THE PATHOLOGICAL ANATOMY OF COUCHED EYES
Being the Hunterian Lectures delivered before the Royal College of
Surgeons of England on February 19 and 21, 1917
_The material at our disposal consists of 54 globes_, the great
majority of which were removed in the Madras Ophthalmic Hospital in
the period from 1911 to 1915, though some are of much older date. They
were placed in 5 per cent. formalin immediately on removal, and were
subsequently frozen and bisected. In a number of instances one half
of the eye was submitted to microscopic examination after suitable
sectioning. Each of the half-globes and a number of microscopic
specimens have been photographed for purposes of illustration. It will
be convenient to classify our observations under a number of separate
headings.
=The Various Directions in which Dislocation of the Lens is found to
have taken place.=
Before considering this subject in the light of the pathological
specimens before us, it is necessary to make certain preliminary
statements:
1. Inasmuch as all our material is derived from blinded eyes, it is
obvious that we are dealing with the coucher’s failures alone, and
are excluding his successes. In a very large percentage of the latter
the lens is seen, during life, to be floating freely in the vitreous,
apparently untrammelled by adhesions.
2. The position in which we find the lens on bisection of the eyeball
is not necessarily that into which it was thrust at the time of
operation, for the changes which occur in the eye as a result of
inflammatory action may profoundly alter the position into which the
lens was originally forced by the coucher. Nor must we forget that
in those globes, in which the cataract is not tightly tethered by
adhesions, gravity plays a part.
Having thus cleared the ground, we may start with the statement
that, though the lens may be displaced in any direction within the
sclero-corneal coat, backward dislocations are by far the most common,
whilst forward ones were only found 4 times in the whole series
of 54 globes. None the less, each of these latter cases possesses
considerable interest.
=Forward Dislocations.=--(1) In No. 8[1] the couching instrument passed
through the limbus, and the track of the wound can be plainly followed
in microscopic sections. The ciliary body was pushed bodily away from
the sclera, and the lens nucleus was forcibly thrust into the space
formed by this cyclodialysis (Pl. II., Fig. 10); it is to be
seen imbedded in a mass of inflammatory exudate, whilst its capsule,
with some of the cortex, lies in the normal situation.
[1] The whole series of specimens has been presented to the Royal
College of Surgeons of England. The present chapter forms a descriptive
catalogue of the most instructive of them. The original Madras numbers
within the bottles have been retained, and are here quoted for ready
reference.
(2) In No. 44 the capsule and the nucleus of a Morgagnian cataract
are seen floating in the vitreous chamber (Pl. II., Fig. 11). During
life the nucleus frequently passed backwards and forwards between the
aqueous and vitreous cavities. The same phenomenon, though rare, has
been observed in other couched eyes.
(3) No. 61 is probably an instance of the same kind of thing having
happened at an earlier period (Pl. II., Fig. 12). Now, however, the
small dark Morgagnian nucleus is seen fixed in the lower part of the
anterior chamber, into which it doubtless gravitated by its own weight,
and there set up inflammatory mischief, which led to its adhesion to
the surrounding parts, and to its becoming fixed _in situ_ by the
formation of organising exudate.
(4) In No. 108 the only evidence of lens material present was the
capsule of a Morgagnian cataract, which lay impacted in the lower part
of the anterior chamber (Pl. II., Fig. 13). On section, Morgagnian
fluid escaped, and no trace of a nucleus could be detected. It is of
interest to record that the writer has, on a number of occasions,
operated on Morgagnian cataracts in which the lens nucleus had been
reduced to the thickness of a lamellar disc, or in which no trace of a
nucleus could be detected. In this case no adhesions had formed, and
during the transit of the specimen to England the capsule fell from its
position to the bottom of the bottle.
PLATE II
Fig. 10: Specimen No. 8, Whole-Section.--The lens can be seen
dislocated between the ciliary body and the sclera; the pectinate
ligament had been ruptured at the operation.
Fig. 11: Specimen No. 44.--The small Morgagnian nucleus lies in the
anterior part of the vitreous chamber; it passed freely between this
and the aqueous chambers, sometimes appearing in the one, and sometimes
in the other. The scar of the operation wound can be seen in the lower
part of the illustration, close to the ciliary body. Notice the folds
into which the detached retina has been dragged by the shrinking
inflammatory exudate. A tongue, consisting of the posterior surface of
the iris, was stripped back at the time of operation, and can be seen
attached posteriorly to the front of the hyaloid body.
Fig. 12: Specimen No. 61.--A small dark Morgagnian nucleus lies
impacted in the lower angle of the anterior chamber, which is largely
filled by a flocculent coagulated exudate. Notice the coagulated
subretinal exudate, and the cyst in the outer wall of the lower part of
the retina.
Fig. 13: Specimen No. 108.--The capsule of a Morgagnian lens lies
impacted in the angle of the anterior chamber; it had contracted no
adhesions. The vitreous body is represented by a fine cone of exudate,
which stretched forward from its apex at the optic nerve to a broad
base at the ora serrata.
Fig. 14: Specimen No. 50.--A large Morgagnian cataract floated free in
the vitreous chamber. The retina is extensively detached.
Fig. 15: Specimen No. 136.--A large hard laminated lens lies lightly
imprisoned in the inflammatory exudate which formed in the vitreous
body. A long curved scar can be seen over the ora serrata at the
temporal side of the specimen.
[Illustration: PLATE II.
Fig. 10 (No. 8).--Lens dislocated between cil. body and sclera.
Fig. 11 (No. 44).--Left eye, lower half.
Fig. 12 (No. 61).--Left eye, temporal half.
Fig. 13 (No. 108).--Right eye, nasal half.
Fig. 14 (No. 50).--Right eye, lower half.
Fig. 15 (No. 136).--Left eye, upper half.]
=Backward Dislocations.=--Dislocations backward are the rule, and very
wide variations are found both in the completeness and in the direction
of the displacement.
Those in which the _lenses_, or their nuclei, have been _completely
dislocated into the vitreous, and there lie floating_ more or less
freely (Pl. II., Fig. 14), are 9 in number. In 7 of them
the cataracts were Morgagnian, and in the 2 others there was a bulky
nucleus with a thin covering of stiff cortex. In 7 the tension of the
globe was high; in 6 the retina was completely or nearly completely
detached, and in 2 of them it was so much folded as to limit the
movements of the lens.
From a consideration of the lenses found floating in the vitreous,
we turn to that of those which were _entangled in a more or less
consistent inflammatory exudate occupying the vitreous chamber_
(Pl. II., Fig. 15). During life such lenses were reported to
be fixed, or nearly so. In the specimens they are seen to be nested
in a mass of exudate, which holds them imprisoned against the ciliary
body and the back of the iris. Usually this exudate is limited in
quantity and is confined to the anterior portion of the eye, and
principally to the neighbourhood of the dislocated lens. More rarely
it is very abundant, and occupies a large part or even the whole of
the vitreous chamber (Pl. III., Fig. 16). We shall deal with
this exudate more fully at a later stage; for the present it suffices
to state that it is inflammatory in origin, and that it contains a
large number of cells. Of the 6 cases which form this group, 3 were
Morgagnian cataracts; 5 were certainly dislocated in their capsule, the
sixth is hidden in such dense exudate that it cannot be clearly seen.
It is desirable to make it clear that intermediate forms are found
between this group and the previous one. In other words, there is no
hard-and-fast line between the cases in which the lenses float freely
in the vitreous and those in which they are, to a greater or less
degree, tethered by the pathological thickening of the hyaloid body.
We have next to consider a group of 10 eyeballs, in each of which
the dislocated _cataract was firmly fixed to the ciliary body and
to the back of the iris by definitely organised fibrous tissue_
(Pl. III., Fig. 17). These globes present certain well-marked
features of some interest: (1) The percentage of Morgagnian cataract is
much lower than that in the preceding groups, and corresponds closely
with the normal frequency of this form of cataract in Indian practice.
(2) The cataract was dislocated _in its capsule_ in no less than 8
of the 10 cases. (3) The retina was totally detached in 2 and very
extensively so in one; in every one of the remaining 7 this membrane
showed the presence of white dots, apparently on its surface. (4) The
time which had elapsed since operation in the cases falling under this
group is remarkable. In one it is given as seven months; in 2 others
there is no history; in the remaining 7 the duration was from two to
twenty years, with an average of well over seven years. The association
of the presence of white dots with these long histories is remarkable,
and will be taken up in a later section.
