleeding at the second operation,
which makes it easier, and there is less liability for the iris to
become adherent to the capsule. The disadvantages, which seem to
outweigh the advantages, are that there is a double chance of sepsis,
and that the patient has to submit to two operations when one is
sufficient. It is only performed by the author in cases in which there
is a tendency to increased tension in the eye due to swelling of the
lens in the early stages of the cataract. When a preliminary iridectomy
is performed a keratome may be substituted for the Graefe’s knife in
making the incision for the iridectomy, a much smaller one being
necessary.
=Delivery of the lens by irrigation.= McKeown removes the soft lens
matter by a process of irrigation into the anterior chamber, a practice
not yet much adopted, but of considerable service in removing the soft
matter after the extraction of the nucleus, especially in immature
cataract. It is also probable that the thorough removal of the soft lens
matter by this method reduces the number of cases of cyclitis following
the operation, since the soft matter forms a suitable medium for the
growth of organism. The apparatus used is shown in Fig. 100, nozzle No.
2 being the most useful; it is inserted into one angle of the wound and
a stream of sterilized normal saline solution at 39°C. (in the flask) is
allowed to flow into the anterior chamber; this stream is obtained by
raising the flask until sufficient pressure is obtained. An undine may
be substituted for the flask. Care should be taken that there is a free
return of fluid from the anterior chamber; irrigation should be
continued until as much as possible of the soft matter has been removed.
=Extraction of the lens in its capsule.= This operation is frequently
performed in India, where patients will often not return for needling of
secondary cataract (capsulotomy). Although the method undoubtedly yields
good results, the percentage of eyes damaged by loss of the vitreous
must be higher than when the posterior capsule of the lens is left
intact. The operation may be performed with or without an iridectomy,
the lens being removed by pressure on the cornea with a large strabismus
hook. If the vitreous should present, the lens should be removed with
the vectis.
Extraction of the lens in its capsule is also performed when the lens is
dislocated and causing irritation. If the lens be in the anterior
chamber immediate extraction is called for, as glaucoma is a usual
complication. Eserine is first instilled in order to contract the pupil
and prevent the lens passing back into the posterior chamber; an
incision is then made as for a cataract extraction and the lens removed
by means of the vectis. Complete dislocation of the lens into the
vitreous rarely requires operation, as the patient is able to see.
Partial dislocation (luxation) occasionally calls for extraction, the
vectis usually being employed for delivering the lens, but before
undertaking the operation an attempt should be made to get the lens into
the anterior chamber by dilating the pupil and making the patient lie
face downwards; if this is successful eserine should be instilled to
contract the pupil behind the lens and so retain it in the anterior
chamber, from whence it can more easily be extracted. Some surgeons
prefer to fix the lens with a needle passed through the sclerotic behind
the ciliary body before making the incision.
=Subconjunctival extraction.= In order to diminish the risks of sepsis,
more especially in cases in which the conjunctiva is affected with
trachoma, some continental surgeons deliver the lens into a pocket
beneath the conjunctiva, whence it is subsequently removed. The
operation has the additional advantage of a better blood-supply to the
corneal flap, which is also held in better position after the operation.
_Operation._ A section upwards is made with a Graefe’s knife as in the
ordinary method of extraction previously described, the lens capsule
being opened with the point of the knife as it is passed across the
anterior chamber. When the section through the sclerotic has been
completed and the knife lies entirely beneath the conjunctiva it is
withdrawn.
The wound in the conjunctiva on the outer side is then enlarged upwards
with scissors, and an iris spatula is passed beneath the conjunctiva
from the small wound on the inner side and the point made to appear in
the wound on the outer side; by this means the conjunctiva is raised on
the spatula, and by means of sharp-pointed scissors a pocket is made in
an upward direction by undermining the conjunctiva (Fig. 101). Delivery
of the lens is then performed into this pocket, from which it is
subsequently removed, the conjunctival wound on the outer side being
closed with a stitch. The advantage of this form of subconjunctival
extraction over other forms which have been devised is that if
difficulty is met with in delivering the lens, &c., the operation can be
readily converted into an ordinary extraction by completing the division
of the conjunctival flap.
[Illustration: FIG. 101. SUBCONJUNCTIVAL EXTRACTION. The section in the
sclerotic being completed with a Graefe’s knife, the figure shows the
method of undermining the conjunctiva to form a pocket into which the
lens is delivered and from which it is subsequently removed.]
=Complications.= These may be immediate or remote.
=Immediate.= 1. If the knife-point become entangled in the iris as it is
passed across the anterior chamber it should be slightly withdrawn, if
this can be done without loss of aqueous, the iris being thereby
disengaged.[4]
[4] For the other complications which may arise in passing a Graefe’s
knife across the anterior chamber, see Glaucoma Iridectomy, p. 222.
2. _Loss of the aqueous before the section is complete_ may result in
the entanglement of the iris as before described, or the iris, owing to
the presence of the aqueous in the posterior chamber, may bulge forward
in front of the knife-blade. The latter complication is more likely to
occur if the section be made too rapidly. The iris may sometimes be
disengaged by depressing the handle of the knife towards the patient’s
chin and raising the blade towards the cornea so as to allow the aqueous
in the posterior chamber to escape. If this cannot be accomplished, the
section should be completed and the iris, which may be divided by the
knife, removed subsequently when doing the iridectomy.
3. _Avulsion of the iris_ due to movement of the patient’s head. This is
more liable to take place if the eye has not been properly cocainized
some time before the operation. The grasping of the iris by the forceps
is always felt by the patient to a certain extent, and he should be
warned not to move. Avulsion is usually not complete and only results in
a larger iridectomy than was intended.
4. _Dislocation of the lens._ (_a_) When opening the capsule, either
from too great pressure of the capsule forceps, or from the patient
moving his head. The lens must then be delivered by the vectis. (_b_)
If, in delivering the nucleus, the upper edge is not made to present by
pressure on the lower part of the cornea, the nucleus, especially if it
be small, is liable to be dislocated upwards beyond the incision. It
must then be removed with the vectis. In cases where a small nucleus is
suspected, pressure should be made on the sclerotic above the incision
with a curette, as well as on the lower part of the cornea, so as to
make the nucleus present in the wound.
The lens may be dislocated backwards into the vitreous; if this should
happen and the lens cannot be delivered, the flap must be replaced in
position and the eye bandaged. Unfortunately this complication is
usually followed by irido-cyclitis and loss of the eye.
5. _Loss of the vitreous._ There are two chief phenomena which may
indicate that loss of vitreous is about to take place after the
extraction of the lens.
(_a_) The wound gapes unnaturally after the expulsion of the lens, and
the clear vitreous may be seen presenting in the wound in the still
unruptured hyaloid membrane.
(_b_) There may be an apparent deepening of the anterior chamber owing
to the fluid vitreous making its way forward through the ruptured
hyaloid into that cavity.
If the vitreous presents in the wound before the lens has been removed,
the latter should be delivered as rapidly as possible by the vectis, as
has previously been described.
If the vitreous be lost or one of the phenomena previously mentioned
occurs after the delivery of the lens, the speculum should be removed
from the eye and the conjunctival flap replaced in position as quickly
as possible. The eyelid is then carefully raised from the surface of
the eyeball by means of the lashes held in the finger and thumb and
carried downwards over the globe until it is in the closed position, and
a bandage is then applied.
As little manipulation as possible should be carried out when once the
vitreous has shown itself about to present, and unless the iris be
obviously in the wound no attempt should be made to replace it.
Loss of vitreous may be the result of subchoroidal hæmorrhage, which may
only make itself manifest after the patient has been put back to bed.
Loss of vitreous is frequently accompanied by hæmorrhage into the
vitreous, as is seen subsequently by the floating opacities therein. As
a rule these clear, and useful vision is obtained.
Detachment of the retina may follow loss of vitreous even months after
operation. This complication seems more liable to occur if the vitreous
which is lost in the first instance be normal and not of the fluid type.
6. _Intra-ocular hæmorrhage_ (see Glaucoma Iridectomy, p. 224).
=Remote.= 1. _Panophthalmitis_ is a result of infection of the wound. It
usually makes its appearance about the third day and must be treated by
evisceration. Occasionally the purulent material is limited to the line
of the incision or even to the anterior chamber; in the latter instance
the wound should be opened up and the anterior chamber washed out with
peroxide of hydrogen solution (10 vols. %). Microscopic examination of
the pus should be made and a vaccine prepared and administered; in two
cases so treated by the author a good recovery resulted.
2. _Escape of the aqueous beneath the conjunctiva_ usually occurs about
the third day, owing to the conjunctival wound having healed without the
opening into the globe being properly shut off. This is accompanied by
considerable pain, with chemosis and some œdema of the upper lid. It is
usually distinguishable from acute iritis by the pupil being evenly
dilated and discoloration of the iris being absent. The condition
usually subsides in three or four days, when the wound in the globe has
become shut off.
3. _Acute iritis_ not infrequently occurs after extraction. It usually
comes on about the third day and may be accompanied by hypopyon. It may
settle down under atropine, leeching, and dry heat, but may also pass on
into the more chronic form; adhesion of the iris to the capsule,
however, frequently results. More rarely the disease may not make its
appearance till two or three weeks after the operation (latent sepsis),
the patient suffering from recurring attacks of hypopyon. In these cases
in which the hypopyon persists, washing out the anterior chamber with
peroxide of hydrogen (10 vols. %) and the administration of a vaccine is
of service.
4. _Chronic irido-cyclitis_ is usually primary, but may occasionally
follow an acute attack of iritis. Of all the disastrous complications,
this is by far the worst. It may not only destroy the sight of the eye
on which the operation has been performed, but may set up sympathetic
ophthalmia in the other eye. The eye does not settle down well after the
operation, there being usually some prolapse of the iris or capsule into
the wound. It remains injected or flushes up on exposure to light. After
a time (usually about the end of the third week) keratitis punctata
makes its appearance, and the tension of the eye may become decreased or
occasionally increased. The disease may resolve or go on to shrinking of
the globe. Energetic treatment with atropine and hot fomentations
locally, with the internal administration of iron, is indicated. The
administration of staphylococcus vaccine causes only temporary
improvement in most instances. In six cases so treated by the author the
improvement was only temporary, in spite of the fact that there was a
definite local reaction to the vaccine and in two cases the
staphylococcus albus was isolated from the fluid in the anterior
chamber. If at the end of two months the eye be red and well-marked
keratitis punctata be present, and if the pupil be beginning to be drawn
up and the eye shows no tendency to improve, enucleation should be
seriously considered; this is especially advisable if the projection of
light has become defective, showing that the retina is probably
detached. If any signs of sympathetic irritation, such as mistiness of
vision, ciliary flush, or photophobia, appear in the eye which has not
been operated on, the exciting eye should be enucleated. On the other
hand, if well-marked inflammation has developed in the sympathizing eye,
which may also be cataractous, and the other eye has a fair amount of
vision, it becomes extremely questionable whether it is advisable to
enucleate the exciting eye. Every case must be judged on its own merits
according to the extent and severity of the disease. In a few cases in
which the incarceration of the capsule in the wound leads to a very
chronic cyclitis, its division with a cutting needle will sometimes lead
to subsidence of the inflammation. It is most important that every eye
that has been operated on should be examined for the presence of
keratitis punctata, especially before allowing the patient to use the
eye or before another operation is performed on it.
5. _Glaucoma_ following extraction occurs as a result of (_a_) soft lens
matter blocking the angle of the anterior chamber. As a rule the tension
will usually subside under eserine, but evacuation of the anterior
chamber (see p. 233) may have to be performed; on the whole the results
are satisfactory. (_b_) The incarceration of the capsule in the wound,
pulling forward the iris and blocking the angle of the anterior
chamber. Division of the lens capsule is usually sufficient to make the
tension subside. Failing this, sclerotomy should be performed; the
prognosis is not nearly so good when the increased tension is due to
this cause.
