of the lids and chemosis of the bulbar conjunctiva, and occasionally
gives rise to an orbital cellulitis which by its effects on the optic
nerve impairs or destroys sight. Beer[167] speaks of an idiopathic
erysipelatous conjunctivitis which may not be accompanied by swelling
of the lids. The conjunctiva is of a pale, somewhat livid-red hue, in
which no distinct vessels are visible, there being numerous bright-red
ecchymotic spots in the subconjunctival tissue. Vesicular prominences
form around the cornea, and become so large as to project between the
lids. The folds and interstices of this swollen membrane are covered
with thin mucus, which often adheres so closely to the cornea as to
make it look hazy, but which can be washed off, leaving the corneal
surface as brilliant as in its normal state. The conjunctival swelling
finally subsides, and the membrane again adheres to the sclerotic. Even
after there is apparent absorption of the ecchymoses, the places where
there were extravasations of blood are slow in adhering to the sclera,
and often roll into folds with every motion of the eye. Mackenzie
describes the conjunctiva as of a pale yellowish-red color: it rises in
soft vesicles around the cornea, and these change in shape with every
motion of the eye. There is slight photophobia and a pricking
sensation, with a large quantity of white mucus, which is secreted by
the conjunctiva and the Meibomian glands. Where a low grade of orbital
cellulitis ensues we may have only slight prominence of the eye and
some interference with its motions, in which a complete subsidence of
the symptoms without any failure of eyesight may take place. We may
encounter more severe cases, where the intense swelling and
inflammation of the orbital tissues so impair the functions of the
optic nerve and retina as to permanently destroy the eyesight, and at
times destroy life by the extension of the inflammation to the
meninges. The cellulitis may attack one or both orbits. Poland[168] has
recorded a case of protrusion of both eyes where, after death, the
ophthalmic veins and the cavernous sinuses were found full of pus;
while Cohn[169] has reported another fatal case of double erysipelatous
cellulitis, in which post-mortem showed purulent phlebitis of the orbit
and brain with embolic infarcta in the lungs. All cases of double
exophthalmos from erysipelas do not end as fatally: Jaeger has recorded
two cases of recovery, where in each one eye remained permanently
blind, while the other was restored to sight. He has given us accurate
and beautiful ophthalmoscopic plates of the {770} lesions in the blind
eyes, these plates showing atrophy of the optic nerve, with great
thickening of walls of the retinal vessels, which in some places
totally hide their contents, while in others the blood-columns are
still faintly visible. In one case the inflammation of the lids had
been so severe that they had grown together in the middle of the
palpebral fissure and had also formed an attachment to the eyeball.
These cicatricial bands were divided with the knife, only to find a
blind eye with dilated pupil. In one of Jaeger's cases there were
pigment-masses in the choroid. Coggin[170] describes a case of double
exophthalmos with blindness where the corneæ were so denuded of
epithelium that no ophthalmoscopic examination was practicable. Three
weeks later the media were clear and the discs atrophic, the vessels
being visible as empty white cords. These effects be attributed to
thrombosis. Knapp[171] has recorded a most interesting case of
erysipelas where there was severe fever with high temperature (104.8°)
and marked protrusion of both eyes, in which he had an opportunity of
observing the eye-grounds in all stages of the disease. On the ninth
day ophthalmoscopic examination showed that the yellow spot and disc
were both invisible, and that their localities could only be determined
by the radiation of the tortuous veins, which were gorged with blood so
dark as almost to be black, the retinal arteries being invisible. The
posterior portion of the eye-ground was milky white, while the anterior
was reddish white: numerous hemorrhages were scattered through the
retina, more or less linear in shape in the posterior part and
irregularly rounded in the anterior portion. Two days later the orbital
swelling was less, and the arteries were visible, though much reduced
in size, and the eye-ground was beginning to resume its normal color.
About a month after seizure the patient was convalescent and he could
go out. At this time the disc was atrophic, and there was a whitish
cloud in the region of the yellow spot, with numerous hemorrhages: both
arteries and veins presented isolated areas of perivasculitis,
accompanied by snow-white patches of greater or less extent, which were
of the same calibre as the adjacent dark-red blood-columns in each of
them. Two months later, the disc was still atrophic, the hemorrhages
had been absorbed, the blood-vessels were mostly visible as white
cords--one of them presenting the usual appearance, while two showed
blood-contents for a short distance surrounded by dense white walls.