No. 99 (Pl. III., Fig. 18) is a specimen of special interest
for two reasons--viz., (1) the cataract is fixed to the globe unusually
far back, being attached to the retina a little behind the equator of
the eye; (2) the dislocation has taken place in an upward direction,
and therefore against the action of gravity. From time to time we meet
clinically with a couched lens whose suspensory ligament, though torn
through over a wide circumference, has been spared at one part, which
acts as a hinge. The loosened lens flaps backwards and forwards with
the movements of the eye, at times obstructing the pupil, and at others
being lost to sight. If the hinge is above, the cataract usually blocks
the pupil when the head is erect; but one meets with cases in which the
lens floats up out of the way unless the face is thrown forward into
the horizontal plane; this is apparently due to a check-ligament action
of the remaining suspensory fibres of the lens, acting on a lens which
is very nearly of the same specific gravity as the vitreous in which it
lies. Should inflammation be set up in such an eye and the lens become
involved in the exudate, it may become fixed, as in this case, in the
upper segment of the globe.
PLATE III
Fig. 16: Specimen No. 197.--The exudate into the vitreous cavity is
abundant and opaque, concealing the dislocated cataract. (Time since
operation, one month.)
Fig. 17: Specimen No. 37.--The lens is tied to the back of the iris and
ciliary body by firm organised exudate, which is continuous with and
part of the cone of inflammatory material representing the shrunken
vitreous. Notice the advanced organisation evident in the apex of the
cone near the optic nerve, also the white line apparently representing
the hyaloid canal. Some large dots and many small ones are to be seen
on the retina.
Fig. 18: Specimen No. 99.--A large lens in its capsule is dislocated
upward and inward, and is adherent to the retina by inflammatory bands.
The retina shows very numerous white dots. There is a tendency to
equatorial scleral staphyloma.
Fig. 19: Specimen No. 171.--The retina is totally detached and rolled
up tight; cysts both false and true are to be seen in it. The lens is
imbedded in a mass of inflammatory exudate, matted to the iris and
ciliary body in front, and to the retina behind; the ciliary body
is detached. The coagulated subretinal exudate gives the specimen
the appearance of a half-marble. The sclera is folded owing to the
shrinking of the eyeball.
Fig. 20: Specimen No. 119.--From before backwards can be seen the iris,
the remains of the lens capsule, and the thickened anterior layer of
the hyaloid. The lens is dislocated backward between the second and
third of these, and is wedging them apart. The retina is detached over
nearly half the globe; this is in large part determined by the pull of
the shrinking thickened anterior hyaloid layer.
Fig. 21: Specimen No. 46.--The hard dark nuclear cataract had been
depressed; it lies in front of the unruptured anterior hyaloid
membrane, and therefore outside the vitreous cavity.
[Illustration: PLATE III.
Fig. 16 (No. 197).--Left eye, lower half.
Fig. 17 (No. 37).--Left eye, lower half.
Fig. 18 (No. 99).--Left eye, upper half.
Fig. 19 (No. 171).--Left eye, upper half.
Fig. 20 (No. 119).--Right eye, upper half.
Fig. 21 (No. 46).--Left eye, lower half.]
When we come to speak of the changes found in the vitreous, we shall
have occasion to refer to the frequency with which the hyaloid body is
represented by a shrunken cone with its apex at the optic nerve and
its base in the neighbourhood of the ora serrata. This form, which is
well known to pathologists, is due to the anatomical attachments of
the vitreous body, and to the fact that the latter undergoes shrinkage
after being thickened and opacified by the presence of inflammatory
exudate. In studying the present collection, one cannot fail to be
struck with the fact that the exudate, which fixes, or helps to
fix, the lens in its pathologic position, is one with, and part of,
this cone-shaped new formation. Before leaving the consideration of
this group, we must once again point out that no hard-and-fast line
separates it from the preceding one, and that intermediate links
between the two can easily be pointed to.
In 11 globes, _dislocated cataracts were found matted between the
iris and ciliary body in front and the completely detached retina
behind_. It is very difficult to say what the nature of the original
cataracts was, since all that one can now find is a nucleus, usually
rather dark-coloured, imbedded in a mass of inflammatory tissue
(Pl. III., Fig. 19). These nuclei are undergoing steady
reduction in bulk as the result of phagocytic action. In 7 of the 11,
the lens remnants lie either within the complete capsule or in its near
neighbourhood. The interior of the capsule is usually found to have
been invaded by the mass of inflammatory and organising tissue which
mats together all the structures (_i.e._, the iris, the ciliary body,
the remains of the lens, and the detached retina), and which occludes
the angle of the anterior chamber. The completeness of the dislocation
varies greatly. In some cases the lens is hardly moved from its usual
position, and lies in front of the anterior hyaloid membrane, whilst
in others it is displaced into the vitreous cavity. In one instance
the detachment of the retina and the inflammatory changes are sharply
limited to the lateral half of the eye towards which the cataract was
dislocated, but this case belongs more to the next group than to the
one we are now discussing.
There are three outstanding and very important features common to these
cases: (1) In the great majority of them there is evidence that the
operation was followed by severe iridocyclitis; (2) 9 of the 11 were
shrinking eyes with low tension; and (3) the time which had intervened
between the couching and the enucleation was between one and two years
in every case save one, in which it is probable that the furnished
statement of three months was inaccurate. It will be noticed that the
histories are much shorter than those in the previous group. This,
together with the other two points mentioned, indicates that we have to
deal with a condition widely different from that in any of the previous
groups. Here the inflammatory process had been induced by a septic
infection of the eyes of a decidedly more virulent character, though it
fell short of that acme of infectivity, which leads in so many cases of
the Indian operation to panophthalmitis and destruction of the globe
within a few weeks.
We come next to a group of 5 cases, which have one feature in
common--viz., that the cataract, though _dislocated backwards, lies
distinctly in front of the anterior hyaloid membrane_, and therefore
outside the vitreous cavity (Pl. III., Figs. 20 and 21). In
3 of them the solid parts of the lenses have been pushed back from
their original position in such a way that they act like wedges,
forcibly keeping the anterior hyaloid membrane in a plane posterior to
that which it would normally occupy. Out of these 5 cataracts 4 were
cortico-nuclear; the fifth was too much altered for it to be possible
to state what its nature was. In certainly 4 out of the 5 moderately
severe iridocyclitis had followed the couching, but the exudative
process was a much less severe one than that which characterised the
specimens of the previous group. The consequence was that there was
no such matting of all the parts concerned as is there seen. In every
case the detachment of the retina was complete or nearly so, but in
not one was the lens enwrapped in its folds. This we may attribute to
two causes: (1) a merely contributory one, that the vitreous cavity
was not invaded; and (2) that the infection was less virulent, and
the inflammation consequently less severe, than in the members of the
previous group.
There is a small group of 3 cases in which the remains of the lens lie
_in situ_ in the periphery of the capsule, whilst the central portion
has disappeared. These resemble the peripheral after-cataracts not
infrequently seen following the extraction of a not fully mature lens.
In conclusion we have to mention 2 specimens in which the condition
found was so unusual that it would scarcely have been possible to have
anticipated its occurrence.
The first of these was one of the earliest globes sectioned. A
Morgagnian lens, entire in its capsule, was found _thrust behind the
retina_. It lay against the scleral coat close to the ciliary body; it
had detached the retina over a large area in the neighbourhood of the
ora serrata, and had led to a complete separation of it on that (the
nasal) half of the eye. The edge of the detached retina had contracted
adhesions to the front of the lens capsule, and was much puckered in
that neighbourhood, doubtless as the result of cicatrisation.
The second specimen (Pl. IV., Fig. 22) shows many features
in common with the last. The lens is entire in its capsule, and is
almost certainly Morgagnian; the tear in the retina through which it
was thrust has now cicatrised up, leaving a puckered scar. The retina
is totally detached, and on section the cataract lay as far forward as
the separation of that membrane would permit. The pupil was blocked
by exudate, and atrophic scars in the iris showed that there had been
extensive laceration of that membrane. The globe was removed a year
after operation.
The sequence of events in these two cases was possibly as follows:
The posterior operation may have been adopted and the incision placed
far back; a wide tear in the retina resulted; the lens, completely
separated from its attachments, was kept entire by the toughness of
the Morgagnian capsule, whilst the fluidity of its contents made its
insinuation through the retinal tear an easy matter. The fact that a
case has recently been recorded in which, in a boy of seventeen, the
lens spontaneously escaped through a 2 mm. trephine hole throws a
sidelight on such cases as these.
=Accidental Injuries to Other Structures than the Lens during Couching.=
Though the primary object of the Indian cataract coucher is to depress
the lens, he may accidentally injure any or all of the other structures
of the eye. Evidence of such damage is obtained both clinically and
pathologically.
=The Cornea.=--Opaque scars on the cornea are quite frequently seen in
the out-patient room in eyes which have been subjected to the anterior
operation, but are rendered invisible in formalin-mounted specimens
owing to the opacification of the membrane. Other evidence of corneal
injury is, however, available.
