disease is termed _Iritis_; but in most cases all the other internal
parts suffer more or less. The iris changes its appearance, becomes
of a dusky hue, either in part or throughout, and red vessels are
sometimes distinctly seen in it; from grey or blue it changes to
a greenish colour, and when formerly black or brown it becomes
reddish. The size of the pupil diminishes, and the contraction is
often irregular, when the inflammatory action is intense. The iris
swells perceptibly, and the pupil loses its dark colour, or is almost
entirely closed, either from effusion of lymph, or from inflammation
and consequent opacity of the crystalline lens and its capsule. The
iris projects forwards, and diminishes the capacity of the anterior
chamber; the pupil is irregular, and often assumes an angular
appearance; and the irregularity becomes permanent from adhesion of
the pupillary margin of the iris to the capsule of the lens, lymph
being effused and organised, and forming a firm uniting medium between
the parts. Occasionally adhesions form at the middle of the iris, and
cause so great contraction as to give the pupil an appearance of being
double. Of course irregularities of the pupil are most distinct when
the part is dilated, either spontaneously or by the application of
belladonna. Tubercles sometimes form on the iris, and not unfrequently
it presents a granulated appearance. From the commencement of the
inflammatory attack the patient feels great pain in the organ and in
the forehead, and there is great intolerance of light. There is a
feeling of tension of the eyeball, followed by deep throbbing pain
increasing every instant. As the disease advances, the cornea is
rendered opaque by the fulness of the chambers, and the aqueous humour
becomes turbid and of a milky appearance; or lymph is effused into the
anterior chamber, and floats about in flaky portions. Occasionally the
vessels of the iris are so distended as to give way, causing effusion
of blood into the chamber, often in considerable quantity.
More frequently, however, puriform fluid is deposited, occasioning the
appearance termed _Hypopium_. The pus is either fluid or of a thick
curdy consistence: when fluid and thin, it mixes with the aqueous
humour, rendering it white and opaque; if of firmer consistence, it
lodges in the lower part of the chamber, but changes its position, and
mixes partially with the humour, on the head being moved; when dense
and curdy, it remains separate from the humour, and its position is not
altered by motions of the head.
During the progress of the inflammatory action, all the symptoms
increase; the pain shoots to the top of the head, and is much
aggravated by pressure on the eyeball. Of course vision is materially
impaired. Constitutional disturbance always accompanies the affection,
and exists in a greater or less degree according to the extent of the
disease. The iris may be primarily affected, but the other textures,
both external and more deeply seated, too often become involved; and
in aggravated cases the whole eyeball suffers. When the most internal
parts, as the choroid coat, the retina, and the vitreous humour, are
affected, sudden and bright flashes of light disturb the patient,
whilst vision is rapidly lost, and for ever. Occasionally the intense
over-action terminates in suppuration of all the affected textures, and
the eyeball soon becomes completely disorganised.
In _Rheumatic Ophthalmia_ the appearances of the diseased eye are
similar to those in ophthalmia produced by any other cause. But the
affection is accompanied with, and seems to arise from rheumatic
diathesis. There is pain in many of the joints, and frequently in the
scalp and portions of the face, increased on hanging the head, and by
pressing the parts. The pains are remittent, supervene at night, and
subside in the morning. In general the ophthalmia is external; but
in severe cases the internal parts become affected, and the eye is
sometimes lost by giving way of the cornea.
Internal ophthalmia is often occasioned by wounds inflicted either
accidentally or by operation. Laceration of the iris in the extraction
of cataract, or an improper performance of the operation for cataract
with a needle, is by no means an unfrequent cause of the affection.
Iritis often occurs during the exhibition of mercury in undue
quantities, and is said also to be a symptom of syphilitic taint. It
is, in many cases, preceded by cutaneous eruption, and seems to be the
consequence of the eruption being repelled, or interfered with in its
progress.