The white intercalary portions of the vessels seen in the examination
two months after the onset of the disease are considered by Knapp to be
thrombi. Arlt, Jr., reports a case of gangrenous erysipelas of the lids
with loss of the eye, and mentions that his father had seen several
similar cases.
[Footnote 167: J. J. Beer, _Lehre von den Augenkrankheiten_, vol. i.
398, 399. (He also gives a colored plate of the appearance, Taf. 1, p.
3.)]
[Footnote 168: _R. L. O. H. Rep._, vol. i., pp. 26-31, 1857.]
[Footnote 169: _Klinik der Embolischen Gefärskrankheiten_, 1860, p.
196.]
[Footnote 170: D. Coggin, _Trans. Amer. Oph. Soc._, vol. ii. pp.
570-572 (session 1878).]
[Footnote 171: _Trans. Amer. Oph. Soc._, 1883, and _Arch. of
Ophthalmology_, 1884 (with plates and lithographs).]
* * * * *
{771} DISEASES OF THE NERVOUS SYSTEM.[172]
[Footnote 172: In the foregoing sections the relationship between
definite diseases and their concomitant eye symptoms have been dealt
with; whereas in this division of the subject this has been found so
impracticable that it had to be discarded in favor of an anatomical
basis upon which to place the various affections. This change has
necessitated the disuse of the representative headings of names of
disease, and the substitution of absolute physical conditions with
their hypothetical causes.]
Symptoms of impaired function in the eyes and their appendages have
always been regarded as valuable indices of disease of the nervous
system; and when it is considered that six of the twelve pairs of
cranial nerves send branches to these organs, and that the second,
third, fourth, and sixth pairs are distributed exclusively to them, and
that they are further supplied with twigs from the cervical and
cerebral sympathetic nerves, it can be readily appreciated that a vast
variety of nerve lesions, interfering with some of these connections
either at their origins or in their course, may produce either impaired
vision in the eye or loss of power in some of its appendages. Moreover,
the retina and optic nerve originate as sprouts from the anterior
cerebral vesicle, and retain respectively the structure of a ganglion
and of a cerebral commissure. From these circumstances, as well as from
the close connection of their blood and lymph circulations with those
of the cerebrum, they frequently become delicate exponents of
intracranial changes.
Affections of the Second Pair (Nervi Optici).
NEURITIS.--Five years after the discovery of the ophthalmoscope Graefe
called attention to the fact that in many cases of intracranial disease
the intraocular ends of the optic nerve presented marked changes. He
had already discovered that when these changes were inflammatory in
character they presented two main varieties--the one in which there was
intense swelling of the intraocular end of the nerve (designated by him
stasis papilla); and the other, in which there was a dull-red suffusion
of the disc. In the first variety, which he attributed to increased
intracranial pressure from tumor or other cause, the disc projected
into the eye and formed a small tumor, often prominent to an extent
equal to its own diameter, the oedematous and opaque nerve-fibre being
permeated by tortuous, enlarged, and often newly-formed capillary
vessels, which hide the arteries and allow only the projecting branches
or lips of the tortuous and dilated retinal veins to be perceived as
they slope down in the swollen papilla to regain their normal level in
the retina; the other, which he thought was due to meningitis spreading
along the nerve, was characterized by a slightly swollen disc of a
dull-red color, with opacity of its nerve-fibre sufficient to
completely hide its normal boundaries, associated with tortuous veins
and arteries that were often diminished in size. Since that time
volumes have been written on the subject, and it has given rise to most
extended and searching discussion, causing researches to be instituted
which have added much to the knowledge of the anatomy and pathology of
the central connections, circulation, and lymph-supply of the optic
nerves. To-day the first variety is usually designated {772} as choked
disc or papillitis, and the second as interstitial or descending
neuritis. When typical cases are seen at the height of the disease, it
is easy to make a distinction between the two varieties, but usually
they shade off so imperceptibly, the one into the other, and the
consecutive atrophies present so absolutely the same appearance, that
no experienced observer would at all times claim an ability to
distinguish between them. In the choked disc the intense swelling is
limited to the intraocular end of the nerve, and therefore vision is
little interfered with until the swelling becomes so great, or the
contraction of the subsequent cicatrization so decided, that by
pressure on the nerve-fibre they become atrophic and incapable of
reporting the retinal image to the brain-centres, while in interstitial
neuritis, owing to the primary interference with conduction, vision is
impaired from the beginning. The choked disc usually develops slowly,
requiring a period varying from a few days to two, three, or four weeks
to attain its maximum, and it may exist unchanged for a long time
before atrophy sets in. The writer once had an opportunity of observing
a case in which the choking was produced by a cerebral gumma, and where
for nearly a year the discs remained swollen and vision was still 6/8;
and another of intense swelling, where the discs projected at least
from one and a half dioptrics (one millimeter), in which for a period
of three months vision was 6/6 and the field almost normal.