In No. 9 a corneal fistula is present, lying to the inner side of
the centre of the eye (Pl. IV., Fig. 23). The lamellæ immediately
surrounding it are largely replaced by connective tissue; the whole
thickness of the membrane is markedly reduced, and the lining
epithelium is irregular and vacuolated. The iris is very closely
adherent to the back of the cornea near the fistula, but more loosely
attached farther out. There has evidently been some ulceration of the
cornea and the formation of a limited staphyloma, which burst at a
later date, leaving the fistula now seen. It is probable that the point
of fistulisation was determined by the use of a septic instrument at
the time of operation, and that septic keratitis followed, leading to
early perforation with entanglement of the iris. On the other hand,
it is possible that the _enclavement_ of the iris occurred as the
instrument was withdrawn. In either case, the later sequence of events
included a dsecondary rise in tension, the formation of a staphyloma,
and a fresh perforation at the weakest point, resulting in the
production of a permanent fistula.
In No. 45 the lens capsule is adherent to the back of the cornea,
the iris being widely torn, and being probably also involved in the
synechia (Pl. IV., Fig. 24). All that remains of the lens is a brown
nucleus; the cataract was evidently Morgagnian. It is probable that,
after the escape of the fluid it contained, the lax capsule prolapsed
into the wound, either with the gush of fluid which accompanied the
withdrawal of the instrument or at a later date.
PLATE IV
Fig. 22: Specimen No. 138.--A large Morgagnian cataract in its capsule
lies dislocated behind the totally detached retina; the tear in the
front part of the lower half of the retina, through which the lens was
thrust, is now represented by a wide puckered scar.
Fig. 23: Specimen No. 9.--A whole-section showing a persistent fistula
of the cornea.
Fig. 24: Specimen No. 45.--A brown nucleus dislocated downward in its
capsule lies tightly adherent to the back of the iris and ciliary
body; it is fixed there by organised exudate, the bands from which
radiate out into the retina and are determining the detachment of that
membrane. The iris is torn on the nasal side, and through the tear
there passes a capsulo-corneal synechia.
Fig. 25: Specimen No. 116.--The retina is totally detached, and rolled
up like a closed umbrella. There is a retino-corneal synechia. The lens
has been reclined; it probably lay outside the vitreous cavity. The
subretinal exudate, coagulated by preparation, gives the eyeball the
appearance of a cut marble. During life the pressure of the lens, which
had been wedged backward, thrust the retina and the parts adherent
to it backward below, thus displacing the subretinal exudate there,
and causing it to bulge in the upper half of the eyeball; this bulge
effectually obliterated the upper part of the anterior chamber, whilst
the direct pressure of the lens obliterated the chamber below.
Fig. 26: Specimen No. 306.--There is a pigmented scar running through
the thickness of the sclera, just behind the level of the ciliary
processes. The optic disc is deeply cupped, and the anterior chamber is
very shallow.
Fig. 27: Specimen No. 306.--Low-power magnification of the previous
specimen shows a persistent fistula running through the substance of
the sclera; the ciliary body is impacted in its deeper part, and there
is a filtering scar on its surface.
[Illustration: PLATE IV.
Fig. 22 (No. 138).--Right eye, lower half.
Fig. 23 (No. 9).--Left eye, whole section.
Fig. 24 (No. 45).--Right eye, lower half.
Fig. 25 (No. 116).--Right eye, nasal half.
Fig. 26 (No. 306).--Left eye, upper half.
Fig. 27 (No. 306).--Microscopic section, low power.]
In No. 116 it is the retina which is impacted in the corneal wound
(Pl. IV., Fig. 25). It seems likely that in this instance
the sequence of events was as follows: A severe plastic inflammation
resulted from the couching, and involved among other structures a
capsular synechia, which had formed at the time of operation or soon
after. The vitreous became heavily infected, and the consequent exudate
became adherent on the one hand to the retina, which thereby underwent
total detachment, and on the other to the capsule and its synechia. The
progressive contraction of the scar-tissue then drew the retina into
the wound. This would appear to be the most likely explanation, but
it is not impossible, in dealing with such an operation as couching,
that the retinal detachment was very extensive, and that the injury
inflicted provided a path along which a direct prolapse of the retina
may have occurred.
=The Sclera.=--A very large number of Indian cataract couchers perform
the posterior operation, and therefore make their preliminary incision
in the sclera outside the limbus. Dr. Ekambaram, who has watched these
men at work, believes that they deliberately endeavour to avoid the
ciliary body, and it also looks as if some of them purposely place
their incision below the external rectus muscle. Like his Western
confrère, the Indian surgeon does not always succeed in placing his
incision just where he wishes to; this is not surprising, as many of
these men work without any local anæsthetic, and not a few of their
patients are nervous and unruly to the last degree. Moreover, it is
more than probable that there are different opinions amongst couchers
as to the best site for the preliminary cut. These considerations will
serve to explain the variety of location of the scars, as found in the
specimens before us; indeed, some such explanation is called for, since
the cicatrices may be found as far forward as the limbus, and as far
back as the equator of the globe; what is more, they may be seen in the
present collection, not only in their common situation, on or near the
horizontal meridian, but in any of the quadrants of the eye.
As a rule, the evidence of injury to the sclera is to be inferred from
the interference with the parts beneath that coat, and such instances
will be taken up when we come to consider the lesions of the ciliary
body and choroid; but occasionally we have been fortunate enough to
hit off the scleral scar either in the original division of the globe
or during the course of sectioning of part of it for the purpose of
microscopic examination.
In No. 306 the track of the original wound can be seen as a pigmented
scar in the sclera immediately behind the line of the ciliary processes
(Pl. IV., Fig. 26). Microscopic sections show--(1) that the
pigmentation of the deeper part of the scar is due to the impaction
of uveal tissue in its depth; (2) that there is a fistulous scar
running right through the thickness of the sclera; and (3) that
the subconjunctival tissue in the neighbourhood of the wound is
permeated by large open spaces lined with endothelium (Pl. IV.,
Fig. 27). It is clear that a limited measure of filtration had
been established, but this apparently proved insufficient to keep the
tension of the eye from rising, as is shown by the deep glaucomatous
cupping and by the obliteration of the anterior chamber.
No. 43 shows a scar a little farther back, in the neighbourhood of the
ora serrata; but in this case the wound appears to have healed solidly.
The pigment of the underlying uveal tissue shows a marked disturbance,
whilst before the specimen was cut it was observed that the sclera was
pigmented in the neighbourhood of the cicatrix.
In No. 8 the wound lay in the limbus, and the solidifying scar can be
traced right through the thickness of the ocular tunic and down to the
mass of inflammatory exudate which surrounds the dislocated lens, and
fills the angle of the anterior chamber. Here, again, the pigment can
be traced some distance up into the scar, in which the uveal tissue is
distinctly entangled.
=The Uveal Tract.=--In quite a large number of couched eyes one can
see, during life, evidence of past injury to the iris in the form of
more or less extensive scars, many of which probably also involve the
ciliary body. Moreover, in other cases, one can infer the presence
of injury to the ciliary body and the choroid from the existence of
pigmented cicatrices in the sclera. Anatomically, the present series
of eyeballs affords additional information on this head. Iris scars
are fairly common. In one case, already referred to, the coucher had
effected a cyclodialysis; in 3 more the wounds lie across the front
parts of the ciliary processes; in 6 they involved the region of the
orbiculus ciliaris, and in one of these the scar lies as much on the
choroid as it does on the ciliary body (Pl. II., Fig. 15);
lastly, in 4 the wounds lie well behind the ciliary body, being placed
in 2 of them just in front of the equator, and in 2 more well behind
it. Taking them as a whole, the wounds tend to be grouped in the
outer quadrant of the eye, above or below the horizontal meridian.
It has already been pointed out that this is in accordance with
Ekambaram’s evidence as to the site of selection for the incision in
the posterior operation. Far the best method of examining these scars
is by transillumination with a bright light from behind. Some points of
interest remain for consideration.
In No. 44 the wound lay behind the ciliary processes (Pl. II.,
Fig. 11), the instrument, most probably at its point, tore off
a tongue-shaped process from the posterior surface of the iris, thus
thinning that membrane over this area; the torn portion contracted
an adhesion to the subjacent hyaloid membrane, which was itself
infiltrated with inflammatory exudate; the appearance presented is
curious and interesting.
In several of the globes scar-tissue radiates from the wound area into
the surrounding tissues, and is then a strong contributory factor
in the production of retinal detachment. In one globe (No. 130) two
scars are to be seen, one of which was evidently placed too far
back by mistake (Pl. V., Fig. 28); the eye also furnishes
contributory evidence that things did not go well during the operation,
for the iris is very widely lacerated. It seems probable that the
patient was refractory or the surgeon unskilful. In any case, it is
clear that the instrument was introduced a second time.