_Choroiditis._—The choroid membrane is sometimes primarily affected:
but more frequently the inflammation of this tunic is the consequence
of sclerotitis, or the disease last described. When the result of the
former cause, it generally takes on the rheumatic type. The early
symptoms are zonular redness of the sclerotic, accompanied by a general
impairment of vision, so that the patient expresses himself as if
looking through gauze or some dark network. Presently the sight becomes
more and more impaired, until a complete amaurosis results. The pupil
is generally in a semi-dilated state, and, instead of presenting the
intense black hue of the healthy eye, it reflects a greenish-grey
colour, dependent upon the effusion of a turbid fluid between the
choroid and retina. The nervous structures, becoming thus pressed
upon, lose their sensibility to light, and are paralysed. This form of
inflammation is generally chronic, and imperceptibly advances to the
iris anteriorly, and to the retina within; the ultimate termination
being complete glaucoma. Various dull and heavy pains accompany
this affection; and, in the latter stages, acute circum-orbitar
neuralgia is the most distressing concomitant. By long-continued
chronic inflammation the sclerotic coat appears to lose its powers
of resistance—the accumulating fluid pushes before it the weakened
tunic, and _Staphyloma Scleroticæ_ is produced. This protrusion of
the external tunic sometimes takes place in various parts, and to a
considerable extent, so that the figure of the globe is entirely lost.
The thinning of the sclerotic at these points allows the dark hue of
the choroid to shine through, and this, together with the bunched-like
appearance of the protruded portions, has entailed upon it the name of
_Staphyloma Racemosum_.
[Illustration]
_Treatment._—In the first stage of internal ophthalmia, active
treatment, properly conducted, should be successful in averting
the progress of the disease; in the latter stages, there is every
chance of vision being entirely lost. The treatment must be actively
antiphlogistic, consisting of general and local bleeding, the internal
use of purgatives and antimonial medicines, and strict abstinence. A
free use of mercury internally is said to check the disease, and, in
its advanced stages, to procure absorption of effused lymph. But the
inflammation can be subdued without the aid of that mineral, though its
effects are often powerful; and a recollection of the bad effects which
are so apt to follow its employment renders a prudent surgeon cautious
in having recourse to it. Mercurial ointment, with opium, rubbed on
the forehead, immediately above the affected eye, gives great relief.
The same relief follows friction with oil, in which the muriate or
other salts of morphia is dissolved. When the incited action declines,
the extracts of belladonna, hyoscyamus, or stramonium, rubbed on the
eyelids and brow, procure dilatation of the pupil, and thereby tend to
prevent its further contraction; but whilst acute inflammation exists,
the pupil is not dilatable; and it is consequently an encouraging
symptom when the pupil begins to yield to the influence of these
medicines. In hypopium it is sometimes necessary to evacuate the pus
when effused in large quantity, in order to prevent the injurious
effects that its pressure might occasion; but, if the quantity be
small, there is a good chance of its being removed by absorption.
In suppuration of the eyeball, whilst the other eye remains sound,
it may be prudent to open the cornea, and allow a free exit for the
matter, in order to prevent the healthy eye from becoming affected.
In the staphyloma of the sclerotic coat, when the eye, as it were, is
affected by a sort of chronic dropsy, (and this disease is met with
at various periods of life,) the tension and bulk of the organ may be
diminished by occasional puncture. The opening may be kept pervious by
the introduction of a conical probe from time to time. I have more than
once introduced a silk thread through the most dependent and prominent
part of the globe with good effect. The organ ultimately shrinks.
_Amaurosis_ implies an impairment of vision more or less complete,
arising from disease in the brain, in the optic nerve, or in the
retina, whether consisting of change or destruction of structure, or
derangement of function. Vision may be diminished or lost by organic
disease in the coats or humours of the eye, or by morbid formations
in the orbit; but to such the term Amaurosis does not strictly apply.