Mauthner,[173] Blessig, and Schiess-Gemuseus[174] each record cases of
marked choking of the discs lasting for some time, where the patients
retained perfect central vision to the day of their death. Double
choked discs are almost always a symptom of grave intracranial disease
when all local causes in the eyes or orbits have been excluded. Even in
the very exceptional cases where they form part of the symptoms of
Bright's disease they are probably indicative of intracranial effusion.
The lower grades of inflammation of the optic nerve are apt to be
accompanied by marked proliferation of the connective tissue between
the nerve-bundles. There are many cases of congestive atrophic change
of the optic nerve where at first central vision is but little
affected. In judging of the appearance of neuritis the observer should
be sufficiently familiar with the changes in the eye-grounds of healthy
individuals which occur from local causes not to allow himself to be
led astray by the often very decided neuro-retinitis constantly
encountered in hard-worked eyes with uncorrected astigmatism and slight
degrees of ametropia; and not to mistake these changes, which are
simply an expression of that local congestion which leads ultimately to
softening and elongation of the eyeballs, for changes due to incipient
cerebral disease, although each is accompanied by neuralgia. While,
after careful study of the various forms of neuritis optici during the
last few years, it is acknowledged that increased intracranial pressure
is apt to cause choking of the disc, and that basilar meningitis
frequently gives rise to interstitial neuritis, we are still far from
having such a clear comprehension of the subject as to render the
profession unanimous as regards its pathology; some observers claiming
that choked disc is essentially a vaso-motor paralysis of the affected
part, while others maintain that it is caused by infiltration of the
disc and optic nerve with abnormal fluids which have been secreted
within the cranium, and by increased intracranial pressure have been
{773} forced between the sheaths of the optic nerve and between it and
its pial envelope. The ingenious explanation proposed by Graefe, that
stasis papilla is produced by the damming up of the return blood in the
cerebral sinuses, thus causing impeded circulation with increased
blood-pressure in the ophthalmic vein and its branch (the central
retinal vein), has generally been abandoned since the investigations of
Sesemann and Merkel have demonstrated the free anastomosis between the
facial and the orbital veins in whatever method the primary congestion
may be brought about. The latter part of his explanation, in which he
compared the rigid tissue of the lamina cribrosa to a multiplier, by
its construction tending to augment any existing plethora in the head
of the nerve, is still worthy of consideration. While the theory of
vaso-motor paralysis is a most enticing one, it is, however, difficult
to understand why paralysis of any of the fibres of the sympathetic
should always be accompanied by such a limited local congestion without
affecting the retinal tissue in their peripheral parts or without any
branch leading to the iris, ciliary body, or choroid. Granting that
there is some special filament of the carotid plexus distributed to
this region of the nerve, it is hard to comprehend how it can be acted
upon by tumors of almost any size or consistence situated in the most
varied parts of the brain, and also why pressure on the various
portions of the intracranial nerve, chiasm, and optic tracts (which so
frequently cause hemianopia and partial atrophies) should not be
associated with choking of the disc.
[Footnote 173: _Ophthalmoscopie_, p. 293, 1868.]
[Footnote 174: _Klinische Monatsblätter f. Augenheilkunde_, 1870, p.
100.]