6. _Striate keratitis_ usually makes its appearance on the second or
third day after operation. The cornea near the line of incision presents
a grey striped appearance with the striæ arranged at right angles to the
wound. Pathologically the condition is due to an infiltration of the
deeper layers of the cornea, the striped appearance being caused by
wrinkling of Descemet’s membrane; the condition probably arises from
septic infection. As a rule the affection subsides without giving rise
to further trouble, but occasionally local suppuration and even
panophthalmitis may follow.
A grey horizontal line about the centre of the cornea is sometimes seen
after an eye has been too tightly bandaged; this always disappears when
the bandage is removed.
7. _Erythropsia_ (red vision) occasionally follows the extraction of the
lens, and is probably due to bleaching of the visual purple following
the admission to the eye of an unusual amount of light; it usually
disappears in a few weeks.
8. _Defective vision._ Glasses have to be worn after removal of the
lens. Usually patients who were previously emmetropic require about + 11
to see clearly for distance and + 15 for near vision.
The section produces some flattening of the corneal curvature at right
angles to the line of the incision; this usually amounts to about two
diopters.
COUCHING
Couching is the removal of the lens from the pupillary area by
depressing it backwards into the vitreous. It is rather a relic of the
past than a present-day operation, although it is extensively practised
by quacks in India. Under certain circumstances the operation still
seems justifiable; it is very simple, and is followed by immediate
restoration of vision, but the subsequent risks of irido-cyclitis,
retinal detachment, and glaucoma are so great, that, according to some
authorities, couching should only be undertaken in preference to
extraction when the latter operation has only a chance of one in three
of giving satisfactory vision.
=Indications.= The chief indications for its performance are:--
(i) The presence of a fluid vitreous, the patient having had the lens of
the other eye extracted with bad results.
(ii) In the insane, where it would be impossible to carry out the
after-treatment of extraction satisfactorily.
=Operation.= The operation is usually done under cocaine; in the case
of the insane a general anæsthetic is usually necessary. It has been
performed by simple depression of the lens backwards into the vitreous
with a needle passed through the cornea (anterior route). This operation
yields unsatisfactory results owing to the lens being liable to return
into the pupil; this can be partly overcome by sweeping the needle round
the periphery of the lens so as to divide the suspensory ligament, but
the operation is not so satisfactory as when the needle is passed in
from behind the ciliary body and the lens pressed down from behind
(posterior route), to which the following description applies. The
capsule of the lens should be torn freely, so that some absorption may
subsequently take place and diminish the risk of complications.
=Instruments.= Speculum, fixation forceps, needle.
_First step._ The pupil should be dilated with atropine. The patient’s
head should be well raised on the table. The needle is passed through
the sclerotic about 5 millimetres behind the limbus to the outer side.
The posterior capsule of the lens is then freely divided by a sweeping
movement.
_Second step._ The needle is next made to appear in the lower part of
the pupil by carrying it round the lower and outer border of the lens.
The anterior capsule is then freely divided.
_Third step._ The shaft of the needle is laid flat on the surface of the
lens towards its upper part, and by raising the handle of the needle the
lens is displaced backwards into the vitreous. The tearing of the
suspensory ligament on the inner side may be assisted by the cutting
edge of the needle during depression.
=Complications.= _Immediate._ Difficulty may be experienced in making
the lens lie at the bottom of the vitreous, and it is only by frequent
depression of the lens backwards and downwards, with a sweeping movement
of the needle to divide the suspensory ligament, that the desired effect
can be obtained.
_Remote._ The lens nucleus may prolapse through the pupil into the
anterior chamber. If this should happen, the patient should be placed on
his back and the pupil dilated with atropine; if the nucleus does not go
back into the vitreous chamber it should be depressed by means of a
needle passed through the cornea.
Glaucoma may result from the dislocation of the nucleus into the
anterior chamber and should be treated as described above. It may also
be present with a lens which is dislocated backwards. This condition is
very liable to end in loss of sight. Probably the only hope of relieving
the tension is by the use of eserine or the performance of a
cyclo-dialysis.
Cyclitis and retinal detachment may also follow, and usually end in
blindness.
CHAPTER III
OPERATIONS UPON THE IRIS
IRIDOTOMY
=Indications.= Iridotomy is an operation which is performed when the
iris has become drawn up after a cataract extraction, so that there is
no pupil, or the pupillary area is covered by the upper lid. A long
interval should elapse between the extraction and the iridotomy, since
these cases have usually suffered from cyclitis following the operation.
Iridotomy should not be performed for at least six months after all
signs of cyclitis have disappeared, for the frequent failure of the
operation is due to the fact that the opening made in the iris and
underlying capsule becomes filled with fibrous exudation as the result
of cyclitis, which is frequently set up again by the operation if
undertaken before a sufficient time has elapsed for the eye to settle
down after the inflammation. The ideal operation, therefore, is to make
an artificial pupil with the least amount of trauma to the ciliary body.
=Instruments.= Speculum; fixation forceps; a long, narrow, bent ‘broad
needle’; Tyrrell’s hook, iris scissors, iris forceps, and spatula.
=Operation.= Many operations have been devised for this most troublesome
condition, but the following is the one that the author has found to be
successful.
The operation is usually performed under a general anæsthetic, but this
is not essential.
_First step._ The surgeon stands facing the patient on the same side as
the eye to be operated on. The long, bent, broad cutting needle is
passed into the anterior chamber from the limbus downwards and inwards,
and is driven directly through the iris and underlying capsule. The
needle is then made to pass in an upward and outward direction behind
the iris into the pupillary area above, or if no pupil be present, again
through the iris (Fig. 102). The bent broad needle is made to cut
laterally by slightly deflecting the handle so as to produce a band of
iris and capsule; the cutting needle is then withdrawn.
_Second step._ A Tyrrell’s hook, bent to the correct angle, is passed
beneath the band (Fig. 103), which is drawn into the wound and removed
with iris scissors. A large opening is thus obtained with a minimum
amount of trauma. If the hook should slip, the band may be seized with
iris forceps, withdrawn from the wound, and removed.
=Alternative methods.= The following methods have been practised:--
=Simple incision= across the fibres of the iris by means of Graefe’s or
Knapp’s knife.
=Division with scissors= through a wound of the limbus.
By these two methods the opening produced is small, and is very liable
to be closed by the subsequent cyclitis. The following operation yields
more satisfactory results.
[Illustration: FIG. 102. IRIDOTOMY. Showing the incision with a long,
bent broad needle.]
[Illustration: FIG. 103. IRIDOTOMY. Showing the method of withdrawing
the band of iris and capsule with a Tyrrell’s hook.]
=Kuhnt’s operation.=
=Instruments.= Speculum, fixation forceps, Graefe’s knife, iris forceps
and scissors.
_First step._ The surgeon, standing facing the patient, enters the
anterior chamber about 2 millimetres inwards from the limbus at the
junction of the middle and lower third of the cornea with a Graefe’s
knife, the cutting edge directed downwards. The knife is then made to
penetrate the iris and underlying capsule, and to travel beneath this to
a similar point on the other side, where it is made to come back again
into the anterior chamber by again penetrating the iris, and finally out
again through the cornea. The knife is then made to cut out in a
downward direction.
_Second step._ Iris forceps are inserted and the flap of iris and
capsule is withdrawn and as much of it removed as possible. A more or
less triangular opening usually results.
=Ziegler’s operation.=
=Instruments.= Ziegler’s knife needle, speculum, fixation forceps.
The object of the operation is to cut a V-shaped flap in the iris and
underlying capsule, folding the flap backwards on its base so as to form
a triangular opening in the iris membrane to serve as a pupil.
_First step._ The knife needle is entered at the corneo-sclerotic
junction with the blade turned on the flat and is passed completely
across the anterior chamber to within 3 mm. of the apparent iris
periphery. The knife is then turned edge downwards, and carried 3 mm. to
the left of the vertical plane (Fig. 104).
[Illustration: FIG. 104. IRIDOTOMY BY ZIEGLER’S METHOD. Showing the
shape of the knife and the position of the first puncture in the iris;
the cutting is performed by a sawing movement.]
_Second step._ The point is now allowed to rest on the iris membrane,
and with a dart-like thrust the membrane is pierced. Then the knife is
drawn gently up and down with a saw-like motion, without making much
pressure on the tissue to be cut, until the incision has been carried
through the iris tissue from the puncture in the membrane to just
beneath the corneal puncture. This movement is made wholly in a line
with the long axis of the knife, the shank passing to and fro through
the corneal puncture, loss of the aqueous being avoided in the
manipulation (Fig. 105).
_Third step._ The pressure of the vitreous will now cause the edges of
the incision to bulge open immediately into a long oval. The knife-blade
is raised until it is above the iris membrane, and is then swung across
the anterior chamber to a corresponding point on the right of the
vertical plane. Owing to the disturbance in the relation of the parts
made by the first cut, this point is somewhat displaced and the second
puncture must be made 1 mm. further over.
_Fourth step._ With the knife-point again resting on the membrane, a
second puncture is made and the incision is carried rapidly forward by
the sawing movement to meet the extremity of the first incision at the
apex of the triangle, thus making a V-shaped cut. Care must be taken
that the pressure of the knife-edge on the tissue shall be most gentle,
and that the second incision shall terminate a trifle inside the
extremity of the first, in order that the last fibres may be severed and
thus allow the apex of the flap to fall down behind the lower part of
the iris membrane (Fig. 106). When the operation has been completed the
knife is turned on the flat and withdrawn.
IRIDECTOMY
The operation of iridectomy differs widely in its performance, according
to the different conditions for which it is used. Hence it is better to
prefix the condition for which it is employed, thus: preliminary
iridectomy, optical iridectomy, glaucoma iridectomy.
[Illustration: FIG. 105. IRIDOTOMY BY ZIEGLER’S METHOD. Showing the
first incision and the position of the second.]
[Illustration: FIG. 106. IRIDOTOMY BY ZIEGLER’S METHOD. Final step; the
triangular flap of iris attached at its base is turned downwards.]
Apart from being one of the stages of removal of a cataract, already
described, it is performed as an independent operation in the following
conditions:--
1. For optical purposes (optical iridectomy).
2. For the relief of glaucoma, primary and secondary (glaucoma
iridectomy).
3. For small growths at the free margin of the iris.
4. For prolapse of the iris through a wound.
OPTICAL IRIDECTOMY
=Indications.= Iridectomy for optical purposes is performed for a
centrally situated nebula of the cornea and in some very rare cases of
small central opacities in the lens. In the latter condition it is
rarely of much value, as nearly all the rays which enter the eye pass
through the central portion of the lens. Further, in this condition the
lens may be removed and better sight obtained with glasses. Optical
iridectomy should always be performed opposite a clear portion of the
cornea, the lower segment of the eye being chosen, otherwise the
coloboma may be subsequently covered by the upper lid. The site of
election for the operation is downwards and inwards, but in all cases
the patient should be carefully examined in the following ways: (1) the
vision is tested, any refraction being corrected without a mydriatic;
(2) the pupil is then dilated, and the best situation for the iridectomy
determined by means of a stenopaic slit. The vision must be definitely
improved by the use of these before operation can be advised. The
disadvantage of an iridectomy is that it allows more light to enter the
eye, and, if the periphery of the lens be uncovered, spherical
aberration may result. For both these reasons, therefore, it is
advisable to make the iridectomy as small as possible. Tattooing of the
central scar in the cornea will often diminish the amount of light
entering the eye, but before undertaking the latter operation, the eye
should be cocainized and the area covered with a piece of black paper to
see if the vision is improved thereby.
[Illustration: FIG. 107. OPTICAL IRIDECTOMY. The incision being made
with a keratome.]
=Instruments.= Speculum, fixation forceps, bent broad needle or small
keratome, Tyrrell’s hook, iris forceps, scissors, and spatula.
=Operation.= The operation is usually performed under cocaine.