But, after establishment of the disease, other textures of the eye may,
and often do, become affected. Usually one eye at first is amaurotic;
but the other soon participates, and ultimately vision is impaired or
entirely lost in both. The disease may occur idiopathically, or be
symptomatic of other affections.
The general symptoms of amaurosis are the following. Headache is felt
for some time, either constant, or, as is most commonly the case,
occasional, and most severe in the forehead: in many cases the pain
is at times most excruciating. The eyesight gradually becomes weak;
distant objects are unusually obscure, or not at all observed; and
those which are near cannot be accurately discerned. For a short
time vision may seem to be restored, but soon it diminishes more and
more, all objects seem to be enshrouded in a mist, at first thin and
shadowy, but gradually becoming opaque and impenetrable; or a feeling
is communicated of a dark network obstructing the view. Unnatural
impressions are made on the retina; flashes of strong light, or
luminous sparks, appear to dart across the eyes; darkened spots are
seen where none exist; gnats, flies, or other minute bodies, various
in colour and brilliancy, seem to flutter before the face; or a single
dark speck intercepts the vision. Usually the pupil is dilated and
the iris insensible to the stimulus of light; and the former has not
its natural translucent aspect, but is dull and cloudy. But the state
of the pupil cannot be accurately determined in amaurosis, for not
unfrequently it is much contracted, and in many cases the iris retains
both its natural appearance and the full exercise of its functions.
The disease either advances to complete blindness, or stops in its
destructive progress, leaving the patient with vision impaired to a
greater or less degree. When the disease is established, pain in the
head and eyes usually either ceases quickly and entirely, or gradually
abates.
Amaurosis is sometimes temporary, occurring at regular intervals; and,
during its accession, it often varies in intensity. With some patients
strong light is intolerable, and vision is best in the twilight;
others court sunshine, finding their eyesight thereby much improved;
accordingly the former are said to labour under nyctalopia, the latter
under hemeralopia. Some can discern the shape of objects, but either
have no perception of the colours, or mistake the individual colours;
others not only see all objects indistinctively, but conceive them
distorted, double, or extensively multiplied: in some one-half of the
object looked upon is obscured—and frequently there is strabismus, in
consequence of the paralysis being only partial.
Organic amaurosis (that depending on organic disease) may arise from
the change of structure consequent on inflammatory action in the
retina, whether chronic or acute—from atrophy of that membrane and of
the optic nerve—from extravasation into the substance of the nerve, or
compression of it by morbid formations—from softening or suppuration
of the nerve and its connexions—or from various diseases of the
encephalon. Functional amaurosis may proceed from temporary plethora
about the optic nerve and retina—from intense and long continued
use of the organ—from derangement of the digestive apparatus—from
general debility, however induced—from excessive influence on the
system of poisons or powerful medicines—from concussion of the nervous
and cerebral substance, or from long continued irritation in the
neighbourhood of the eye. Amaurosis may also follow injuries of various
kinds.
In the treatment of organic amaurosis but little can be done, and that
little is unsatisfactory. In the functional form, however, vision
may be improved, if not wholly restored, by removal of the exciting
cause, and the carefully avoiding of such circumstances as seem to
predispose to the affection. After due constitutional treatment,
considerable benefit is often derived from counter-irritation;
and I have in many cases witnessed the good effects of blistering
the temples and besprinkling the raw surface with the powder of
strychnine,—a practice very far from nugatory. On removing the blister,
the cuticle and lymphatic effusion beneath are carefully scraped
away, and from one-eighth to one-half of a grain of the powder dusted
over the exposed cutis. The sprinkling is repeated daily, and the
dose gradually increased. When the surface dries, a fresh blister
is applied, and the use of the powder resumed. It may be employed,
when gradually increased, to the extent of two grains on each temple;
but, if spasmodic twitchings and constitutional disturbance begin to
show themselves, it must be immediately abandoned, and not resumed
till after some days, and even then in diminished doses. In not a few
cases, both of complete amaurosis, and of vision impaired to such an
extent that the patient could merely distinguish light from darkness, I
have by this practice succeeded in restoring the sight completely; in
others, vision has been very much improved. Still, by far the greater
number of amaurotic patients are incurable; and even those who have
derived benefit from strychnine are, I am strongly inclined to suspect,
exceedingly liable to relapse.