THE LYMPH-SPACE THEORY--Since the anatomical researches of Schwalbe and
of Retzius have given us a clear understanding of the lymphatic
circulation in the eye, the effusions into the sheaths of the optic
nerve that have been found in many cases of choked disc that have been
examined post-mortem have been shown to be due to the effects of
blocking up of the lymph-channels and of the effusion of cerebral
fluids (lymph-pus and blood) in the intervaginal space of the nerve or
between it and its pital sheath. In support of this, Manz in 1870
showed that injection of fluid into the cranial cavity of rabbits would
produce a marked neuritis which was readily demonstrable by the
ophthalmoscope; while Schmidt proved that the spaces of the lamina
cribrosa of the optic nerves of the calf could be distended by fluid
thus injected. In experiments on the human cadaver the writer has
repeatedly seen that colored fluids could be readily driven between the
sheaths of the optic nerve by injections from the subarachnoid and
subdural spaces, and also that when high pressure was used and the
injection made directly into the intravaginal space of the nerve, the
fluid found its way from the subdural into the perichoroidal space. He
once obtained traces of the colored fluid in the lamina cribrosa of the
nerve. Since this mode of communication between the cavity of the
cranium and the eye has been duly appreciated, a large number of
autopsies have shown that choking of the disc has been accompanied by
dilatation of the outer sheath of the nerve by lymph-pus or blood which
has found its way down from the cranial cavity. It has also been
demonstrated that proliferation of the intravaginal (arachnoid) tissue,
and the formation of tumors (psammoma and tubercle) at the distal end
of the nerve will produce choking of the disc by causing local
accumulations of fluid. On the other hand, there are cases where this
distension of the sheaths has been {774} carefully looked for and not
found; and those who hold the _vaso-motor theory_ consider that it is
in any case an accompanying accident, and not the cause, of the choking
of the disc. The experiments of Rumpf and Kuhnt, however, add to its
probability, by which the deleterious influence of lymph on the
axis-cylinder of nerves adds to the probability of the above theory;
moreover, even if it is granted that this accumulation of lymph or
other fluid within the sheaths of the optic nerve is the cause of
choking of the disc, it seems very unreasonable to the writer to expect
to find it in all stages of the complaint. It is everywhere admitted
that a cerebral tumor may exist for a long time without causing
papillitis, and also that inflammation of the discs may exist for
months or years, until they have become entirely atrophic, before the
brain disease shall have caused death. Choking of the disc is
essentially a temporary symptom. Although severe cerebral irritation
may cause a great transient increase of cerebro-spinal fluids, which in
their turn may produce the most intense inflammation of the intraocular
end of the nerve, yet when the atrophied nerve comes to be examined
months or years later they leave no traces sufficiently lasting to
positively prove their previous existence. Whatever theory may be
adopted as to the mode of production of optic neuritis, its clinical
importance is admitted by all. Where it exists on both sides, and is
accompanied by other cerebral symptoms, it usually points to increased
intracranial pressure.
Since the earliest times, impaired vision and other ocular symptoms
have been recognized as accompaniments of diseases of the brain. In
more recent, but still preophthalmoscopic, times the statistics showing
the percentage of blindness in brain tumor are most interesting: thus,
Abercrombie noted failure of vision in 17 (38-5/10 per cent.) out of 44
cases, while Ladame, in a study of 331 cases, estimated that there is
disturbance of vision in about 50 per cent. This percentage represents
the cases of atrophy consequent upon neuritis only. It must be
remembered, however, that many die of the brain disease while the disc
is still choked, and that this state of the eye-nerve may exist for a
long time without any appreciable failure of vision, making it evident
that should we look for choked disc with the ophthalmoscope while there
are as yet no symptoms of failing sight, the above percentages would
still be higher. In support of this we find that there is a rise of
double optic neuritis to 93 per cent. in a series of 88 cases of brain
tumor, 43 of which have been recorded by Annuske[175] and 45 by
Reich,[176] these being here adduced because in all of them there was a
careful ophthalmoscopic examination. Gowers thinks that this is an
over-estimate, but admits that optic neuritis occurs in four-fifths (or
80 per cent.) of all cases of cerebral tumor. In considering this
question we cannot too carefully keep in view the facts so well stated
by Hughlings-Jackson,[177] that optic neuritis is essentially a
transient symptom, and that, although it often occurs early in the
disease, it may in some cases be developed only in the latter stages of
the complaint. Jackson states that he frequently examined a case with
the ophthalmoscope in which there was no appearance of choked disc till
six weeks before the patient's death, when marked papillitis developed,
the {775} autopsy showing a tumor in the left cerebral hemisphere. In
fact, where the tumor does not occupy the cortical sight-centres, the
intercalary ganglia, or press on the tractus opticus or chiasm, it may
exist a long time without producing any affection of the optic nerve or
deterioration of vision. No neuritis will take place by increase of
intracranial pressure so long as the growth of the tumor is slow and
there is a corresponding absorption of brain-substance; but should the
growth of the tumor be rapid, or any other cause exist by which
increased pressure, with consequent irritation and effusion, would take
place, infiltration of the nerve and its sheaths with lymph or
inflammatory products would ensue, and give rise to swelling and
increased growth of connective tissue. In cases of cerebral tumor,
however, and where the growth presses on the intracranial portion of
the optic nerves, or where the chiasm is compressed and atrophied by
the protuberant and bulging floor of the third ventricle, as in the two
cases recorded by Foerster,[178] optic atrophy may be produced without
the occurrence of previous choked disc.