In No. 148 a caseating mass in the eyeball (Pl. V., Fig. 29),
lying behind the equator, was found to contain a fragment of metal; the
latter was most unfortunately lost at the time the section was cut, but
it was presumably the tip of the couching instrument, and its presence,
taken with the facts that the wound was placed very far back and that
dislocation of the lens was not effected by the operation, would seem
to indicate that the patient moved violently and that the operator
failed in his purpose. The strong but strictly localised inflammation
excited suggests that the metallic fragment was of copper, and this is
in accordance with the known facts of the case, since the probes used
by these men to displace the lens are made of that metal.
No. 72 is also a specimen of special interest. Here, too, the puncture
lay behind the equator, and there seems to have been some difficulty
in penetrating the choroidal and retinal coats, which were carried in
front of the instrument, the result being a wide separation of these
two tunics from their scleral bed (Pl. V., Fig. 30).
No. 297, removed six weeks after the operation, is an eyeball which had
undergone panophthalmitis, and had burst through a point in the sclera
on the horizontal meridian somewhere in front of the equator. It is
probable that a septic wound of entrance determined the site of the
bursting. The lecturer has seen suppurating globes in which the sclera
at one point had completely sloughed, the intense inflammation present
bearing witness to the violence of the infective process excited.
=Uveitis.=--The type of inflammation of the uvea found in these
specimens was plastic, and was mostly confined to the iris and ciliary
body. The intensity of the inflammation varied very greatly. In a
number of specimens the evidence of inflammatory action was either
absent or only to be detected on very careful examination. On the other
hand, a large number of cases present themselves at Indian hospitals
in which suppurative panophthalmitis has followed the operation of
couching. In Madras such globes were eviscerated, as it was considered
dangerous to enucleate them, and much interesting material has thus
been lost. All the intermediate stages between the very slight and
the very severe inflammations can be traced in the specimens before
us. This is in accordance with what we should have expected in what
was practically a series of inoculations of healthy globes with
pathological materials, which varied enormously in their nature and
in the quantity introduced. Nor must we forget the great differences
in the ages and in the conditions of health of the patients. The
plastic mass poured out from the ciliary body and iris had in many
cases enveloped the remains of the lenses (Pl. V., Fig. 31; also Pl.
III., Fig. 19), which can be seen in process of disintegration under
the action of phagocytosis (Pl. V., Figs. 32 and 33) or of fluid
absorption. Evidence of calcification of the lens was obtained in
at least one specimen (Pl. VI., Fig. 35), and the same process was
also found at work in the uveal coat of several others. The rupture
of the lens capsule often provides a ready path of ingress for the
inflammatory exudate, which can then be seen filling the cavity of
the capsule as well as surrounding it. The curly remains, both of the
anterior and of the posterior portions of the capsule, can be clearly
traced in many of the specimens, imbedded in dense masses of organising
inflammatory exudate. In several such, the absence of the capsule
opposite or to one side of the pupillary area, and the curled-up ends
of the elastic membrane, mark the spot where rupture was effected at
the time of operation.
PLATE V
Fig. 28: Specimen No. 130.--The iris shows a deep jagged tear. There
are two scars made at the operation, one over the posterior part of the
ciliary body, the other near the equator of the eye. Numerous white
dots are seen on the choroid and iris.
Fig. 29: Specimen No. 148.--There is a localised patch of inflammation
within the globe behind the equator; in this was found a foreign body,
probably the tip of the copper probe used in the operation. It lay in
the vitreous cavity within the retina, which is totally detached.
Fig. 30: Specimen No. 72.--The operation scar can be seen on the
temporal side of the sclera behind the equator. The choroid and retina
are extensively detached on this side, having evidently been pushed
before the instrument before it succeeded in penetrating them. To the
nasal side in the anterior part of the vitreous chamber lies a cone of
exudate, the apex of which (posteriorly) is adherent to the retina, and
has raised it from its bed in the form of a shallow bleb. The cornea
fell in during preparation; it was ulcerated. The anterior chamber was
full of pus and blood. What is left of the lens lies buried at the base
of the cone of exudate already referred to, being bound thereby to the
ciliary body and to the back of the iris.
Fig. 31: Specimen No. 171.--A whole-section of the eye shown in
Fig. 19. For details of description refer to that figure.
Fig. 32: Specimen No. 171.--Low-power magnification of a portion of
the specimen shown in the previous figure. To the right is seen the
inflamed and matted iris; beneath this lies a mass of inflammatory
exudate in which the curled remains of the lens capsule can be traced.
In this mass of exudate the lens nucleus lies imbedded, its margins
being surrounded by large phagocytes.
Fig. 33: Specimen No. 171.--High-power magnification of portion of the
previous specimen, showing some of the phagocytes much enlarged. Notice
their processes invading the lens substance.
[Illustration: PLATE V.
Fig. 28 (No. 130).--Left eye, upper half.
Fig. 29 (No. 148).--Left eye, upper half.
Fig. 30 (No. 72).--Right eye, lower half.
Fig. 31 (No. 171).--Left eye, whole section.
Fig. 32 (No. 171).--Microscopic section, low power.
Fig. 33 (No. 171).--Microscopic section, high power.]
In only one instance has any evidence of proliferative uveitis come to
light, and in this one the nodule in the iris consists of mononuclear
lymphocytes; epithelioid and giant cells are conspicuous by their
absence. The interest of this observation centres in the fact that a
large number of these globes were removed with the object of guarding
against the occurrence of sympathetic ophthalmia, or of making safer
the performance of an extraction in the opposite eye. So far as the
first indication is concerned, it would appear that the danger of
sympathetic mischief in the second eye after couching is not great.
The deduction thus drawn from pathological data is confirmed by the
author’s clinical experience, for, as far as his observations go, it
is extremely rare to see the second eye lost by sympathetic ophthalmia
after this operation.
=The Chambers of the Eye.=
=The Anterior Chamber.=--This chamber showed departures from the normal
in different directions. These will be dealt with under separate
headings.
1. _Scantiness of Contents._--One chamber was quite empty, due to
the presence of a corneal fistula (Pl. IV., Fig. 23). In
a number of cases the chamber was greatly shallowed, owing to the
encroachment of the vitreous body upon it. In these the filtering angle
was sealed by adhesion over a wide area. In a few cases _l’iris bombé_
was responsible for the shallowing of the chamber (Pl. VI.,
Fig. 34). In yet others a severe plastic inflammation had involved
the structures, lying in and posterior to the aqueous chamber, and
had matted them to the posterior surface of the cornea, thus almost
obliterating the cavity. This union had been so strong that in the
process of hardening the membrane of Descemet remained adherent to the
organised exudate beneath it, and a spurious chamber was thus formed
lying in the substance of the cornea (Pl. VI., Figs. 35 and
36).
2. _Hypopyon_ was present in 6 specimens, and in one the pus was mixed
with blood. The length of histories in these cases varied from a matter
of months up to twenty years.
3. _Hyphæma._--Blood was present in the anterior chamber in 9
specimens. In some of them it was fresh, whilst in others it was
altered and decolorised. The long histories given by a number of
these cases suggest either that there had been some recent cause
for hæmorrhage, or else that a leakage of blood had been constantly
occurring. In 2 of the eyes the iris had been torn; in every one of the
others there was evidence that severe iritis had been present.
4. _Vitreous in the Anterior Chamber._--In 4 eyeballs the aqueous
and vitreous cavities appear to have been in free communication with
each other, and filaments of the vitreous body can be traced into the
anterior chamber. In 2 of these the angle was widely open, and in the
other 2 it was closed by irido-corneal adhesions.
5. _Lens Matter in the Chamber_ (Pl. II., _Figs. 10, 12,
and 13_).--In 4 eyes lens matter was found in the anterior chamber.
In one the history showed that a nucleus had passed freely backwards
and forwards between the two chambers (Pl. II., Fig. 11). In
another a Morgagnian cataract was wedged in the angle of the chamber,
but had contracted no adhesions; in the remaining 2 the nuclear masses
were firmly fixed in position by an abundant quantity of exudate.
6. _Albuminous Exudates in the Anterior Chamber._--These were found
in 3 cases; few or no structural elements were present. During life
the contents of the chamber were fluid, but they had coagulated under
the influence of the formalin preparation of the specimens; they were
probably derived from the iris and ciliary body.