_First step._ The eye is fixed by grasping the conjunctiva directly
opposite the spot at which the incision is to be made. The incision is
then made by means of a keratome or bent broad needle directly behind
the limbus, and enlarged laterally if desired (Fig. 107).
_Second step._ A Tyrrell’s hook, bent at the correct angle, is passed on
the flat into the anterior chamber. When the margin of the iris is
reached the handle is rotated and the hook is made to engage the free
border of the iris, which is then withdrawn from the wound; a small
portion is removed with scissors, which should be held at right angles
to the wound when dividing the iris (Fig. 108).
[Illustration: FIG. 108. OPTICAL IRIDECTOMY. Method of removing the iris
to produce a small coloboma.]
_Third step._ The iris should be carefully replaced and the pupil kept
under the influence of eserine until the anterior chamber has re-formed,
when atropine should be substituted.
Care must be taken to see that the Tyrrell’s hook presents no sharp
angle, and great care is required in its manipulation, otherwise the
lens capsule may be damaged, and traumatic cataract will result. If the
iris slips from the grasp of the Tyrrell’s hook, iris forceps should be
used, the iris being grasped near its free margin and as small a portion
as possible withdrawn.
=Brudenell Carter’s method.= The ordinary optical iridectomy divides the
sphincter iridis and so inhibits the activity of the pupil. With the
idea of obviating this, Brudenell Carter removed a small portion of the
iris (button-hole), leaving the pupillary margin intact. On the whole
the results of the latter operation are no more satisfactory, and the
operation is more dangerous to perform owing to the likelihood of
wounding the lens, and to the fact that monocular diplopia occasionally
results.
The pupil should be under the influence of eserine. The incision is made
as in the previous operation. De Wecker’s iris scissors are inserted
open into the anterior chamber, closed, and the piece of iris which
bulges up between the blades cut off; this can usually be withdrawn with
the scissors; or if not, it should be removed subsequently by forceps.
[Illustration: FIG. 109. OPTICAL IRIDECTOMY. Showing the coloboma.]
GLAUCOMA IRIDECTOMY
=Surgical and pathological anatomy.= The fluid in the anterior and
posterior chambers of the eye is secreted from the ciliary body by a
process of modified filtration. The fluid passes partly direct into the
posterior chamber and partly behind the suspensory ligament of the lens,
making its way forward into the posterior chamber through the fibres of
the suspensory ligament. From the posterior chamber it passes into the
anterior through the pupil; from the anterior it filters at the angle of
the anterior chamber through the ligamentum pectinatum into the canal of
Schlemm; thence it is carried into the blood-stream by the venous
anastomosis in that region (Fig. 110).
The essential change found in all cases of primary glaucoma is the
blocking of the angle of the anterior chamber owing to the root of the
iris being applied to the back of the cornea, and thus preventing the
filtration of the fluid into the canal of Schlemm, as a result of which
the tension of the eye is raised, either acutely (acute glaucoma) or
slowly from time to time (chronic glaucoma) (Fig. 111). The aim of every
operation for the permanent relief of glaucoma is the opening up of
Schlemm’s canal at the angle of the anterior chamber or the creation of
a new lymph channel between the anterior chamber and the
subconjunctival tissue (filtrating cicatrix). Although this latter
condition is not unattended by the risk of the spread of inflammation
from the conjunctiva to the interior of the globe, it is not an
inadvisable condition to obtain in some cases of chronic glaucoma if the
scar be small and free from iris tissue; in this disease the opening up
of the canal of Schlemm by iridectomy is often impossible. (See
Sclerectomy, p. 231.)
=Indications.= Since the days of von Graefe, who first performed
iridectomy empirically for the relief of glaucoma, the operation has
held the first place in its treatment.
(i) =In primary glaucoma.= Iridectomy should be undertaken as early as
possible in the disease. _In acute cases_, unless the tension is
relieved, the disease ends in rapid destruction of the sight. Operation
should always be undertaken as quickly as possible, provided the patient
has not lost his perception of light for longer than about ten days.
[Illustration: FIG. 110. THE NORMAL ANGLE OF THE ANTERIOR CHAMBER.
A. Cornea.
B. Ciliary processes.
C. Iris.
D. Ciliary muscle.
E. Pectinate ligament, to the right
of which is the angle of the chamber.
F. Canal of Schlemm.
G. Lens.
H. Posterior chamber.
I. Anterior chamber.
]
Whilst waiting for the operation, the pupil should be put under the
influence of eserine (2 to 4 grains to the oz.) with the idea of
reducing the tension by contraction of the pupil. Some surgeons, in
addition to using eserine, perform a posterior scleral puncture with the
idea of temporarily reducing the tension and allowing the acute symptoms
to subside, and do the iridectomy some twenty-four to forty-eight hours
later. This method is extremely useful (_a_) in cases where a general
anæsthetic is inadvisable, since the reduction of tension allows cocaine
to diffuse into the eye; (_b_) in cases liable to subsequent
intra-ocular hæmorrhage, a more gradual reduction of tension being
obtained, rupture of a choroidal vessel is less likely to occur; (_c_) a
deeper anterior chamber is often obtained, and hence there is less risk
of wounding the lens during the operation; (_d_) in cases where the
operation has been performed in one eye and the lens has been
subsequently extruded on the dressings.
_In chronic cases_ early iridectomy is desirable, since the root of the
iris applied to the posterior surface of the cornea becomes atrophic,
so that when an iridectomy is performed the iris tears off at the
anterior part of the atrophic portion, leaving the angle of the chamber
still occluded by its root (Figs. 112 and 113). It is especially in
these cases that a filtrating cicatrix, which sometimes follows
iridectomy or sclerotomy, is desirable, and indeed some surgeons
(Herbert and Lagrange, see p. 231), have recently performed operations
with this idea in view, and it is probable that this operation or
cyclo-dialysis will prove to be of use in these cases.
Operation is only contra-indicated in a few very rare cases in which the
tension is controlled by the use of eserine.
(ii) =In congenital glaucoma (bup[h]thalmos).= In this affection the
results of iridectomy vary. Without doubt, the tension has been relieved
by iridectomy in some cases, and either this operation, sclerectomy, or
cyclo-dialysis should be tried if the disease be not too far advanced.
(iii) =In secondary glaucoma.= For obvious reasons the predisposing
causes should always be taken into consideration. Thus it would be of no
use to perform an iridectomy in the case of a growth in the choroid. On
the other hand, an iridectomy would be unjustifiable for soft lens
matter in the anterior chamber, which merely requires evacuation. An
early iridectomy in cyclitis is not likely to influence the course of
the disease favourably; at the most a paracentesis is required. As the
early stages of cyclitis may give rise to tension, it is essential that
every case of glaucoma should be examined for keratitis punctata before
operation.
[Illustration: FIG. 111. THE ANGLE OF THE ANTERIOR CHAMBER FROM A CASE
OF RECENT GLAUCOMA. Showing its occlusion by the base of the iris, A,
being adherent to the posterior surface of the cornea, so preventing
filtration of the aqueous into the canal of Schlemm, B.]
In iris bombé and total posterior synechiæ an iridectomy is indicated
more to re-establish the communication between the anterior and
posterior chambers than to clear the angle, and therefore it need not be
so extensive. In cases of iris bombé where iritis is still present, and
in cases of cysts of the iris, transfixion is all that is necessary.
It is very doubtful if iridectomy in glaucoma following thrombosis of
the central vein is justifiable, for as a rule the tension is not
permanently relieved thereby. In secondary glaucoma following cataract
extraction or anterior synechiæ, division of the capsule or the anterior
synechiæ will often relieve the tension.
=Instruments.= Speculum, fixation forceps, Graefe’s knife (with a short,
stiff, narrow blade), iris forceps, scissors, and spatula.
=Operation.= With the idea of opening up the angle of the anterior
chamber by removing the iris as near its root as possible, the incision
should be made somewhat further back behind the corneo-sclerotic
junction than in cataract extraction. At the same time, if the incision
be placed too far back the ciliary body is liable to prolapse into the
wound. The old idea of opening up the canal of Schlemm by dividing it
has been abandoned, as to do so would certainly result in prolapse of
the ciliary body; and even if this did not happen, no good would result,
since the canal would become closed subsequently by cicatricial tissue.
[Illustration: FIG. 112. THE ANGLE OF THE CHAMBER IN A CASE OF CHRONIC
GLAUCOMA. The iris, A, has become atrophic at its root. An iridectomy in
this case would not free the angle of the chamber, as the iris would
separate at the point A.]
Although von Graefe used a keratome for making the incision, most
British surgeons of the present day use a Graefe’s knife, as it gives an
incision that is less shelving and more irregular, thus predisposing to
the formation of a filtrating scar; a good conjunctival flap is obtained
with it and there is less risk of wounding the lens.
When performing the iridectomy it is practically impossible to cut the
iris with scissors at its attachment to the ciliary body, and it is
better to rely on tearing it off from the ciliary body, as it is in this
situation that the iris is thinnest and most likely to give way,
provided it has not become atrophic by prolonged contact with the
cornea.
In acute cases and in cases of secondary glaucoma where there are many
adhesions a general anæsthetic is desirable.
_First step. The incision._ The position of the surgeon is as for
cataract extraction. The eye is fixed by grasping the conjunctiva close
to the limbus downwards and inwards. If the patient be under an
anæsthetic, two pairs of fixation forceps should be used, one being held
by an assistant. Occasionally in glaucoma the conjunctiva tears very
easily, and in these cases scleral forceps are of use, or, if the knife
be already in the eye, grasping the insertion of the superior or
inferior rectus. The Graefe’s knife should be directed downwards and
inwards towards the point of fixation, the point being passed through
the sclerotic 1.5 mm. behind the limbus to the outer side. Directly the
anterior chamber is entered, the handle is depressed towards the
patient’s chin. The knife-point is kept superficial to the iris and is
passed very slowly across the anterior chamber, close to its periphery
until the position of the counter-puncture is reached. The
counter-puncture should be situated about 1 mm. behind the limbus in a
direct line with the original puncture. Care must be taken in making the
counter-puncture that the knife-point does not slip back on the
sclerotic and so emerge further back in the eye than is desired. The
knife is then made to cut out upwards and a good conjunctival flap is
obtained. The incision should be carried out slowly, so that the aqueous
escapes gradually, as sudden reduction in the intra-ocular tension is
liable to lead to intra-ocular hæmorrhage.
[Illustration: FIG. 113. IRIDECTOMY FOR GLAUCOMA. Failure to relieve the
tension owing to the iris not tearing off at its junction with the
ciliary body, due to atrophy from prolonged contact with the cornea.]
_Second step. The iridectomy._ The iris forceps are inserted closed into
the anterior chamber, opened, and made to grasp the iris near the
periphery (Fig. 114) towards the side of the wound on which the iris is
first to be divided; then with a slight side-to-side movement of the
forceps the iris is withdrawn from the wound until its peripheral
attachment to the ciliary body, near where it is held by the forceps,
is felt or seen to give way (irido-dialysis) (Fig. 115). The iris is
then drawn a little further out from the wound, and one side of the
dialysis is divided with the scissors as near the scleral wound as
possible. The iris held in the forceps is then pulled over to the other
angle of the wound, and as much of it as possible is pulled out and
divided close to the scleral incision (Fig. 116). The angles of the
incision are freed from iris by means of the spatula and the
conjunctival flap is replaced in position. Both eyes are then bandaged.
=After-treatment.= The patient should be kept in bed for a week, and
during the first four days should not be allowed to raise the head from
the pillow. After that time the eye not operated upon may be uncovered;
eserine should have been instilled into it before the operation and at
subsequent dressings to prevent the possible onset of glaucoma owing to
the dilatation of the pupil which follows the application of the bandage
to the eye. It is not necessary to use any mydriatic or myotic for the
eye which has been operated upon.
[Illustration: FIG. 114. IRIDECTOMY FOR GLAUCOMA. Showing the position
in which the iris should be grasped with forceps.]