In the treatment of functional amaurosis, it will be necessary to
investigate minutely the causes on which the defective vision may
depend. Thus we may find a congestive state of the retina or brain,
arising from suppressed natural discharges, as the menstrual flux,
or the sudden suppression of habitual but morbid discharges, as the
healing of an old ulcer, &c.
Again, amaurosis maybe the result of irritation in some portion of the
alimentary canal, as from the presence of worms. Patients who have long
laboured under imperfect amaurosis have occasionally been suddenly
relieved by the discharge of a tape-worm. Difficult and painful
dentition in children not unfrequently gives rise to this disease.
Hence the treatment of functional amaurosis will necessarily vary with
the cause; and no general rule can, with any propriety, be laid down as
to our selection of remedial measures.
_Glaucoma_, or green cataract, is a disease of the hyaloid membrane
and vitreous humour, probably depending on a varicose state of the
bloodvessels. The pupil is usually dilated, irregularly oblong, the
iris being narrowed towards the upper and inner side. There is a
dull shining appearance at the bottom of the eye, not fixed as in
cataract, but varying according to the position of the light. The lens
becomes opaque and greenish as the disease advances, vision gradually
diminishes, and the iris is immovable. After sight is lost, the patient
has a perception of a luminous appearance in the organ when pressed
upon. Both eyes are generally affected, one after the other; headache,
often violent, attends the disease; many remedies, both external and
internal, may be tried on recommendation, though without effect: the
disease seldom, if ever, admits of cure.
_Of Cataract_, or opacity of the crystalline lens and its capsule,
attended with partial loss of vision.—The disease is, in general,
gradual in its progress: but sometimes it advances rapidly, as when
occasioned by a blow or wound. When slow, the opacity commences in the
centre of the lens, and extends gradually towards the circumference.
Before any change can be perceived in the organ, the patient sees
objects as if covered with a mist or veil; and, as the opacity becomes
distinct, vision is gradually impaired. During the day, vision is very
indistinct, as the pupil is contracted, and the rays of light reach
the retina only through the opaque centre of the cataract. But during
twilight vision improves, as then the pupil becomes dilated, and
admits of transmission of light through a portion of the transparent
vitreous humour, as well as through the semi-opaque margins of the
crystalline lens: for a similar reason, it is also more distinct after
the application of belladonna or hyoscyamus either to the eye or to
its neighbourhood. In the ordinary state of the parts, a clear black
ring is often visible around the opacity, either from the margins
of the lens being unaffected, or from the posterior surface of the
pupillary portion of the iris being pushed forwards by enlargement of
the lens. Patients, having become aware of the great improvement of
vision caused by dilatation of the pupil, are often contented to use
narcotic remedies externally, so long as they retain their dilating
influence—and, strange to say, they do not soon lose it—instead of
submitting to any operation. As cataract advances, even luminous bodies
cannot be accurately distinguished, though the situation from which the
light proceeds is perceived; thus the patient in a clear light may have
an indistinct perception of a candle or window, and in some cases even
of the bars of the window. The motions of the iris are not affected,
unless, in rare cases, when the cataract is large and compresses the
iris; or when the functions of the third pair of nerves have been
in any way impaired; or when the iris has been the seat of acute
inflammation.
Cataract may be confounded with other diseases of the eye, as with
amaurosis. But, in amaurosis, opacity, when it exists, is deep,
concave, greenish, or of a metallic appearance; whereas, in cataract,
it is of a more or less white colour, convex, and situated immediately
behind the pupil.