PLATE VI
Fig. 34: Specimen No. 111.--The anterior chamber is much shallowed by
the bulging forward of the iris (l’iris bombé); the pupil is blocked,
and its edges are adherent to a layer composed of the lens capsule
and the anterior layer of the hyaloid, which are inflamed and matted
together. The retina is totally detached, and the choroid partly so. A
large cyst can be seen in what was the central region of the retina. It
is cut across in the section. (See also Fig. 44.)
Fig. 35: Specimen No. 74.--From before backward we see (1) the cornea;
(2) a space which might be mistaken for the anterior chamber, but
which is really an artificial tear in the substance of the cornea (see
Fig. 36); (3) the remains of the iris and ciliary body matted in
a mass of exudate in which is imbedded (4) what is left of the lens.
Large areas of this structure have undergone calcification; the wavy
capsule can be seen surrounding the lens remnants. Behind this and
continuous with it is a further mass of exudate, which tightly mats the
folds of the detached retina to the structures already mentioned.
Fig. 36: Specimen No. 74.--A higher magnification of a portion of the
preceding section. From above downward in the figure we see (1) the
cornea; (2) the artificial space; (3) the papillary margins of the iris
imbedded in dense exudate. Lining the lower boundary of the space is
seen the greatly convoluted membrane of Descemet, which has been torn
away from its corneal attachments, having clung more tightly to the
exudate, in which the iris is imbedded, than to its normal attachments.
Fig. 37: Specimen No. 250.--A large Morgagnian cataract lies imbedded
in a fine inflammatory exudate into the vitreous cavity; in this
exudate are many white inflammatory foci. The retina also shows many
white dots, the sclera is staphylomatous, and the anterior chamber is
extremely shallow.
Fig. 38: Specimen No. 72.--The inflamed optic nerve head shows a
mass of exudate occupying the physiological cup and bulging into the
vitreous cavity. This mass is undergoing organisation, and new-formed
vessels are to be seen in it at numerous points; it was the apical
end of a conical mass which represented the infiltrated and shrunken
vitreous body. Notice the pull of the roots of the mass on the edges of
the physiological cup.
Fig. 39: Specimen No. 199.--The conical mass occupying the vitreous
cavity has here undergone a high degree of organisation, especially
towards its apex at the optic nerve and in the neighbourhood of the
ora serrata. The canal of Stilling is probably indicated by the white
irregular lines seen in the centre of the cone. The pupil is blocked
with dense exudate which fuses with that of the cone; the contraction
of the latter has completely detached the retina from its bed.
[Illustration: PLATE VI.
Fig. 34 (No. 111).--Left eye, upper half.
Fig. 35 (No. 74).--Microscopic section, low power.
Fig. 36 (No. 74).--Microscopic section, higher power.
Fig. 37 (No. 250).--Right eye, lower half.
Fig. 38 (No. 72).--Microscopic section, low power.
Fig. 39 (No. 199).--Right eye, lower half.]
=The Vitreous Chamber.=--In the great majority of the eyeballs under
examination, it was observed that the vitreous body had become
detached and shrunken, and that its remnants showed distinct signs
of infiltration, and often of organisation. The appearances observed
in the various cases fall naturally under a number of headings: (1)
Very slight evidence of vitreous structure is discernible (Pl. II.,
Fig. 14). (2) Filmy masses are present in the chamber (Pl. II., Fig.
15). These either (_a_) are confined to the anterior portion of the
chamber, or (_b_) take the form of a cone with its apex at the nerve
head, and its base in the neighbourhood of the ora serrata and ciliary
body. (3) Masses are present which give the impression of being freely
infiltrated with inflammatory material, either throughout their
substance (Pl. III., Fig. 16) or in isolated foci (Pl. VI., Fig. 37);
these may be divided into the same subgroups, (_a_) and (_b_), as
those under the previous heading. (4) A distinct fibrous organisation
is noticeable in the conical masses, which represent the detached and
shrunken vitreous (Pl. III., Fig. 17). (5) No detail is discernible
(Pl. III., Fig. 19), owing to the fact that the retina has become
detached and inextricably matted with the one-time vitreous contents,
and with the iris and ciliary body.
There are certain preliminary points which we must first settle:
1. There is no essential difference between the cases in which there
is a definite cone of filmy or infiltrated membrane reaching from the
optic nerve head to the ciliary body, and those in which deposits of
a similar nature are found confined to the anterior portion of the
vitreous chamber. The grounds for this statement are as follows: (_a_)
An examination of the more complete specimens of conical exudate shows
that the membrane becomes very slender as the nerve head is approached,
and it is obvious that very little violence would be required to break
this delicate thread across, and so to allow the whole membrane to
be gathered up by its own elasticity towards its large and strong
anterior attachments. (_b_) There is strong evidence in a number of the
specimens of this series to show that the contraction of the shrinking
inflammatory material within the globes takes place with such force as
might easily suffice to break across the slender nerve attachment of
some of these cones. (_c_) It is obvious that in not a few cases the
tapering apex of a conical exudate is likely to be cut across during
section of the globe, or broken across during subsequent manipulations.
(_d_) Specimens in which the exudates presented a definite conical
shape, when they were first cut in India, have arrived in this country
transformed during the voyage into the similitude of those in which
the exudate is loosely gathered into the fore part of the vitreous
chamber; the apex of the cone had been broken off at the nerve head,
and the exudate had moved forward by virtue of its own elasticity
toward the anterior attachments of the mass. Taking all these
points into consideration, we may conclude that in all the eyeballs
which present the appearance of shrunken vitreous the structure was
originally conical in form, and that departures from that shape are
merely artefacts. Stress is laid on this point, because in a number of
the globes the appearances present suggest that the exudate is poured
out from the ciliary body, and is confined to the neighbourhood of that
structure. We believe such an interpretation to be quite erroneous, and
to be founded on the observation of artefacts.
2. Is this appearance of a shrunken vitreous body definitely
pathological? The answer is in the affirmative, for the following
reasons: (_a_) All these globes were treated alike, being dropped
into 5 per cent. formalin solution on removal, and kept there till
frozen and cut. (_b_) Normal eyeballs treated in this way present no
such evidence of definite vitreous structure. (_c_) Every grade can
be traced in the series before us, between the appearance of delicate
filmy membranes in the vitreous and the presence of firmly organised
structures. (_d_) Though it is very difficult to examine these exudates
satisfactorily under the microscope, there are a large number of
specimens which definitely show evidence of an inflammatory exudation,
strengthening and thickening the vitreous body. In not a few of these
the anterior hyaloid membrane (the term is used in a non-committal
sense) is definitely thickened and infiltrated with inflammatory
material (Pl. III., Fig. 20). The conclusion arrived at
is that these widely varying evidences of structural alteration in
the vitreous body are to be interpreted as due to the penetration of
the hyaloid by inflammatory material of chemotaxic origin, and to
the subsequent organisation of that infiltration. (_e_) There still
remains the clinical evidence. The author was increasingly reluctant,
as his Indian experience accumulated, to remove lenses which had been
couched. It was not that vitreous escaped, but that the results of
operation were usually poor, and that the blame of the lost sight was
then apt to be most unfairly ascribed to the extraction operation. In
view of the frequent occurrence of vitreous changes, this failure to
help the patients is easily explained. Major Kirkpatrick has taken a
different, and possibly a more generous, view of the position, and has
removed a number of these couched lenses. His evidence is of extreme
interest in the light of our recent pathological findings; he has been
“struck by the rarity of vitreous escape even after a fairly extensive
investigation with a spoon” in extracting couched lenses. He adds:
“I have noticed that the vitreous body becomes shrunken and
extraordinarily tough, so much so that when an eye is excised (either
for glaucoma or for iridocyclitis following Mahomedan operation),
the whole globe can be held up by a strabismus hook transfixing the
vitreous, though the latter appears perfectly clear. The vitreous
undoubtedly does undergo shrinkage, and leaves a large space, which is
occupied by aqueous.”
Straub[2] has described some experiments which he made on animals,
in the course of which he injected pathogenic organisms either into
the vitreous or into the ciliary body. The result varied according
to the part infected, and the poisoned area attracted leucocytes by
chemotaxis to itself. Particular interest attaches to the following
of his findings: (1) The optic nerve head was swollen and filled up
with leucocytes; (2) there was evidence “that the lymph current of the
vitreous goes by the optic nerve, and that chemotaxic substances are
brought by this current from the granuloma (the artificial infection)
to the nerve”; (3) the leucocytes found in the vitreous showed the way
from the granuloma to the cup of the optic nerve--they were seated on
thin membranes, and most of them were heaped together in small dots;
(4) aggregations were found on the walls of the cavities of the eye
(on the cornea, on the retina, on the lens capsule, etc.), attracted
there, in Straub’s opinion, by a chemotaxic action.