[Illustration: FIG. 115. IRIDECTOMY FOR GLAUCOMA. Showing the
irido-dialysis produced before division.]
=Complications.= These may be immediate or remote.
=Immediate.= 1. In passing a Graefe’s knife into the anterior chamber to
make the section, care must be taken that the cutting edge is directed
upwards. If by accident it should be inserted with the cutting edge
directed downwards the knife should be withdrawn and the operation
postponed for a day or two until the anterior chamber has re-formed.
Care must be taken that the cutting edge is kept on the same plane as
the upper edge of the back of the knife, otherwise the incision is
liable to pass further back than is intended.
2. _Splitting the cornea._ The anterior chamber often being little more
than a potential space, the knife may be passed between the lamellæ of
the cornea and may not enter the anterior chamber at all. The indication
that the knife-point is not in the anterior chamber is that there is no
diminished resistance, such as is usually felt when the knife enters the
chamber; if its point be slightly depressed, the cornea will be seen to
dimple in over the position of it, showing that the point is not free in
the anterior chamber.
3. _Locking of the knife._ This is due to the fact that the puncture and
counter-puncture are not made in the same plane, the knife being
twisted. It is much more liable to occur if a knife be chosen with a
blade which is not sufficiently stiff. As a rule the blade can be made
to cut out, but failing this, the knife should be withdrawn sufficiently
to allow a fresh counter-puncture to be made, or else withdrawn
altogether and the operation postponed.
[Illustration: FIG. 116. IRIDECTOMY FOR GLAUCOMA. Division of the iris
to form the inner angle of the coloboma. The iris is pulled out as far
as possible before removal.]
4. _Wound of the lens._ The great safeguard against wounding the lens is
to keep the point of the knife always superficial to the iris and in the
periphery of the anterior chamber. If the lens be definitely wounded at
the time of the operation it should be extracted immediately after the
iridectomy. If the wound be only subsequently discovered (usually about
the third or fourth day), provided the lens be not presenting in the
wound, the eye should be allowed to settle down and the traumatic
cataract extracted some time after the tenth day.
5. _Presentation of the lens in its capsule._ The lens may present in
its capsule at the time of the operation or be found subsequently on the
dressings. In the latter instance it is very liable to carry iris into
the wound, and a cystoid cicatrix results. This accident is usually due
to increased tension in the vitreous chamber; a large incision,
especially if placed rather far back in the sclerotic, will also favour
its occurrence. If the accident should happen to one eye, and acute
glaucoma be present in the other, it is advisable to do a posterior
scleral puncture before the iridectomy is performed. Partial dislocation
of the lens forward may occur after the wound has healed, leaving the
tension of the eye not reduced. This is a condition extremely difficult
to recognize, and it is usually only discovered pathologically; if
recognized clinically, extraction of the lens should be performed (Fig.
117).
6. _Intra-ocular hæmorrhage. Hæmorrhage into the anterior chamber_
occurs at the time of the operation and is readily absorbed;
occasionally it may persist for a considerable time in cases of glaucoma
of long standing.
After the operation hæmorrhage may also occur from the cut margin of the
iris, which never heals, viz. never becomes covered with endothelium.
The hæmorrhage may occur as late as two weeks after the operation and
may recur from time to time; it is especially liable to occur in old
people with arterio-sclerosis. It is usually absorbed without giving
rise to any trouble beyond delay in the convalescence.
_Retinal hæmorrhages_ are frequent and usually small, but a considerable
hæmorrhage may take place into the vitreous. As a rule these clear up
satisfactorily unless the macular region be involved.
[Illustration: FIG. 117. GLAUCOMA IRIDECTOMY. Failure to relieve the
tension owing to displacement of the lens.]
_Subchoroidal hæmorrhage._ Of all the immediate complications which
follow an intra-ocular operation this is by far the worst. The
hæmorrhage is due to the giving way of a large choroidal vessel
following the sudden reduction of tension, with the result that the
choroid and retina are stripped up from the sclerotic, and, with the
lens, may be partially extruded from the wound in the globe, from which
the hæmorrhage then proceeds. It may occur whilst the patient is still
on the operating table, or it may be discovered only after he has been
put back to bed, the blood being seen coming through the dressings.
Patients who have this condition complain of pain in the ‘corner of the
eye’ at the time of the operation. The treatment consists in
evisceration or enucleation. It is probable that limited extravasation
of blood may also occur, which need not end in disintegration of the
eye, but may cause vitreous opacity and defective vision for some weeks
after the operation.
=Remote.= 1. _The tension is not reduced by the iridectomy._ In acute
cases the prognosis with regard to the reduction of the tension and the
improvement of vision is very satisfactory. The same cannot be said of
chronic cases, especially those which have been operated on rather late
in the disease. If iridectomy, which may be repeated downwards or
extended from the previous coloboma, fail to reduce the tension, one or
more of the following measures should be adopted:--
(_a_) The use of eserine.
(_b_) Sclerotomy.
(_c_) Cyclo-dialysis.
(_d_) Sclerectomy.
(_e_) Post-scleral puncture.
It is probably in this order that they should be tried.
2. _Prolapse of the iris and irido-cyclitis_ should be treated as
already indicated under cataract extraction (see p. 208).
3. _The onset of glaucoma in the other eye_ may be induced by the
dilatation of the pupil caused by bandaging, and is best avoided by the
use of eserine. If it should occur, an iridectomy should be performed.
4. _Astigmatism_ produced by the incision is corrected with glasses.
This astigmatism is very marked, often amounting to six or eight
diopters or more.
IRIDECTOMY FOR SMALL GROWTHS OF THE IRIS
=Indications.= This is performed--
(i) As a diagnostic measure.
(ii) As a curative measure.
In the latter instance it is obvious that the growth must be very small
and situated at the free margin of the iris to yield a satisfactory
result, especially if it be of a malignant character.
=Operation.= The operation is performed under cocaine, eserine having
been previously instilled in order to contract the pupil.
_First step._ An incision should be made with a narrow Graefe’s knife in
the limbus in a position most suitable for removing the growth. The
incision should be as large as possible so as to avoid wiping off any
portions of the growth into the anterior chamber.
_Second step._ The iris should be seized well in the periphery so as to
avoid breaking up the growth; it is then withdrawn with the growth, and
the latter removed.
IRIDECTOMY FOR PROLAPSE OF THE IRIS
This operation is usually performed for prolapse of the iris following a
wound of the cornea or limbus, and may be attempted up to about the
third day after the original injury.
=Operation.= A general anæsthetic is usually desirable. The prolapsed
iris should be seized with the forceps and withdrawn from the wound. A
second pair of forceps is used to take a fresh hold on the iris, which
can usually be drawn out further (Fig. 118). It is then divided as close
to the corneal wound as possible. The iris usually flies back into the
anterior chamber clear of the corneal wound by its own elasticity, but
if it does not do so it should be freed with a spatula. The pupil should
be kept subsequently under atropine.
TRANSFIXION OF THE IRIS
=Indications.= This operation is undertaken in cases of iris bombé when
iritis is still present and when an iridectomy would subsequently lead
to a drawn-up pupil. It is also of service to evacuate the contents of
cysts of the iris (local iris bombé).
[Illustration: FIG. 118. PROLAPSE OF THE IRIS THROUGH A PUNCTURED WOUND
OF THE CORNEA. Method of withdrawing the iris by two pairs of iris
forceps before removal.]
=Instruments.= Speculum, fixation forceps, Graefe’s knife (narrow).
=Operation.= The knife is entered at the limbus from the outer side
directly opposite the occluded pupil. The apex of the iris bombé is
transfixed and the point of the knife made to appear above the pupillary
area; the iris bombé on the other side of the pupil is then transfixed
and the knife is withdrawn.
THE DIVISION OF ANTERIOR SYNECHIÆ
=Indications.= Anterior synechiæ rarely require division unless they are
likely to cause tension or the adherent iris is considered a source of
danger to the eye on account of its liability to septic infection. If
the synechiæ are causing tension, the method of division described under
sclerotomy is probably the most satisfactory; otherwise the following
method devised by Lang can be used.
=Instruments.= Speculum, fixation forceps, Lang’s knives--one with a
sharp point, and one blunt.
=Operation.= Under cocaine. The incision is made at the limbus in a
favourable situation for the division of the synechia. The sharp-pointed
knife is introduced into the anterior chamber and then rapidly withdrawn
so as not to lose the aqueous. The blunt knife is then inserted through
the incision and, partly by cutting and partly by tearing, the synechia
is divided in a direction from the periphery towards the pupil.
The operation is not at all easy to perform, since the iris gives before
the knife. Great care should be taken to avoid evacuating the aqueous,
as the operation is thereby rendered much more difficult or even
impossible.
CHAPTER IV
OPERATIONS UPON THE SCLEROTIC
ANTERIOR SCLEROTOMY
=Indications.= Sclerotomy is an operation undertaken for the relief of
increased intra-ocular tension. It is performed--
(i) Usually as a secondary operation when iridectomy has failed.
(ii) As a primary operation for the division of anterior synechiæ
causing tension.
A few surgeons prefer the operation to iridectomy, especially in cases
of bup[h]thalmos. When practised after an iridectomy which has been done
upwards, the sclerotomy is sometimes performed in a downward direction;
otherwise the section is usually made upwards. The intra-ocular tension
is probably relieved by the formation of a filtration cicatrix, and it
is therefore probable that it may be largely superseded by the
operations of cyclo-dialysis and sclerectomy.
When performed for the division of anterior synechiæ the position of the
incision should be planned according to the situation of the synechia to
be divided.
=Instruments.= Speculum, fixation forceps, Graefe’s knife with a narrow
blade.
=Operation.= The operation is done under cocaine. Eserine should have
been previously instilled in order to contract the pupil and prevent
prolapse of the iris.
Graefe’s knife should be passed across the anterior chamber in the same
manner and position as for a glaucoma iridectomy (see p. 221). In the
_complete_ method the knife is made to cut out through the sclerotic,
leaving a band of conjunctiva to hold the flap in position. In the
_incomplete_ method a band of sclerotic is left in the periphery. If the
operation is done in a downward direction, it is better for the surgeon
to stand on the opposite side of the patient to the eye on which the
operation is to be performed, operating across the patient.
=Complications.= Any of the complications which follow an iridectomy for
glaucoma may occur (see p. 222). Prolapse of the iris is probably the
most frequent.
CYCLO-DIALYSIS
=Indications.= This operation has only recently come into general use in
this country, so that statistical results have at present by no means
been worked out, but most satisfactory results have been obtained from
it in individual cases; according to German authorities about 30 per
cent. are permanently cured. Although at present its performance is
largely limited to blind eyes and to eyes that have undergone previous
operations for glaucoma, it is probable that it may come into further
use as a primary operation in the treatment of chronic glaucoma and
bup[h]thalmos. It is also of service in cases of dislocation of the lens
backwards, associated with increased tension, where iridectomy would
certainly be followed by loss of the vitreous.
[Illustration: FIG. 119. CYCLO-DIALYSIS OPERATION. Showing the method of
commencing the incision in the sclerotic; it is subsequently deepened
with the point of the knife. The dotted lines mark the incision for
turning forward the conjunctival flap.]
The operation has for its object the separation of the ligamentum
pectinatum from its attachment to the sclerotic, with the probable
result that the ciliary body and iris root become retracted by the
ciliary muscle, so that the canal of Schlemm is opened up and again
communicates with the anterior chamber. It also opens up a free
communication between the anterior chamber and the suprachoroidal
lymph-spaces. The reduction of tension is often not fully manifest for
about ten days after the operation.
=Instruments.= Speculum, fixation forceps, Graefe’s knife, fine pair of
straight iris forceps, fine pair of sharp-pointed straight scissors,
iris spatula.
=Operation.= The operation is best performed under a general anæsthetic,
as it is attended with considerable pain, although cocaine and adrenalin
are frequently used and are always advisable, since the hæmorrhage from
the scleral vessels renders it difficult to gauge the depth of the wound
in the sclerotic.