[Footnote 175: _A. f. O._, xix., 3, pp. 165, 300.]
[Footnote 176: _Klin. Monatsblätter f. Augenheilkunde_, 1874, pp. 274,
275.]
[Footnote 177: _Med. Times and Gazette_, Sept. 4, 1875.]
[Footnote 178: _G. u. S._, vol. vii. p. 141.]
HEMIANOPIA (HEMIOPIA, HEMIANOPSIA).--We may, however, have serious
affections of the sense of sight without any marked alteration in the
retina or optic nerve. Careful study of the various forms of hemianopia
and other symmetrical defects in the field of vision will often
surprise us by the extent of the defect which it reveals, and sometimes
serve as a guide to the localization of the cerebral lesion which
produces the defect. Hemianopia (or the not-seeing of half an object)
is usually of the homonymous lateral variety, in which, if the centre
of any object be fixed by the macula lutea of each eye, then either all
parts of the object lying to the right-hand side of the points of
fixation or else all parts lying to the left of that point become
invisible. There may also be temporal hemianopia (hemianopia
heteronymous lateralis),[179] in which the nasal side of each retina is
blind, and the temporal field of each eye consequently abolished. In
such case the right eye sees nothing to the right of the
fixation-point, and the left eye nothing to the left of it. The
external half of each retina may be blind, in which case there is loss
of the nasal field of each eye and of the entire binocular field of
vision. In all of these cases the dividing-line between the blind and
seeing parts of the retina is a more or less vertical one, but there
are also cases where the dividing-line is horizontal, and we thus have
an upper or lower hemianopia. From a clinical standpoint the
first-named variety (homonymous lateral hemianopia) is markedly
distinguished from the others by its usual more rapid development, and
by the absolutely sharp dividing-line which runs vertically through the
retina at the macula; this field of vision retaining its form without
subsequent development of zigzags or other irregularities. All other
varieties of hemianopia develop more slowly, and their
boundaries--which are usually not perfectly vertical or horizontal, and
do not generally extend to the fixation-point--may vary from time to
time. The homonymous lateral variety is of far more frequent occurrence
than the other forms: out of 30 cases carefully observed by Foerster,
where perimetric measurements {776} of the fields were taken, 23 were
of this variety, while the remaining 7 presented the heteronymous
temporal form. The subject of homonymous lateral hemianopia is so
important clinically, and so interesting as regards the probable course
of the fibres in the optic nerves, chiasm, and cerebral centres, that
it appears desirable to state briefly a few of the most decisive facts
in regard to it which have been substantiated by careful autopsies.
[Footnote 179: If we retain the word hemiopia (half-seeing), then this
variety is termed medial hemiopia, because the lateral halves of the
retina are still intact and vision is practicable in the median or
nasal field of each eye.]
1. In 1875, Hirschberg[180] published a case of right-sided homonymous
hemianopia with perfect central vision. At first there was no paralysis
of sensation or motion, but subsequently aphasia and right hemiplegia
set in. The autopsy showed a large sarcomatous tumor which had caused
atrophy of the left tractus opticus.
[Footnote 180: _Virch. Arch._, Bd. lxv.]
2. Hughlings-Jackson and Gowers[181] (1875) relate a case of left
homonymous hemianopia with hemianæsthesia and hemiplegia of the same
side. The autopsy showed softening of the posterior part of the right
thalamus opticus without other lesion.
[Footnote 181: _R. L. O. H. Rep._, vol. viii. p. 330.]
3. Curschmann[182] (1879) gives the case of a patient who drank
sulphuric acid, which corroded the oesophagus and affected the aorta,
causing embolus of the right brachial artery. On the day following
there was complete left hemianopia. The autopsy showed a large area of
cerebral softening in the right occipital lobe without other lesions.
In the discussion of this case at the session of the Berlin Society of
Psychiatry and Nerve Diseases, Westphal[183] related a case of
unilateral convulsions without loss of consciousness where there was
homonymous hemianopia, and in which the autopsy showed a large area of
softening in the white substance of the occipital lobe in the side
opposite to the defect in the field of vision.
[Footnote 182: _Centralblatt f. Augenheilkunde_, 1879, p. 256.]
[Footnote 183: _Loc. cit._, p. 181.]