[2] “The Pathology of Dust-like Bodies in the Vitreous,” etc., Trans.
of the O.S. of the U.K., 1912, xxxii. 60.
In the experiments above considered, which were very limited in number,
an effort was made to localise the infection to one or other part
of the eye, and to work with a virus (tubercle bacilli) which was
comparatively constant in its toxicity.
What Straub did with a few eyes has been done in the series now
before us, by the Indian coucher, in fifty-four. The interest of the
experiments is heightened by the fact that, whereas in the Dutch
experiments the toxicity of the virus was kept as constant as possible,
in the Indian ones it varied from that of organisms which took many
years to destroy the sight to that of one which at once produced a
fulminating panophthalmitis. One point more: The Indian operator made
no effort to confine his procedure (and with that procedure went
infection) to any one structure; sometimes he attacked the lens from
in front, and in doing so he often primarily injured the iris, but may
have spared the vitreous chamber; sometimes he entered through the
ciliary body or through the choroid, opening up the hyaloid cavity
in doing so. His want of skill and the slenderness of his anatomical
knowledge made him catholic in the damage he inflicted, but running
through his work is the trail of septic infection of the eyeball by
penetrating wounds. The result is that he has provided us with a large
material of extraordinary interest in the study of the problem which
Straub started on.
_The Filmy Masses in the Vitreous Chamber._--As has already been
stated, the contents of the vitreous chamber in these specimens vary
from thin gauzy films, which can only be detected by careful search, up
to thick masses which strike the eye as soon as the specimen is looked
at.
It is not easy to obtain a view of these exudates in section, but
nevertheless they appear in a considerable number of the microscopic
specimens, and their character is always the same; they consist of
more or less structureless masses with blood-cells and leucocytes
imbedded in their substance. In fact, they would seem to be identical
with the membrane spoken of by Straub as harbouring the leucocytes
which gave rise to dust-like and other opacities of the vitreous in
his experimental cases. At a later stage, or perhaps in cases where
the inflammation has been of a more plastic character, a distinct
fibrillation of the exudate can be seen, and there may even be evidence
of a definite fibrous tissue formation. If we confine our attention
for the moment to those eyeballs in which the exuded mass is devoid of
structure in the anterior portion of the cone, we shall find that, on
tracing it back toward the apex by which it is attached to the optic
nerve, it becomes more highly organised and more richly cellular,
whilst fibrillation and fibrous tissue formation make their appearance.
The same thing, though in a lesser degree, may be observed in the
neighbourhood of the ciliary body, doubtless due to the presence of a
plastic exudate derived from that structure.
An examination (Pl. VI., Fig. 38) of the optic nerve and
of the exudate attached to it reveals the following features: (1)
The nerve head is congested, and its vessels stand out in prominent
relief. (2) There is a considerable effusion of leucocytes in the
neighbourhood of these vessels. (3) A mass of exudate fills up and
projects from the optic nerve cup, whether this latter is physiological
or glaucomatous. This mass is clearly contracting, and thereby pulling
on the tissue which lines the edges of the cup. (4) Along the centre of
the projecting exudate are to be seen (_a_) an abundance of mononuclear
cells; (_b_) the commencement of a fibrous tissue formation; and (_c_)
a new formation of bloodvessels.
The appearances above enumerated would indicate that we have to do
with an inflammation of the optic nerve, which had been induced by
chemotaxic substances brought thither along Stilling’s canal. Such
an idea is not a new one. It was suggested by Straub in order to
explain the optic neuritis he found in his two cases of experimental
inoculations of the ciliary body, and it also enjoys provisionally the
support of Fuchs’s[3] authority. The idea that part of the lymph of
the eye passes backward along a passage corresponding to the central
hyaloid canal is not generally accepted, and rests largely on inference
from the observation of pathological specimens. It would be difficult,
however, for anyone who has carefully studied this series to doubt
that such a flow exists; it is, of course, not suggested that any large
percentage of the lymph travels in this direction.
[3] Fuchs: “Textbook of Ophthalmology,” Duane, fourth edition. 1911, p.
16.
A confirmation of these views is obtained if we refer to the three
eyeballs in which the organisation of the cone of exudate into the
vitreous has attained the highest development. We notice in these how
extremely far this process of organisation has been carried in the apex
of the cone, where it is represented as a well-defined opaque cord (Pl.
VI., Fig. 39; and Pl. III., Fig. 17). In one of the three a fibrous
band, presumably the remains of the canal of Stilling, is clearly
seen, whilst in the two others the existence of this structure is at
least indicated. It is possible that in the first-named a congenital
peculiarity exaggerated the distinctness of the appearance.
=The Retina.=
Detachment of the retina occurred in 38 of the 54 globes (70·38 per
cent.), and was absent in 16 (29·62 per cent.). It was partial and
ill-marked in 5 (9·25 per cent.), extensive in 9 (16·68 per cent.), and
complete in 24 (44·44 per cent.). The ocular tension was above normal
in 11 out of the 16, which presented no detachment, but in only 6 out
of the remaining 38; it was below the normal in 13 of the 24 globes
with complete detachment, and above it in 3 of them. In the very great
majority of the eyes the detachment of the retina was undoubtedly due
to traction from within. The sequence of events is plain from a study
of the whole series.
At the operation there was an infection of the coats of the eye, and
also of the vitreous chamber from without; this led to the formation
of inflammatory material within the vitreous chamber; adhesions took
place between these new-formed membranes and the retina; finally the
shrinkage of the organising inflammatory material tore the retina
from its bed. Every step of the process can be traced either in
microscopic sections or in the naked-eye specimens. The earliest
possible stage is seen under the microscope in sections of an eyeball
(No. 37), where in the neighbourhood of the ora serrata the shrinkage
of the exudate within the vitreous chamber has just begun to lift the
retina from its bed. The individual points of attachment between the
inflammatory membrane and the retina are beautifully illustrated. The
ultimate stage of the process is to be found in those cases in which
the retina is not merely totally detached, but has shrunk posteriorly
into a stick-like form (Pl. III., Fig. 19, and Pl. IV.,
Fig. 25), whilst it opens out anteriorly into a mass in which the
iris, the ciliary body, the lens, the remains of the vitreous, and
the retina are inextricably matted and tangled. When sections of such
specimens are examined under the microscope, their leading feature is
the evidence of severe plastic iridocyclitis, with the formation of
abundant cicatricial tissue, which mats all the parts together and
severely distorts the normal anatomical arrangement. The retina is
dragged forward from the neighbourhood of the ora serrata over the
ciliary body, whilst elsewhere it is thrown into abundant folds and
completely separated from its normal attachments. A pseudo-cystic
condition is thus produced, the apparent cysts being formed by the
elaborate folding of the membrane (Pl. III., Fig. 19, and
Pl. V., Fig. 31). These may be small and slit-like, or may be
large and round, so simulating the appearance of true cysts. In front
of the retinal mass, lens fragments and capsule are seen in a number of
the specimens entangled in the scar-tissue. As has already been said,
all grades can be traced, from the slightest detachments up to those
we have just been describing. The greater or less degree of separation
of the retina met with in the different globes is doubtless in part a
question of time, but it is also, and probably to a much larger extent,
one of the character and grade of the inflammatory process excited in
the eyeball. The more plastic the type of inflammation and the more
intense the process is, the greater will be the measure of ultimate
cicatrisation, always provided that the inflammation is not intense
enough to result in suppuration.
There are several different ways in which the exudate which forms
within the vitreous chamber may be placed in a favourable position for
the production of retinal detachment.
1. The first of these is illustrated by each of those globes (Nos. 44
and 72) in which the site of a wound of the retina forms the point of
connection between that membrane and the inflammatory exudate lying
in the vitreous cavity (Pl. V., Fig. 30). The traumatic
infection of the retina served to attach the vitreous exudate to its
walls, and thus paved the way for the separation of the membrane. In
one of these cases (No. 44) a longitudinal fold was detached, whilst in
the other (No. 72) the detachment was broad and shallow.
2. In the second method also, it is necessary to postulate an infection
of the retina before that membrane could have contracted adhesions,
either localised or widespread, to the neighbouring vitreous exudate.
Once, however, the virus was planted within the hyaloid chamber, it
probably diffused itself widely, and by means of chemotaxis set up an
inflammation of the retina; evidences of such a retinitis abound in
many of the specimens. Attachments between the vitreous exudate and the
retina having been thus formed, the contraction of the former would
naturally lead to the separation of the latter from its choroidal bed.