[Illustration: FIG. 120. CYCLO-DIALYSIS OPERATION. Showing the spatula
separating the ciliary body and ligamentum pectinatum from the
sclerotic.]
_First step._ By means of the straight iris forceps and sharp-pointed
scissors a semilunar conjunctival flap is first raised over the site for
the scleral incision. The incision in the sclerotic should be situated
about 5 mm. behind the corneo-sclerotic junction over the ciliary
region, the outer and upper quadrant of the eye being the easiest
position for subsequent manipulation (Fig. 119).
_Second step._ With a Graefe’s knife the fibres of the sclerotic are
carefully divided in an oblique direction forward until the
suprachoroidal lymph-space is opened for about 3 mm. The first part of
the incision is performed with the blade and completed with the point
of the knife, the anterior flap of sclerotic being held forward by
straight iris forceps. Heine uses a keratome, dividing the fibres of the
sclerotic with the point by stroking it along the line of the incision.
The depth of the incision should be carefully gauged from time to time
with the iris spatula; the pigment of the ciliary body is usually seen
in the bottom of the wound when the sclerotic has been penetrated.
_Third step._ The iris spatula is directed forwards and inserted between
the sclerotic and the ciliary body, keeping close to the former. With a
gentle side-to-side movement the spatula is made to separate the ciliary
body from the sclerotic for about one-eighth of its whole circumference;
then the ligamentum pectinatum is detached from the sclerotic for about
the same distance by gently passing the spatula forwards and making the
latter appear in the anterior chamber (Fig. 120). If it be desired to
evacuate the anterior chamber, the spatula is slightly rotated so as to
allow the escape of the aqueous. As a rule this is not necessary or even
advisable. The spatula is then withdrawn and the conjunctival flap is
replaced in position. Eserine should be instilled.
=Complications.= (1) Unless the incision be carried carefully through
the sclerotic, or the manipulations with the iris spatula be very
gentle, loss of vitreous is liable to take place. As a rule, this, if
not great, is of little consequence. (2) In passing the iris spatula
forward to separate the ligamentum pectinatum the point may pass between
the layers of the cornea; this is recognized in the resistance offered
to the side-to-side movement of the spatula, which should be withdrawn
slightly and the point depressed so as to engage the ligamentum
pectinatum. (3) Subchoroidal hæmorrhage has been known to occur after
the operation.
SCLERECTOMY
The object of the operation is the production of a filtration cicatrix
free from iris tissue for the relief of intra-ocular tension in chronic
glaucoma.
=Instruments.= As for glaucoma iridectomy, with the addition of a small
curved pair of scissors.
=Operation.= Under cocaine.
_First step._ The incision is performed as for glaucoma iridectomy (see
p. 221), except that the incision should be rather smaller and should be
carried more obliquely through the sclerotic, so that a long scleral
flap is obtained. A large conjunctival flap is very essential to cover
the wound.
_Second step._ An iridectomy is usually performed as for glaucoma; this
may be omitted.
_Third step._ After all the bleeding has ceased, the conjunctival flap
is turned forwards on to the cornea so as to expose the scleral flap;
with small curved scissors made for the purpose, an elliptical portion
is removed from the sclerotic by a single snip (Figs. 121 and 122), and
the conjunctival flap is replaced in position. As a result, a hole is
made into the anterior chamber, which thus communicates with the
subconjunctival tissue, which is bulged forwards in the form of a clear
vesicle by the escaping aqueous when the wound has healed.
[Illustration: FIG. 121. LAGRANGE OPERATION FOR THE PRODUCTION OF A
CYSTOID SCAR IN CHRONIC GLAUCOMA. Showing the method of removing a piece
of the sclerotic.]
[Illustration: FIG. 122. LAGRANGE OPERATION FOR CHRONIC GLAUCOMA.
Showing the piece of sclerotic removed by the scissors (black lines).]
The immediate results of this operation are satisfactory provided that
enough sclerotic be removed to produce a filtration cicatrix. As yet
sufficient time has not elapsed for any statistical results to be
obtained, but the cases in which the operation has been performed are
reported as satisfactory.
POSTERIOR SCLEROTOMY
=Indications.= Posterior scleral puncture is performed--
(i) For the relief of tension, the indications for which have already
been described under the indications for iridectomy in glaucoma (see p.
218).
(ii) For the evacuation of fluid behind a detached retina.
The operation in the latter instance, although not yielding very
satisfactory results with regard to the reattachment of the retina, may
be carried out with some hope of success in certain cases. Before
performing the operation the pathological cause of the detachment
should be carefully investigated, for it is obvious that it would be
useless to perform the operation in a case of detachment due to a
choroidal tumour or if definite bands of fibrous tissue could be seen in
the vitreous pulling off the retina. Undoubtedly it should be undertaken
as soon as possible after the detachment has occurred and the puncture
should enter the space filled with subretinal fluid. Whether the
puncture should penetrate the overlying retina is still a disputed
point.
After the operation a pressure bandage should be applied and the patient
should be kept on his back and not allowed to raise his head from the
pillow for at least three weeks. This latter part of the treatment is
most essential; indeed as good results may be obtained with complete
rest as by performing scleral puncture. Unfortunately, recurrence is
very liable to take place whichever method be used, even if reattachment
of the retina be obtained.
=Instruments.= Speculum, fixation forceps, Graefe’s knife.
=Operation.= Under cocaine. If no special position be indicated the
puncture is best made upwards and inwards. The patient is made to look
outwards and downwards. The conjunctiva over the sclerotic, well behind
the ciliary body, is drawn down so that when released it shall form a
valvular opening to the scleral wound. The Graefe’s knife is driven
through the conjunctiva and sclerotic, the incision being made
antero-posteriorly in the direction of the fibres of the sclerotic to
avoid wounding the choroidal vessels. It is probably better to enlarge
the wound when withdrawing the knife than to turn the latter at right
angles before it is withdrawn, as has been recommended by some surgeons.
A bead of vitreous usually escapes under the conjunctiva. If the tension
be not lowered, gentle massage of the globe through the lid should be
employed.
PARACENTESIS OF THE ANTERIOR CHAMBER
=Indications.= Evacuation of the contents of the anterior chamber is
performed for several conditions:--
(i) To reduce the tension of the eye when due to an altered consistency
of the aqueous, as for instance in cyclitis.
(ii) To evacuate pus from the anterior chamber following metastatic
infection.
(iii) To evacuate the anterior chamber in bad corneal ulceration,
especially when associated with hypopyon and tension.
(iv) To examine the aqueous for organisms in cases of cyclitis following
operation or of metastatic origin.
(v) To evacuate soft lens matter (see p. 194).
The operation is usually performed through an incision directly behind
the limbus. In the case of corneal ulceration it is sometimes performed
by dividing the base of the ulcer with a Graefe’s knife (Sämisch’s
section). When collecting the aqueous for bacteriological examination, a
sterile hollow needle with a point similar to a discission needle,
attached to a hypodermic syringe, should be passed into the anterior
chamber at the limbus and the fluid withdrawn into the syringe by an
assistant (Fig. 123). The spot through which the needle is passed is
first touched with the electro-cautery to ensure asepsis.
=Instruments.= Speculum, fixation forceps, bent broad needle, iris
spatula.
=Operation.= Under cocaine. The puncture is usually made upwards and
outwards unless there be some other special indication for its position,
such as a mass of pus in the lower angle of the anterior chamber. The
eye is fixed opposite the spot at which the puncture is to be made, and
the bent broad needle is passed into the anterior chamber through an
incision directly behind the limbus. The needle is then withdrawn and is
usually followed by a rush of aqueous. The remainder of the aqueous is
then evacuated by pressing the lower margin of the wound with an iris
spatula. In some cases where a very tenacious hypopyon is present it may
be withdrawn with the iris forceps. The only complication liable to
occur is prolapse of the iris into the wound, which should be replaced
with the spatula, or failing that, removed.
[Illustration: FIG. 123. HOLLOW NEEDLE USED FOR PARACENTESIS OF THE
ANTERIOR CHAMBER. This is used when it is desired to examine the aqueous
bacteriologically. Care should be taken to see that the cutting blade is
sufficiently wide to take the shaft of the needle.]
OPERATIONS FOR PENETRATING WOUNDS OF THE GLOBE
=Indications.= Of all the conditions which a surgeon is called upon to
see, penetrating wounds of the globe may present the most difficult
problems as to treatment. The most important factors in their treatment
and prognosis are--
1. _The time at which the patient presents himself for treatment_ and
the condition of the wound are all-important in the prognosis. Thus in
the case of a wound which is obviously septic and going to terminate in
panophthalmitis the eye should be eviscerated.
2. _The position and extent of the wound._ Formerly it was taught that
if the ciliary body were wounded the eye should be excised. The reason
for this was that these injuries were so frequently followed by
sympathetic ophthalmia owing to prolapse of the iris and ciliary body.
It is now generally recognized that sympathetic ophthalmia only follows
if the wound becomes septic, irido-cyclitis with keratitis punctata
being present, and it is only after the latter symptom manifests itself
that the eye should be excised, provided that the wound be not so
extensive as to preclude all chance of recovery from the outset.
_In wounds of the sclerotic_ all portions of the uveal tract and
vitreous which prolapse should be removed, and the wound closed with
sutures passed through the superficial episcleral tissue. Unless the
wound be small the prognosis is not good, as it is liable to be followed
by irido-cyclitis, or, if this does not occur, detachment of the retina
may ensue, following on organization of the exudates in the vitreous.
_Wounds of the cornea_ usually result in prolapse of the iris, which
should be removed in the manner described under iridectomy (see p. 208).
3. _If the lens be injured._ Unless the wound amounts to little more
than a punctured wound of the globe involving the lens, the prognosis is
bad. The wound in the lens capsule and the breaking up of the lens mean
the presence of soft matter in the anterior chamber--a condition which
favours sepsis and is liable to produce increased tension from blocking
the angle of the chamber. In patients under thirty the pupil should be
dilated with atropine and the lens allowed to absorb--assisted at a
later date by needling, when the eye has entirely settled down after the
original injury. If the patient be over thirty it is often extremely
difficult to decide whether extraction of the lens should be undertaken
at the time of the injury or at a later date. The results of both
procedures are very unsatisfactory, and the surgeon should be guided
partly by the position and extent of the wound. Given these in a fairly
favourable position, it is probable that immediate extraction will give
the best result.
4. _If the eye contain a foreign body._ Usually these are pieces of
metal or glass. The following points should be investigated to determine
whether the foreign body be in the eye:--
(i) The history of these accidents is usually the same. The patient is
chipping with a hammer and chisel, and a piece flies off and strikes the
globe. In the case of glass it is usually a mineral-water bottle which
bursts.
(ii) The position and nature of the wound in the cornea and sclerotic.
(iii) The condition of the anterior chamber--whether evacuated or not.
(iv) The tension of the eye, which may be lowered.
(v) The presence of a hole in the iris.
(vi) The presence of traumatic cataract.
(vii) Whether the foreign body is visible with the ophthalmoscope or by
focal illumination.
(viii) The localization of the foreign body by the X-rays. The latter is
the most important factor of all, since the foreign body may pass right
through the globe and be embedded in the orbit.
[Illustration: FIG. 124. AUTHOR’S CHAIR FOR THE LOCALIZATION OF FOREIGN
BODIES IN THE EYE BY THE X-RAYS. A is a rifle sight for centring the
anode, C, on the cross wire, B, behind which the photographic plate is
subsequently placed. P is the screw clamping the head-piece on to the
patient’s head. Q is the screw for regulating the height of the tube and
the distance from the patient. R is the screw for regulating the height
of the head-piece. The inset shows the arm carrying the tube more highly
magnified. E is the sliding arm carrying the tube for lateral
displacement marked for stereoscopic photographs. F is the pointer for
marking the position of the anode. D is the screw for clamping when in
position.]