Cataract may be _lenticular_ only, the lens being opaque whilst its
capsule remains transparent. In such a case the disease is slow in
its progress, and the opacity uniformly commences in the centre of
the lens, and gradually extends to the circumference. The degree of
opacity varies in different cases, from cloudy dimness to complete
whiteness. In general the predominant hue is white or greyish, but not
unfrequently the opacity is of several colours, and occasionally of a
mottled appearance. The consistence also of lenticular cataract varies,
being sometimes fluid, occasionally extremely dense and almost osseous,
but most frequently of caseous consistence. When fluid, the cataract is
of larger size than the healthy lens; when caseous, the part usually
retains its former dimensions; and when dense, the lens is often
considerably diminished in size. The motions of the pupil are seldom,
if ever, affected.
Cataract may be entirely _capsular_, the capsule being opaque, whilst
the lens either remains free of disease, or has been removed by
natural or artificial processes. The opacity in this case does not
always commence in the centre, but frequently begins at the margin, and
is of a spotted or mottled appearance, and in general not uniformly
opaque. No black ring around the opacity is observed, though the
pupil be dilated; and the motions of the iris are sometimes slow. The
opaque spots are said sometimes to move when the position of the head
is changed. The anterior portion of the capsule, the posterior, or
the whole, may be affected; but the anterior is the part which most
commonly becomes opaque in the first instance.
In many cases both lens and capsule are affected; and then the cataract
is termed _capsulo-lenticular_. Occasionally the diseased lens, in such
circumstances, is of fluid consistence; and in many cases is spotted.
Portions of lymph, organised or not, lodged in the posterior chamber,
have by some been termed _spurious_ or _adventitious_ cataract; since,
when the pupil is shut by such effusion, the appearances presented are
somewhat similar to those caused by opacity of the lens, or of its
capsule. Such deposits, however, can readily be distinguished from true
cataract, being in general of a yellowish colour, in close contact with
the posterior surface of the iris, and, when organised, often streaked
with red vessels. Generally, too, the pupil is irregular from adhesions
between the lymph and the pupillary margin of the iris.
Cataract would, in some cases, appear to be hereditary,[27] and
frequently it is a congenital affection. In very young children it
may be caused by imprudent exposure to strong light. In adults it
often seems to be produced by the action of strong reflected light,
as by exposure to intense fires in forges, glasshouses, &c., or by a
dependent position of the head, accompanied with exposure to light.
People advanced in life are most subject to the disease.[29] It is not
an unfrequent consequence of internal ophthalmia, and almost invariably
follows the slightest wound or most delicate puncture of the lens: it
often occurs after slight injury of the lens or its capsule, inflicted
during attempts to form an artificial pupil. Cataract may occur rapidly
from extensive dilatation of the lenticular vessels; or from such
an injury of the eye as causes laceration of the vessels supplying
the capsule and lens, detaches them from their other connexions, and
consequently leaves them without a nutritive source.
Cataract sometimes, though rarely, disappears spontaneously, being
absorbed; but most frequently an operation is required to remove the
opaque body from the axis of vision, though no hurry is necessary
in having recourse to it. The chance of success from operation must
depend very much on the state of the different parts of the eye, on
the kind of cataract, and on the state of the constitution. Many
remedies, external and internal, and mercury amongst the rest, have
been employed with the view of dissipating cataracts; but all are
of no use. An operation, of one kind or another, only can be relied
on. And still, even in favourable cases, and in the best hands, the
contingencies attending operation are so great, that success cannot be
absolutely promised or expected. The mode of operating, and the kind
of operation, must be varied according to circumstances; and great
experience is required to determine the proper course of procedure
in each case. Steadiness is absolutely necessary both in the patient
and the operator, in order that the proceedings may be carried to a
happy conclusion. The operator must have a good eye; a steady, light,
and skilful hand; a fine touch; courage and caution—qualifications
necessary in all surgical operations, and in none more so than in those
on the eye.