3. In a few of the globes the contracting membrane is merely an
infiltration and thickening of the anterior layer of the hyaloid. It
is well known that the vitreous body is, under normal conditions, more
firmly attached to the retina in the neighbourhood of the ora serrata
than it is elsewhere; it is therefore obvious that an inflammatory
contracting membrane in the anterior part of the vitreous will pull
throughout its whole circumference on the retina in its neighbourhood,
effecting a detachment over a very wide area (Pl. III.,
Fig. 20). This is just what we see happening in the globes we are
now discussing.
4. In a number of the specimens it can be clearly seen that the
bands, which drag upon the retina, radiate from the remains of lens
masses, which are themselves encased in inflammatory tissue, and are
bound thereby to the iris and ciliary body in their neighbourhood.
Such bands appear in some cases to lie in the substance of the retina
itself (Pl. IV., Fig. 24); in others they are situate in the
vitreous and present the form of membranous sheets, separated from the
subjacent retina only by narrow spaces, and finding attachment to it in
the neighbourhood of the equator (Nos. 117 and 170). The characteristic
of these cases would appear to be that the dislocated lens is in
them the principal focus of sepsis within the eye. The point is of
interest, since some of them, at least, represent ruptured Morgagnian
cataracts; for there is reason to believe, on clinical grounds, that
the liberation of Morgagnian fluid within the eye is, sometimes at
least, productive of considerable irritation to the surrounding parts.
There are two globes in the collection in which the exudate within the
hyaloid cavity, converted into organised fibrous tissue, is obviously
tearing the retina from its bed in the course of its contraction. A
very interesting feature of these eyeballs is that in each of them an
opaque band which strongly suggests Stilling’s canal can be traced
forward from the optic nerve head (Pl. VI., Fig. 39).
In many of the specimens an abundant subretinal exudate is present. In
the long-standing ones, with complete detachment of the retina, this
effusion fills up the whole of the space between the retina and the
choroid. When the latter membrane is also detached, a further exudate
of similar appearance is seen between it and the sclera. Owing to the
action of the formalin, the very firm coagulation of the long-standing
effusions gives the eyes a solid and very characteristic appearance
(Pl. III., Fig. 19); the half-globes look like sections
of marbles made of fissured and clouded glass. In earlier cases the
effused mass is much less firm, but is whiter and more opaque, with
a tendency to present a flocculent appearance. The question that
naturally presents itself is, whether these effusions were the cause or
the result of the retinal detachment. The presence of the inflammatory
exudate within the vitreous, with which we have already dealt, provides
such a satisfactory explanation of the detachments of the retina
throughout this series, that it seems unlikely that the effusions in
question, whether subretinal or subchoroidal, play any causative part
whatever.
We must place in quite a different category the cases, four in number,
in which the effused fluid consisted of blood. The source of the
hæmorrhage in these cases is different from that which is met with when
the pressure within an eye is suddenly reduced by the operative opening
of the globe. In the latter case it is the large choroidal vessels
which give way, and the hæmorrhage is subchoroidal, whereas in the four
cases under review the bleeding was subretinal in one (No. 157), into
the vitreous chamber alone in one (Pl. VII., Fig. 40), and
into both the vitreous chamber and the subretinal space in two. The
hæmorrhage into the vitreous chamber was probably due to injury to the
retinal vessels by the coucher’s instrument, though it is possible that
blood may have found its way through the retinal cut from choroidal
vessels divided at the time. The subretinal probably escaped from the
severed branches of the smaller choroidal vessels. The fact that in
no case was a large subchoroidal hæmorrhage present would indicate
that the large choroidal vessels were tough enough to escape injury,
being probably pushed aside by the comparatively blunt instrument the
coucher used. In one eyeball (No. 157) large cholesterine crystals were
seen shining on the cut surface of the sanguineous mass. A similar
phenomenon was observed in the case of one of the albuminous effusions
above spoken of.
It remains to deal with a rare cause of detachment of the retina or of
the retina and choroid--viz., the application of direct violence at the
time of operation. This is best exemplified in the two globes in which
the cataract was thrust through and behind the retina, by the coucher’s
instrument, at the time of operation (Pl. IV., Fig. 22). It
is also beautifully illustrated by specimen No. 72, in which the retina
and choroid were carried in front of the coucher’s instrument before
the latter succeeded in perforating them (Pl. V., Fig. 30).
The dislocation thus produced proved permanent.
=Dots on the Retina.=--A striking feature of the series of specimens
before us is the presence of numerous dots on the retina. These are to
be seen in 16 cases, and doubtfully in a seventeenth. In at least one
other, similar dots are present on the choroid and on the posterior
surface of the iris (Pl. V., Fig. 28). We therefore find this
peculiar appearance in one case in every three; but this is far from
representing what is probably its real relative frequency, for in 24
of the globes the retina was totally detached, and it was therefore
impossible to say whether there were dots present on it or not. If we
put these 24 to one side, we find that the dots were certainly present
in 16 out of 30--that is, in well over 50 per cent. If we include the
other 2 cases above alluded to, the figure rises to 60 per cent.
In some of the specimens the dots are so large that they could scarcely
be missed under a careful naked-eye examination (Pl. III.,
Fig. 18), whilst in others they were only discovered when
highly magnified photographs of the eyeballs were thrown on a screen
(Pl. III., Fig. 17). They could, however, be found easily
with a loupe once their presence was known. The variation in different
specimens was not confined to size; some of the dots were white, others
were a pale grey, and a few were bright and shiny. Again, some of them
appeared much more sharply defined than others.
It was at first thought that manifestations so distinct under slight
magnification would yield very definite appearances under the
microscope; but, on the contrary, much difficulty has been experienced
in deciding the nature of the changes which have given rise to this
phenomenon.
One of the first points noticed was that the dots were found almost
exclusively in long-standing cases. This of itself would appear to
indicate that their cause was to be sought in some degenerative
process; but a closer analysis of the histories revealed a probable
fallacy in such an argument, since a number of the eyes had had good
vision for a long period after operation, and had eventually succumbed
to a fresh inflammatory invasion, or possibly to a more severe
recrudescence of a septic condition implanted at the time of operation.
On examination of a number of specimens, three distinct appearances
have been found, any one of which might presumably account for the dots
seen with the naked eye.
1. In some of the globes a proliferative retinitis can be found along
certain of the vessels (Pl. VII., Fig. 41). These consist
in section of masses of mononuclear leucocytes surrounding the vessel
wall, and tending to make their way to the inner surface of the retina.
It might be thought that such a change would produce lines rather
than dots, and that those lines would run along the course of the
vessels; but there are two features which make this doubtful: (_a_)
Even under the same field some of the vessels appear quite healthy
on section, whilst others show distinct masses of proliferation; and
(_b_) along the course of a vessel cut obliquely one may find the
proliferative exudate confined to one part of its course, the rest
being comparatively free.
2. In the neighbourhood of some of the inflamed retinal vessels above
spoken of, one finds on the surface of the retina what appear to be
free collections of mononuclear cells (Pl. VII., Fig. 42).
These are apparently of the same nature as the dots described by Straub
on the posterior surface of the cornea and in the vitreous body. It
will be remembered that he attributed them to chemotaxic action. It
would appear not improbable that the same explanation holds for these
retinal dots. It is of interest that, though they occur in cases of
long standing, the history of a subsequent inflammation, destructive to
vision is of a much later, and indeed, of a comparatively recent date.
The presence of such exudative masses would then be easily explained.
3. The grouping of these dots varies considerably in different
specimens, but does not lend much colour to the idea that they are
vascular in origin, for in some at least of the eyes they certainly
do not follow the course of the vessels. On the other hand, in a few
of the eyeballs there is a massing of these dots in the neighbourhood
of the ora serrata, which is in itself suggestive of a degenerative
process, since this is the area of lowest circulatory activity,
inasmuch as this region is supplied by the ultimate twigs of the
retinal vessels. This observation gathers interest from the fact that
in quite a number of these specimens it is possible to demonstrate the
presence of small cysts in the walls of the retina (Pl. VII.,
Fig. 43). These cysts are produced by the coalescence of œdematous
spaces in degenerative areas. All stages of the process can be traced
in different specimens of the series before us. Such cysts are only
likely to be met with in long-standing cases in which the degenerative
processes have had time for full play.
Inasmuch as these retinal dots are found in the cases in which the
retina is still in its normal position, it would seem probable that a
careful clinical search should reveal their presence in living eyes now
that their existence is established pathologically. It is a point which
should repay the study of surgeons who are practising where couching is
commonly resorted to, and especially in India.
PLATE VII
Fig. 40: Specimen No. 240.--The original cavity of the vitreous
is represented by a mass of blood-clot, surrounded by the walls of the
totally detached retina. The subretinal exudate is firm and abundant.
The iris and ciliary body, the lens remnants, and the anterior part of
the retina are matted together in a dense mass of cicatricial tissue.