=Operative treatment.= If the injury be a recent one and the foreign
body a metal of magnetizable properties, it is best removed by an
electro-magnet after localization by the X-rays (Fig. 124). Sideroscopes
have been used, but are not so satisfactory. If the foreign body be
non-magnetizable, such as a piece of copper cap or manganese steel, an
attempt may be made to remove it with forceps after localization. If
the foreign body be embedded in the lens it is often advisable to
extract the lens together with it. If the foreign body be of glass, and
it be only small, it is usually best left alone, unless capable of easy
removal, _e.g._ if it be situated in the anterior chamber; the eye will
often tolerate the presence of glass provided it be aseptic.
_The eye should be removed_--
(i) If the wound be obviously septic.
(ii) If the wound be very large, more especially if the lens be injured.
(iii) If the foreign body be a large piece of metal and cannot be
extracted.
(iv) If the eye does not settle down after one of the operations
described below, especially if irido-cyclitis with keratitis punctata
should have supervened.
=If the injury be of long standing.= It is of little use as a rule
attempting to extract a foreign body from the eye after three days,
unless it be loose in the vitreous or embedded in the lens, as it
becomes surrounded by lymph. Under these circumstances it is better to
leave it alone, or, if it be causing signs of irritation, to enucleate
the eye.
ELECTRO-MAGNET OPERATIONS
Magnets for the removal of magnetizable foreign bodies from the eye are
of two types--(1) a small magnet, which is inserted into the globe, (2)
a giant magnet, which is used to attract the foreign body in the eye
from the outside.
Surgeons differ as to which is the best method to employ. The
statistical results of both are about the same. Many surgeons in this
country, and with them the author, prefer the small magnet, especially
of the recent more powerful type (Hirschberg), which runs off the main
electric current, for the following reasons: it is more accurate (after
localization by the X-rays), there is less trauma to the globe involved,
it is more portable, and, when the foreign body is in the anterior or
the posterior chamber, it is much easier to extract it with a small
magnet than with a large one.
=With the small magnet. Instruments.= Beer’s knife, fixation forceps,
magnet (Fig. 125), and suture. The points of the magnet, which are
detachable, are sterilized by boiling.
=Operation.= The foreign body is first localized accurately by means of
the X-rays. If it lies near the wound of entrance the magnet point is
inserted, the electric circuit completed, and the foreign body
withdrawn, the wound of entrance being enlarged if necessary. If the
foreign body lies at some distance from the wound, as for instance in
the vitreous, an antero-posterior incision is made in the sclerotic, as
near to it as possible, by plunging the knife through the conjunctiva
and the sclerotic, the former having previously been drawn to one side
so as to form a valvular opening. The size of the incision should be
such that it will admit the point of the magnet and allow the foreign
body to come out, the size of the foreign body being judged by the X-ray
photograph. After the knife has been withdrawn, the point of the
electro-magnet is inserted and the circuit closed, the magnet being
withdrawn with the foreign body attached to it. The conjunctival wound
is closed by a suture if necessary. If the foreign body be situated in
the anterior or posterior chamber or the lens, an incision should be
made into the anterior chamber with a keratome, the point of the magnet
inserted, and the foreign body withdrawn. In cases in which the foreign
body is deeply embedded in the lens, more especially in patients over
thirty years of age, extraction of the lens together with the foreign
body should be performed.
[Illustration: FIG. 125. SMALL ELECTRO-MAGNET FOR EXTRACTING PIECES OF
STEEL FROM THE EYE. It is made to work direct off the electric main.]
=Complications.= _Immediate._ Failure to extract the foreign body may
arise from--
1. The foreign body being embedded in lymph. It is therefore of the
utmost importance that the operation should be performed as soon as
possible after the injury.
2. The foreign body being deeply embedded in the sclerotic so that the
magnet will not exert sufficient traction to withdraw it.
3. The foreign body being non-magnetic (all steel is not magnetic).
4. Too small a wound being made for its extraction, the metal being
wiped off on the edges of the wound as the magnet is withdrawn.
5. Insufficient power in the magnet.
_Remote._ 1. Panophthalmitis, which must be treated by evisceration.
2. Irido-cyclitis; if this be prolonged, and keratitis punctata appear,
enucleation should be performed.
3. Traumatic cataract; this may subsequently require needling.
4. Detached retina as the result of organization in the vitreous; this
may occur months after the original injury.
=With the giant magnet.= The foreign body should have been previously
localized by the X-rays, and its position and size determined, so that
it may be removed by the shortest possible route and with the least
amount of injury to the eye.
=Instruments.= Giant magnet (Fig. 126), steel spatula. (Watches and
magnetizable metal should be removed from both the patient and the
surgeon.)
=Operation.= Under atropine and cocaine. The patient is at first seated
in a chair some three feet in front of the magnet, the eyelids being
held apart by the surgeon; the electric circuit is closed. The patient’s
head is next gradually advanced towards the magnet. If a foreign body be
present in the eye and be magnetizable, the patient will usually
withdraw his head or cry out with pain, and the foreign body may be seen
bulging forward the iris from the posterior chamber. From this position
it may be removed by manipulating the head and eye in relation to the
magnet so as to withdraw it into the anterior chamber, from whence it is
removed through the entrance wound or an incision at the limbus either
by the giant magnet directly applied to the wound or by magnetizing a
steel spatula which is inserted into the anterior chamber and connected
with the magnet by a flexible steel cable. The small magnet previously
described may be used, or the foreign body removed by means of iris
forceps.
[Illustration: FIG. 126. LARGE ELECTRO-MAGNET. The current is turned on
by means of the foot pedal.]
A piece of steel in the vitreous always travels round the posterior
surface of the lens and through the suspensory ligament, and does not
injure the lens capsule.
=Complications.= These are similar to those described under the small
magnet operation.
CHAPTER V
OPERATIONS UPON THE CORNEA AND CONJUNCTIVA
OPERATIONS UPON THE CORNEA
REMOVAL OF A FOREIGN BODY FROM THE CORNEA
Removal of a foreign body from the cornea requires a good light (focal
illumination). The use of a binocular lens is also of service. Foreign
bodies lodged on the surface of the cornea can be removed easily under
cocaine with a spud. If the foreign body be deeply embedded in the
cornea a fine sterile discission needle should be used. When a foreign
body, such as a chip of iron, is deeply embedded, the needle should be
inserted slightly to one side of the entrance wound and passed beneath
the foreign body so as to lift it from its bed. When the foreign body
has partially penetrated the anterior chamber but still lies in the
cornea, an incision should be made with a keratome at the limbus and the
foreign body pushed back through the entrance wound with the aid of an
iris spatula. If the foreign body be iron, the electro-magnet may be of
use, and in this case should be tried before resorting to an incision in
the anterior chamber. A stain is left frequently after the removal of
foreign bodies; this should be removed as far as possible. Subsequently
the eye should be bandaged for a few days and bathed with boric lotion.
Atropine should be instilled if there be any signs of infiltration
around the wound.
CAUTERIZATION OF THE CORNEA
Either a chemical or the actual cautery may be used.
=Indications.= _Corneal ulceration._ The cornea being extremely dense,
organisms do not penetrate very deeply into its substance, so that
destruction of the bacteria is effected by cauterization of the
spreading portion of an ulcer; the albumin is also coagulated and so a
barrier is presented to their advance.
=Operation.= The eye is thoroughly cocainized, and the spreading portion
of the ulcer is first defined by staining with fluorescine, washing away
the excess of stain with boric lotion.
_By a chemical caustic._ Liquefied carbolic (carbolic acid crystals
liquefied in 10 per cent. of water) is applied upon a sharpened match.
Any excess should be removed so as to prevent its running on to the
cornea. A speculum is inserted and the cornea is dried by blotting with
cigarette paper; the stained area is lightly touched with the point of
the stick, particular attention being paid to the spreading margin. A
dense white plaque is the result; this usually clears up in a few days.
Atropine ointment is applied daily to the conjunctival sac.
[Illustration: FIG. 127. ELECTRO-CAUTERY.]
_By the actual cautery._ The electro-cautery (Fig. 127) point should be
extremely fine and only raised to a dull red heat. The stained area
should be touched lightly with the point.
The actual cautery is best for serpiginous corneal ulcers, carbolic acid
being more satisfactory for those of the vesicular type.
OPERATIONS FOR CONICAL CORNEA
=Indications.= Since the operation for conical cornea is not without
serious risks, it should only be undertaken when the vision cannot be
improved with glasses to 6/18; high + or - cylinders will often yield
satisfactory results. The object of all forms of operation is the
flattening of the cone.
=Operation.= This may be carried out either by excision of the apex of
the cone or by cauterization.
=Excision of the apex of the cone= is probably the more satisfactory
method, although it is somewhat more difficult to perform. The object of
the operation is to remove an elliptical portion of the whole thickness
of the cornea from the apex of the cone, the long axis of the ellipse
being placed horizontally. It leaves the eye with only a minute scar as
compared with the nebula produced by the cautery, which is often so
great as to require an optical iridectomy to restore vision.
=Instruments.= Speculum, fixation forceps, a narrow Graefe’s knife,
straight iris forceps, and scissors.
The operation is done under cocaine, atropine having been previously
instilled.
_First step._ The apex of the cone is transfixed by the Graefe’s knife
with the blade directed slightly upwards and forwards, the knife being
made to cut out. The cornea in this situation is extremely thin, being
often not more than 1 mm. in thickness. The length of the incision
should not exceed 2 mm.
_Second step._ The flap of corneal tissue thus made is seized with the
straight iris forceps and removed with iris scissors, producing a small
elliptical opening. The chief difficulty of the operation is the seizing
of the corneal flap, which is most difficult to hold; care must be taken
not to injure the lens capsule with the iris forceps or scissors when
the cornea has collapsed as the result of the evacuation of the anterior
chamber. The eye should be firmly bandaged subsequently, and the patient
kept in bed until the anterior chamber has re-formed.
=Complications.= _Slow re-formation of the anterior chamber._ The
anterior chamber will often take two or three weeks to re-form, owing to
the hole in the cornea not closing. During this time the eye is open to
septic infection and therefore the greatest care should be taken to keep
it aseptic when dressing it. For this reason and also because the
following complications are due to the same cause, it is desirable to
remove as little corneal tissue as possible in performing the operation.
It is probable that conjunctivoplasty (see p. 245) would considerably
facilitate the rapid closure of the wound.
_Anterior polar cataract_ may result from prolonged contact of the lens
with the wound in the cornea. As a rule this seldom interferes much with
vision.
_Anterior synechiæ_ from incarceration of the iris in the wound
occasionally result and may require subsequent division.
_Acute glaucoma_ is by no means an infrequent complication--indeed the
author has seen four successive cases of conical cornea, operated on
both by excision and by the cautery, followed by this complication. It
is probably due to adhesion of the root of the iris to the back of the
cornea during the time the anterior chamber is empty. It can usually be
relieved by an iridectomy.
=The electro-cautery operation.= The operation generally adopted is
known as the target operation. It consists in surrounding the apex of
the cone with two rings of cautery marks, the outer made at a dull red
heat, the inner with the point slightly brighter, whilst the apex is
cauterized at a red heat, so that rings of different depth are obtained.
Cauterization of the apex should stop just short of perforation, the
inner ring being deeper than the outer. With this method secondary
glaucoma and anterior synechiæ are not so liable to occur. On the other
hand, an optical iridectomy has to be performed more frequently. A few
surgeons still cauterize the apex of the cone until a perforation is
produced. This latter operation seems to have the disadvantages of both
methods and the advantages of neither.
REMOVAL OF TUMOURS INVOLVING THE CORNEA
Tumours which involve the cornea are usually secondary to tumours
occurring at the limbus. The chief of these are: _simple_--dermoid
patches, moles of the limbus; _malignant_--sarcoma, endothelioma,
epithelioma. Dermoid patches should be shaved off as close to the cornea
as possible; the white area left after their removal can be improved by
tattooing.
Malignant tumours in very early stages may be removed locally with
scissors and forceps, the cautery being applied to their base, since
they do not tend to invade the sclerotic deeply.
TATTOOING THE CORNEA
=Indications.= (i) To do away with the blinding effects of light through
a scar after iridectomy has been performed (see p. 215).
(ii) To simulate a pupil on a white scarred cornea.
[Illustration: FIG. 128. TATTOOING NEEDLES.]
The operation is not without risks, as it may light up old inflammation
in a previously quiet eye. Panophthalmitis and sympathetic ophthalmia
have both been known to follow it. The pricking of the needle may carry
in epithelium and implantation dermoids may arise.
=Instruments.= A fine single needle is generally used, occasionally a
bundle of needles (Fig. 128).
=Operation.= Under cocaine. Chinese ink, sterilized and prepared by
rubbing up with 1-6,000 perchloride of mercury, is smeared over the area
to be tattooed. Multiple punctures in an oblique direction are then made
into the cornea over the area desired. More paste is then rubbed in over
this area. The cornea should be intensely black after the operation, as
a certain amount of the ink is carried away by phagocytosis and shedding
of the epithelium. Subsequent reaction may be reduced by means of an
iced compress. Atropine should be instilled.
SCRAPING CALCAREOUS FILMS
Calcareous films, when not associated with active irido-cyclitis, may be
removed with advantage to the vision. Care should be taken to see that
no keratitis punctata is present before the operation is undertaken.
=Instruments.= Speculum, fixation forceps, a spoon which should have
rather a blunt edge.
=Operation.= Under cocaine. The area is very lightly scraped with the
spoon. The calcareous changes are in the deeper layers of the epithelium
and Bowman’s membrane and hence are easily removed. The scraping should
be carried well beyond the apparent margin of the film. The epithelium
often takes some time to regenerate. As a rule the results are
satisfactory, although the film is apt to recur in the course of years,
but it may be removed again if necessary.
OPERATIONS UPON THE CONJUNCTIVA
THE REMOVAL OF FOREIGN BODIES
Foreign bodies lodged in the conjunctival sac, unless embedded in the
conjunctiva, are usually found by the surgeon under the upper lid, the
sulcus subtarsalis being a favourite situation. They are easily removed
with a spud or needle, after the instillation of a drop of 4% cocaine
solution. Subsequently the eye should be bandaged for a few hours until
the effect of the cocaine has passed off, as in wiping the eye the
patient may wipe off the epithelium of the cornea whilst it is
insensitive from the cocaine.
_In order to evert the upper lid_ the patient is made to look strongly
down, the eyelashes are seized between the thumb and forefinger of the
left hand, the skin of the upper lid is pushed down above the tarsal
cartilage with the thumb of the right hand, and the lid is everted by
pulling it upwards against the point of the thumb.
OPERATION FOR PTERYGIUM
=Indications.= Pterygium should be removed when advancing across the
cornea, especially when the pupillary area is becoming involved. The
operation of ablation is the one now generally in use.
=Instruments.= Speculum, straight iris forceps, small sharp-pointed
scissors.
=Operation.= Under adrenalin and cocaine the neck of the pterygium is
seized with the forceps and the body and neck are carefully dissected
from the conjunctiva. The body and neck should be very carefully
separated right up to the corneal margin by means of forceps and
scissors. The head is then stripped off the cornea with a sharp pull.
The wound in the conjunctiva should be subsequently closed with fine
sutures, otherwise the disease will certainly recur. In stripping the
head from the cornea some of the epithelium may be torn off with it.
This usually regenerates without impairing the vision.
EXPRESSION
This is an operation for the removal of follicular formations in the
conjunctiva, and is used more especially in trachoma.
=Instruments.= Graddy’s forceps (Fig. 129), fixation forceps.
=Operation.= The operation may be performed under cocaine and adrenalin,
a little solid cocaine being rubbed into the area to be expressed. In
severe cases in which both eyes are affected, and in small children, a
general anæsthetic may be necessary.
Although a number of instruments are in use, perhaps the best, and
certainly the least painful, is Graddy’s forceps. In the case of the
upper lid it is everted, one blade of the forceps being passed into the
fornix, the other being placed over the upper surface of the everted
lid. A gentle steady pressure is applied, and the lid is drawn out
between the blades. In this way as much of the conjunctiva is gone over
as is necessary. The lower fornix is best expressed by picking up the
loose fold of the fornix with ordinary forceps and then expressing with
Graddy’s.
[Illustration: FIG. 129. GRADDY’S FORCEPS.]
If only one or two follicles be present they can be picked up with the
ordinary fine dissecting forceps and expressed, but when situated on the
tarsus the follicles are best enucleated with a spud; a solution of 1 in
50 perchloride of mercury in glycerine is then rubbed into the
conjunctiva. The operation may have to be repeated several times as new
follicles form.
CONJUNCTIVOPLASTY
Conjunctivoplasty is an operation for the transplantation of a flap of
conjunctiva to cover some loss of substance or defect in the continuity
of the globe.
=Indications.= The operation may be necessary--
(i) To close large recent wounds of the cornea.
(ii) To close the wound made by the excision of a cystoid scar.
(iii) To facilitate the healing of a clean ulcer such as Mooren’s ulcer,
or to cover the aperture made by an ulcer that has perforated.
(iv) In the treatment of conical cornea by excision of the apex of the
cone, it might facilitate the rapid closure of the wound and assist in
flattening of the cornea.
=Operation.= _First method._ Under cocaine. A flap of conjunctiva is
raised from around the limbus, having its base as near the area to be
covered as possible; its breadth should be one and a half times the
width of the area to be covered. This flap is drawn across the defect in
the cornea and stitched to the conjunctiva on the other side; the wound
made in raising the flap should be allowed to heal by granulation.
The stitches holding the flap in position cut through in two or three
days, but by that time their purpose will have been served. If the flap
be still adherent to the wound its base may be divided and any
superfluous tissue removed; the remainder will disappear rapidly.
_Second method._ The conjunctiva is dissected up all round the cornea as
close to the limbus as possible, and backwards as far as the insertion
of the recti. A purse-string suture is then inserted around its margins
and drawn tight so that the whole cornea is covered by conjunctiva. The
operation is suitable for cases in which large areas have to be covered.
REMOVAL OF TARSAL CYSTS
The Meibomian glands being embedded in the tarsal plate, cysts in them
present both on the conjunctival surface and towards the skin, but the
contents are always evacuated from the former.
=Instruments.= Walton’s iris knife, sharp spoon.
=Operation.= Under adrenalin and cocaine. The eyelid is everted and a
drop of the solution is injected into the cyst with a hypodermic
syringe. A vertical stab is made into the cyst with the knife and the
contents are then evacuated with a sharp spoon.
Difficulty may arise in fixing the cyst whilst making the incision; this
is best obviated by holding the everted lid between the finger and
thumb.
In some cases, when the cyst has persisted for a considerable time, the
sac-wall becomes so thickened that it has to be dissected out before the
mass in the lid will disappear.
CHAPTER VI
OPERATIONS UPON THE EXTRA-OCULAR MUSCLES
SQUINT OPERATIONS
=Indications.= Operations upon eyes with concomitant squint are
undertaken for two purposes:--
(i) For cosmetic reasons, to remedy a deformity due to a squinting eye
which is amblyopic.
(ii) To rectify the muscular equilibrium in alternating or latent
squints, so that binocular vision may be regained.
When the operation is performed for the latter reason the adjustment
will naturally have to be much more accurate than for the former, so as
to bring about the superimposition of the images falling on each macula.
The muscular balance is interfered with by the administration of a
general anæsthetic, and therefore the results cannot be gauged
accurately. Thus it is desirable that operations upon the ocular muscles
should be performed under local anæsthesia. This is usually possible,
except in the case of very small children.
During and after the operation muscular equilibrium is tested by means
of an electric light fixed to the ceiling immediately over the head of
the patient (see Fig. 74). The room is darkened and the patient is made
to look at the light. In a case with an amblyopic eye the reflection of
the light should appear in the middle of each cornea if the eye be
properly adjusted. In cases where good vision is present in both eyes
the Maddox rod test should be used, the rod being placed before the eye
not being operated on; the bar of light produced by the rod should pass
through or within a few inches of the light if the adjustment has been
performed accurately.
The tendons of the recti muscles are inserted into the globe at the
following distances from the corneo-sclerotic junction: internal, 5 mm.;
inferior, 6 mm.; external, 7 mm.; superior, 8 mm. Each muscle is held in
place by expansions on either side of the tendon as well as by the
tendinous insertions. Division of these expansions allows a greater
retraction of the muscle and is, therefore, to be undertaken when a
considerable degree of squint has to be overcome. On the other hand,
there will be a danger that the muscle may not regain a proper
attachment to the globe if division be too freely performed, and a
squint in the opposite direction may result; proptosis also may be
caused thereby. It is, therefore, better to combine tenotomy with
advancement in high degrees of squint over twenty degrees convergent and
in all cases of constant divergence. This is usually better than
performing a tenotomy in the other eye, as there still remains the
muscle of the other eye in reserve to tenotomize if necessary, if the
advancement be insufficient to correct the squint. Further, it is much
easier to rectify a muscular error by accurate tenotomy than by
advancement. Division of the tendon of the internal rectus only, without
its expansion, will usually rectify cases of latent convergent
strabismus with a deviation of about 12° prism (Maddox test). Cases of
latent divergent strabismus of about 8° prism (Maddox test) require
complete division of the tendon of the external rectus, and, in some
cases, of the expansion as well. Tenotomy of the superior rectus for
hyperphoria should only be undertaken in bad cases; that is to say, of
over 12° prism, any lateral deviation being first corrected, as
occasionally the correction of the lateral deviation, especially when
this is due to the faulty insertion of a muscle, will sometimes correct
the hyperphoria present.
Partial tenotomies are performed by some surgeons for the correction of
latent muscular errors, but the experience of most in this country is
that little benefit is gained unless the tendon be completely divided.
Tendon-lengthening by various methods has been performed, but has not
come into general use.
After all operations upon the ocular muscles both eyes should be
occluded to keep the eyes at rest whilst the muscle is gaining its fresh
attachment to the globe; this usually takes about seven days, after
which time both eyes should be uncovered, and if there is a tendency to
convergence atropine should be used. Glasses correcting any error of
refraction should be worn.
TENOTOMY
Tenotomy may be performed by (1) the open, or (2) the subconjunctival
method.
=Instruments.= Speculum, straight blunt-pointed scissors, strabismus
hook, needle and silk, needle-holder.
=Operation.= The operation is performed under adrenalin and cocaine.
1. _By the open method._ The surgeon stands on the right side facing the
patient when dividing the right external or the left internal rectus,
but at the head of the table when dividing the right internal or the
left external rectus.
_First step._ The speculum is inserted and the patient is made to look
away from the muscle to be divided. The conjunctiva is freely divided
vertically with scissors directly over the insertion of the tendon into
the globe (see Fig. 130) and dissected backwards.
[Illustration: FIG. 130. TENOTOMY. Showing the method of holding the
scissors and the position of the hands.]
_Second step._ The tendon of the muscle is then seized with fixation
forceps and button-holed about its centre as close to the globe as
possible (Fig. 131). The lower blade of the scissors is then passed
through the hole in the tendon, and the rest of the tendon and its
expansions are divided upwards and downwards to the extent required to
bring the eye straight as tested by its appearance or by the Maddox rod
test. The strabismus hook may be inserted, both upwards and downwards,
to see that the tendon is properly divided, but all pulling on the
muscle with a hook should be avoided, as it is painful and disturbs the
muscular equilibrium. The conjunctiva is then brought together with a
fine silk suture. If the squint be over-corrected by the tenotomy, a
deep hold should be taken with the stitch so as to draw the eye back
into position.