Fig. 41: Specimen No. 175.--This shows a proliferative dot in the
retina. R, retina; SCL, sclera; CH, choroid; D, mass of leucocytes
surrounding vessel wall.
Fig. 42: Specimen No. 37.--A collection of leucocytes lying on the
inner surface of the retina, superficial to its limiting membrane, and
projecting freely into the vitreous. In the substance of the retina can
be seen the section of a vessel surrounded by a mass of leucocytes.
Fig. 43: Specimen No. 111.--Small cysts in the retina, which would
probably have coalesced before long to form a larger one.
Fig. 44: Specimen No. 111.--A whole-section of the eye already shown
in Fig. 34. The condition of l’iris bombé is well marked, the
pupillary edges being adherent to an inflammatory mass formed of the
capsule and the anterior layers of the hyaloid matted together. Notice
the large cysts occupying the central area of the detached retina, with
the macula lutea showing in its inner wall.
Fig. 45: Specimen No. 131.--A large Morgagnian lens in its capsule
was adherent to the iris base, the ciliary body, and the neighbouring
retina over a wide area. The capsule ruptured during the transit of
the specimen from India. Note the thickened white dots upon it; they
are characteristic of Morgagnian cataract. The large brown nucleus,
which escaped when the capsule burst, now lies free in the cavity of
the eye; notice the “bite” out of its edge. The optic disc was deeply
cupped, and the angle of the anterior chamber was widely obliterated,
the chamber itself being very shallow.
[Illustration: PLATE VII.
Fig. 40 (No. 240).--Left eye, lower half.
Fig. 41 (No. 175).--Microscopic section, low power.
Fig. 42 (No. 37).--Microscopic section, high power.
Fig. 43 (No. 111).--Cysts in retina. Microscopic section, high power.
Fig. 44 (No. 111).--Left eye, whole section.
Fig. 45 (No. 131).--Left eye, lower half.]
=Macroscopic Cysts of the Retina.=--It remains to speak of larger cysts
of the retina which can be recognised by the naked eye. It has already
been mentioned that, in those cases in which this membrane has been
found to be tightly folded on itself, a pseudo-cystic condition is
thereby produced; the cavities of these false cysts are merely shut-off
portions of the original vitreous chamber. Of a quite different nature
are the true cysts of the retina, three examples of which are to be
found in this collection. In one (Pl. II., Fig. 12) a narrow
slit-like cyst is seen in the outer layers of the detached retina at
its lower part. In the second, a whole-section of the globe shows a
large cyst occupying the central region, the macular area forming a
portion of its wall (Pl. VII., Fig. 44). Lastly, in the
third a large round cyst can be seen to the temporal side. A point of
interest in connection with this specimen is that it shows both true
and false retinal cysts (Pl. III., Fig. 19, and Pl. V.,
Fig. 31).
=The Choroid.=
It remains to add a few words to what has already been said about
this membrane. The great majority of the changes we have found in it
are, clearly, to be attributed to the effects either of hypertony or
of hypotony of the eye; they do not, therefore, differ from similar
appearances found under the same conditions generally.
Compared with detachments of the retina, those of the choroid are rare
in this series. In one instance, already mentioned, the two membranes
had been displaced together by the instrument used in couching
(Pl. V., Fig. 30). In another, in which severe inflammation
had occurred, the retina and choroid had adhered to each other, and
had been detached as one sheet by the contraction of an exudate, which
lay in the neighbourhood of the iris and ciliary body and in the front
part of the vitreous cavity. In a number of other globes, in which
the tension was low, the ciliary body and the anterior portion of
the choroid were found separated from the sclera as far back as the
line where the anterior segment of the latter coat was drawn over the
posterior in the manner pointed out by Treacher Collins in his work on
Hypotony (Trans. of the O.S. of the U.K., 1917).
In the previous chapter we have spoken of an appearance commonly
seen in successfully couched eyes--viz., an unusual distinctness of
the large vessels of the choroid in the ophthalmoscopic picture.
It is necessary to insist that in such cases the vessels are not
sclerosed; they are seen with unusual distinctness simply because
the pigment which usually hides them from view has disappeared. What
is more, a careful study of a number of these cases has created a
strong impression that the deficiency in pigmentation affects both the
pigmentary layer of the retina and also the pigment of the choroid. The
absence of the former lays bare what lies behind it; the absence of
the latter is inferred from the general appearance of pseudo-albinism.
These findings are the more noteworthy by reason of their contrast to
the usual deep pigmentation of the Indian eye. Some of our specimens
throw light on this phenomenon, for we observe in them two changes:
(1) The pigmentary layer of the retina is irregularly thinned and
altered, and at some points its pigment can be seen migrating into
the choroid; (2) the choroidal pigment itself is extensively altered
in an irregular manner, being heaped up in some areas and thinned in
others. It is necessary to remember that, inasmuch as our specimens are
wholly obtained from the coucher’s failures, whilst the interesting
appearance we are discussing is best seen in his successes, we cannot
expect very definite results from our pathological material, since the
changes we desire to study are there overlaid and obscured by those of
pathological processes, such as hypertony, hypotony, and inflammation.
=Glaucoma.=
It has long been known that couching is frequently followed by
secondary glaucoma. In the present series of 54 globes, 19 of them
showed evidence of high intra-ocular pressure. This figure must not,
however, be taken as a reliable index of the numerical frequency of
glaucoma as a complication of the operation. On the one hand, we
must remember that the present series deals with the failures only,
and that a large number of eyes are met with clinically in which the
lens is floating free in the vitreous chamber without any sign that
the intra-ocular tension is raised. Again, the cases which go on to
suppuration, and which are very numerous, are excluded from the present
series owing to the fact that all such were eviscerated in order to
avoid the risk of intracranial sepsis. This obviously diminishes the
total number of globes under consideration, and thereby raises the
apparent percentage of other conditions, such as glaucoma. On the other
hand, it would be a mistake to suppose that out of these 54 globes only
19 had suffered from secondary glaucoma, for in 24 of them a complete
detachment of the retina had covered up any evidence which may at some
time have existed of the presence of increased intra-ocular pressure,
though the conditions still found in some of them make it more than
probable that the globes were formerly glaucomatous. In any case, it
leaves us with the fact that, out of 30 eyeballs which were available
for accurate examination, no less than 19 were glaucomatous. In 17 of
the 19 the angle of the anterior chamber was extensively closed, and
in 3 of these the chamber was so shallow as almost to be reduced to
a potential slit. The remaining 2 are thus accounted for: In one the
angle was open save for a small marginal adhesion, and there was free
communication between the aqueous and vitreous chambers; unfortunately,
the specimen was almost spoilt in sectioning it for the microscope; in
the second, a Morgagnian lens was impacted in and had blocked the angle
of the anterior chamber.
Returning to the 17 cases in which the angle of the chamber was closed,
and to certain other eyeballs in which it seemed probable that glaucoma
had at some time been present, we found that in every one of them one
or other of the accepted causes of secondary glaucoma was revealed when
looked for; in some, more than one such cause was discoverable. We
shall content ourselves with enumerating these factors.
A corneal fistula, with evidence of past anterior staphyloma, was
present in one; here the cause of the glaucoma was evidently the
closure of the filtering angle, which resulted from the anterior
synechia; in one there was a capsulo-corneal synechia (Pl. IV.,
Fig. 24), and in another a retino-corneal synechia (Pl. IV.,
Fig. 25); in 5 the ciliary body was involved in the scar; in 6 the
dislocated lens pressed extensively on the iris base (Pl. VII.,
Fig. 45); in 3 the lenses, tilted at right angles to their normal
position, pressed the anterior hyaloid membrane severely back on the
side of the dislocation, whilst causing the vitreous to bulge the
iris forward into the anterior chamber on the opposite side; in 5 the
pupil was blocked, and in 3 of these l’iris bombé was present; in 2
the anterior layers of the hyaloid were so thickened by inflammatory
exudate as to suggest that there was an abnormal obstruction to the
passage of fluid across the membrane; in one a marked thickening of
the lens capsule in the form of an after-cataract may possibly have
provided an obstruction to the forward passage of fluid from the
vitreous; lastly, there is one globe in which glaucoma had probably
been present before the operation, if one may judge from the history of
the case and from the violent hæmorrhage which followed the couching.
It has been suggested that one of the causes of glaucoma after this
operation is an advance of the front part of the vitreous body owing to
a rupture of the anterior layers of the hyaloid during the operation.
Without in any way denying that the suggestion may be a valid one
in certain cases, the impression gained from a study of this series
is that we need look no farther than the well-recognised causes of
secondary glaucoma. We have only to remember that the trauma inflicted
is extensive and various, and that a greater or less degree of sepsis
accompanies every couching in the hands of its Indian exponents.