2. _By the subconjunctival method._ This is unsatisfactory in that
accurate adjustment by division of the expansion of Tenon’s capsule is
not possible. It is painful, and is sometimes followed by a troublesome
hæmorrhage into the capsule of Tenon. Occasionally it may be of use in
some cases of amblyopic eyes where a small wound is desirable. The
conjunctiva is button-holed below the tendon, and separated from the
surface of the muscle. The capsule of Tenon is then opened below the
tendon, a strabismus hook is passed through the opening with its
concavity against the globe, and is then rotated upwards beneath the
tendon, which is subsequently divided between the hook and the globe.
[Illustration: FIG. 131. TENOTOMY BY THE OPEN METHOD. The tendon is
first button-holed about its centre and the expansions are then divided
upwards and downwards to the required extent.]
=Complications.= These may be immediate or remote.
=Immediate.= 1. _Hæmorrhage into the capsule of Tenon_, leading to
intense proptosis, only occurs when the subconjunctival method is
adopted. As a rule the hæmorrhage ceases on the application of pressure,
but occasionally it may be necessary to open up the wound and turn out
the blood-clot.
2. _Perforation of the globe_ has been known to occur during the
division of a tendon in an obstreperous patient. It should be treated as
a wound of the sclerotic (see p. 235).
3. _Tenonitis_ very rarely occurs, but may lead to matting down of all
the extra-ocular muscles and defective movements of the globe.
Panophthalmitis has been known to follow this condition.
=Remote.= 1. _Failure to correct the muscular error._ If the error be
large it must be rectified by tenotomy of the corresponding muscle of
the other eye or by the advancement of the opposing muscle of the same
eye. This should not be undertaken until five or six weeks have elapsed
since the previous operation.
2. _Over-correction of the muscular error at the time of the operation_
may be remedied by stitching the tenotomized muscle forward to the
extent required to bring the eye straight. Advancement of the
tenotomized muscle should be performed if the over-correction be only
discovered after the operation. In cases with binocular vision lesser
degrees of deviation may be corrected with prisms if they are causing
symptoms, while small errors of over-correction, of about 3° prism,
often disappear after the first few weeks.
3. _Defective movement in the tenotomized muscle_ is usually present for
the first week or two after the operation, but recovery usually takes
place after the muscle has regained its attachment to the globe; it may
persist, however, to a slight extent; this is most liable to occur after
free division of the tendon and its expansion (more especially in the
case of the external rectus), or because the tendon has not been divided
close enough to the globe. In patients with previous binocular vision
diplopia is present after the operation on turning the eyes towards the
same side as the tenotomized muscle, but this usually disappears.
4. _A granulation_ may form at the site of the tenotomy wound. It may be
due to a tag hanging from the wound or to a portion of a stitch that has
been imperfectly removed. It should be snipped off with scissors and the
conjunctiva drawn together over its base.
5. _Proptosis_ may result from too free a division of a tendon.
6. _Retraction of the caruncle_ is best avoided by closing the
conjunctival wound with a stitch, and thus pulling the caruncle forward.
ADVANCEMENT
Advancement is an operation undertaken to rectify a squint by forming a
fresh attachment for one of the ocular muscles nearer the cornea, and at
the same time shortening it. There are three main types of operation
performed:--
1. The capsulo-muscular, in which the tendon, together with the
attachment of the capsule of Tenon to it, is advanced.
2. The tendon only is isolated, shortened, and advanced.
3. The tendon is shortened by folding it upon itself.
The first operation is by far the most satisfactory of these, owing to
the fact that a broader new insertion of the muscle is obtained, which
is less likely to yield subsequently; it is the operation usually
performed in this country.
The chief cause of unsatisfactory results after advancement operations
is the cutting through of the sutures holding the tendon in position.
The various operations, which are some fourteen in number and have
mostly their respective surgeon’s name attached, differ principally in
the method of insertion of these sutures. Whichever method of inserting
sutures be used, the main factors which aim at preventing the stitches
from cutting out are (1) that the stitches should take a good hold in
the scleral and episcleral tissues on the corneal side of the wound, for
the passing of which it is most essential that the needles should be
sharp; (2) that complete rest of the muscles should be ensured by
bandaging both eyes for the first seven days after the operation; (3)
that the opposing muscle should be tenotomized so as to prevent traction
on the sutures.
[Illustration: FIG. 132. PRINCE’S FORCEPS FOR ADVANCEMENT. Care should
be taken to see that the spring catch holds satisfactorily.]
Of the many operations that have been devised the capsulo-muscular
advancement or some modification of it is most frequently used.
=Instruments.= Speculum, straight scissors, fixation forceps, Prince’s
advancement forceps (Fig. 132), four sharp needles and strong silk,
needle-holder.
=Operation.= Under adrenalin and cocaine. _First step._ The patient is
made to look away from the side on which is the muscle to be advanced,
and the conjunctiva over the muscle is freely divided with scissors, by
a curved incision with the convexity towards the cornea, and dissected
back.
_Second step._ The capsule of Tenon is button-holed by a small incision
well above or below the tendon. A tenotomy hook is passed beneath the
tendon and its expansion and brought out through a small hole in Tenon’s
capsule on the opposite side of the tendon. The smooth blade of Prince’s
forceps is then inserted in place of the hook, and the tendon with its
expansion is grasped between the blades. The forceps are given to an
assistant, who should avoid all traction on the muscle. The eye is then
rotated in the direction of the muscle to be advanced, and tenotomy of
the opposing muscle is performed by the open method.
_Third step._ The muscle to be advanced and its expansion, which are
clamped between the blades of Prince’s forceps, are separated from the
globe with the scissors and given again to the assistant to hold. Three
strong silk sutures are passed in the following order, middle, upper,
and lower, first through the conjunctival and episcleral tissue on the
corneal side of the wound and then as far back as possible through the
muscle and out through the conjunctiva near the cut margin on the other
side of the wound (Fig. 133). Care should be taken that the middle
stitch is passed through the episcleral tissue exactly opposite the
horizontal plane of the cornea and the central portion of the tendon.
The portion of the tendon and capsule within the grasp of the forceps is
then removed with scissors by cutting close to the blades of the
Prince’s forceps, taking care not to cut the sutures.
[Illustration: FIG. 133. ADVANCEMENT BY THE THREE-STITCH METHOD. Showing
the sutures in position. A firm hold on the sclerotic to the corneal
side of the wound is essential to the success of the operation.]
_Fourth step._ The middle suture should be first tightened to the extent
required to bring the eye straight. The upper and lower sutures are then
tied.
If, on testing with the Maddox rod, the error be found to be slightly
over-corrected by the advancement, the eye can be drawn back by taking a
firm hold with the conjunctival stitch over the tenotomy wound. The
conjunctival stitch may be removed on the fourth day, but the stitches
holding the advanced muscle in position should not be removed till after
the tenth day. Atropine in both eyes is desirable, especially when
there is any tendency to convergence. Glasses should be worn on
uncovering the eyes.
=Complications.= 1. _The eyes may not be straight after the operation._
No further operation for rectification should be undertaken for at least
two or three months. If there be a tendency to convergence, glasses
should be worn and atropine used. Small latent errors may be corrected
by prisms. _If the muscular error be insufficiently corrected_ tenotomy
may be performed on the other eye. _If the muscular error be
over-corrected_ it may also require tenotomy on the other eye, the
adjustment by tenotomy being more accurate than that by advancement.
2. _Thickening over the site of the advanced muscle_ usually disappears
in a few months.
Other complications as described under tenotomy may occur (see p. 250).
CHAPTER VII
ENUCLEATION OF THE GLOBE AND ALLIED OPERATIONS
The principal substitutes for simple enucleation are evisceration,
Mules’s and Frost’s operations.
ENUCLEATION
Enucleation is the removal of the globe from Tenon’s capsule.
=Indications.= Enucleation should be performed in preference to Mules’s
operation in--
(i) Malignant tumours.
(ii) Injuries followed by cyclitis.
(iii) Painful blind eyes.
In _malignant tumours_ enucleation should only be performed when there
are no signs of extra-ocular extension. If extra-ocular extension be
present, evisceration of the orbit should be performed, provided there
be no evidence of general metastasis. In cases of glioma of the retina
it is especially desirable that the optic nerve should be cut as far
back as possible and the cross-section carefully examined for gliomatous
tissue, since the disease spreads to the brain along this structure.
_In injuries followed by non-suppurative cyclitis_ enucleation or
Frost’s operation is preferable to Mules’s operation, since cases have
been recorded of sympathetic ophthalmia following the latter operation,
and it is these cases of non-suppurative cyclitis which are especially
prone to give rise to that disease.
_Blind painful eyes_, especially when affected with glaucoma, are best
removed, as occasionally the underlying cause, when not known, may prove
to be an intra-ocular growth.
=Instruments.= Speculum, fixation forceps (two pairs), straight
scissors, strabismus hook, strong curved scissors.
=Operation.= Before the anæsthetic is administered the forehead should
be marked over the eye to be enucleated, so as to guard against the
accident of removing the wrong eye. It is usual, at any rate in the case
of hospital patients, to get their written consent for the operation.
_First step._ The speculum is inserted. In the case of the right eye the
conjunctiva is seized with the fixation forceps downwards and outwards,
or in the case of the left eye, downwards and inwards. The straight
scissors being held with the right thumb and ring finger, the
conjunctiva is divided freely all the way round, as close as possible to
the cornea, and dissected back.
_Second step._ The capsule of Tenon is opened below the external rectus
by grasping it with forceps and buttonholing it with the scissors. The
strabismus hook is passed through the opening made in Tenon’s capsule
with its concavity against the globe, turned upwards beneath the tendon,
and the latter is pulled well forward and freely divided from above
downwards between the hook and the globe. The superior and inferior
recti are treated in a similar manner. In dividing the internal rectus a
small portion should be left attached to the globe, so that subsequently
it can be grasped with forceps to rotate the globe outwards when
dividing the optic nerve.
_Third step._ The globe is dislocated between the lids by opening the
speculum widely and pressing it backwards. If the globe will not
dislocate, it is either because the tendons are imperfectly divided, or
the palpebral aperture is too small to allow of its delivery; the latter
is liable to be the case in small children or in those with a
staphylomatous globe. In such cases the palpebral fissure should be
enlarged by dividing the outer canthus.
[Illustration: FIG. 134. ENUCLEATION. Method of suturing the
conjunctiva; the suture requires no knot.]
The _fourth step_ is the division of the optic nerve. The globe is
rotated strongly outwards, either by pulling on the tendon of the
internal rectus or by pulling the globe outwards with the finger; the
optic nerve is felt for by passing the strong curved scissors behind the
globe. When the nerve is defined the blades are opened widely, pressed
backwards, and the nerve divided. The globe is then pulled forward with
the finger, and the oblique muscles and remaining attachments divided.
Hæmorrhage is easily controlled by pressure and the use of adrenalin.
_Fifth step._ When the bleeding has ceased, the conjunctival wound is
united in a horizontal direction by means of a thick silk suture running
over and over; no knot is required and the ends are left long, so that
it may subsequently be removed easily (Fig. 134). The usual dressings
are applied with a firm pressure bandage for the first six hours. The
suture should be removed at the end of the seventh day. No artificial
eye should be worn for at least six weeks after the operation, and then
only for a few hours at a time until the conjunctiva becomes accustomed
to it. It should always be taken out at night.
=Complications.= These may be immediate or remote.
=Immediate.= _Cutting into the globe._ This may occur during the
division of the optic nerve, and is usually due to imperfect dislocation
of the globe. Although of little consequence as a rule, it may be
extremely serious, as for instance in the case of an intra-ocular
growth, when it is conceivable that a portion of it might be left
behind. If this accident should happen, the portion of the sclerotic and
choroid left behind should be carefully sought for and removed.
_Adhesion of Tenon’s capsule._ Eyes that have been the subject of acute
inflammation are much more difficult to enucleate, owing to adhesion of
the surfaces of Tenon’s capsule. In these cases the globe has
practically to be dissected out of that structure.