EMBOLISM 
OF THE 
Central Artery of the Retina. 
By DR. J. SAMELSOHN, of Cologne. 
(Translated by Dr. Hasket Derby, Boston.) 
Reprinted from Archives of Ophthalmology and Otology, Volume III., No. 2. 
NEW YORK: 
WILLIAM WOOD & CO., 27 Great Jones Street. 
1874. EMBOLISM OF THE CENTRAL ARTERY OF 
THE RETINA. 
By Dr. J. SAMELSOHN, of Cologne. 
(Translated by Dr. Hasket Derby, Boston.) 
A case of blindness occurring in connection with the 
chain of symptoms which characterize embolism of the 
central artery of the retina, is still entitled to be re- 
garded with more interest than a single observation in 
most instances is capable to elicit. • For the hope ex- 
pressed by Virchow,* in closing his classical researches 
on thrombosis and embolism, that-" if a chance should 
be offered of making an ophthalmoscopic examination 
in cases of very recent embolism of the larger retinal 
arteries, it might be possible, during life, to distinguish 
the occluded portions by their whiteness and trace 
directly the progress of secondary derangements, all of 
which would have a most valuable bearing on the theory 
of metastasis "-this hope has been only partially real- 
ized. It is true that we are at present in possession of 
a satisfactory though not very large number of observa- 
tions in which the diagnosis of obstruction of retinal 
vessels by embolism is well made out, though unsup- 
ported by anatomical proof.f It is true that Knapp has 
* Gesammelte Abhandlungen, p. 723. 
f Cf. Stellwag v. Carion, Lehrbuch der Augenheilkunde, 1867, p. 791. Roth, 
Ueber Netzhautaffectionen bei Wundfieber. Deutsche Zeitschrift f. Chirurgie, Bd. I. 
Heft 5, P- 471- Embolism of the Central Artery of the Retina. 
45 
recently described * a hemorrhagic infarctus as the 
keystone, so to speak, to the picture of derangements 
in the circulation of the retina caused by embolism ; but 
the analysis and the history of all these observations are, 
in many respects, so varying and even contradictory, 
both in the apparently similar mechanical conditions 
and in the consecutive, nutritive and functional derange- 
ments, that a general description of the disease under 
consideration can only be given with the utmost cau- 
tion, and a diagrammatical explanation of the secondary 
derangements, or an elucidation of the process of metas- 
tasis, has, from this part at least, hitherto been out of 
the question.! It is only since Cohnheim's J recent 
luminous investigations have cleared up the subject of 
mechanical derangements of the circulation succeeding 
arterial embolism, and especially since the vague con- 
ception of collateral fluxion has been reduced to its 
proper proportions, that it will perhaps be possible to 
marshal the numerous variations of the observations on 
record, in obedience to an ordered system, to subject 
the published cases to a more rigid criticism, and to 
find a surer foundation for diagnosis. 
Before, however, I discuss previous observations with 
reference to the results gained by the experiments of 
Cohnheim, I would crave permission to report an origi- 
nal observation, which excited me all the more to this 
investigation by its coincidence with the appearance of 
Cohnheim's work. 
* Archives of Ophthalmology and Otology, Vol. I., I, 1869, 64-84. 
f Steffan,Ueber Embolische Retinalveranderungen,Graefe's Archiv, XII., 1., p. 42. 
£ Cchnheim. Untersuchungen uber die embolischen. Processe, 1872. 46 
J. Samelsohn : 
Maria P., a woman of no especial vigor, 62 years of age, came to 
me, August 2d of this year, complaining that fourteen days ago, after 
passing a quiet night, she remarked in the morning entire blindness of 
the left eye, although she was perfectly certain of having seen well with 
it the evening before. On awaking, she had a feeling as though this 
eye were shut, and consequently asked her husband to take a look and 
ascertain why she could not open it.* Being informed by him that it 
was open, she experimented on the acuteness of vision of each eye, 
and found that with the left she could not even distinguish light from 
darkness. She at once consulted an oculist, who told her there was 
nothing to be done for the eye, that it was lost. Alarmed at this opin- 
ion, she went to another, who ordered her iodide of iron, but said noth- 
ing about her condition; and it was at the end of fourteen days that 
she came to me to obtain my opinion concerning the disease. 
The objective examination showed the following : 
The right eye, emmetropic, has S = 1, and the amount 
of accommodation corresponding to the age of the 
patient. In spite of the normal acuteness of vision the 
patient insists that all objects seem smaller to her than 
formerly. As no comparison with the appreciation of 
magnitude by the left eye could be made, I was unable 
to estimate at its proper value the correctness of her 
statement. This seeing things smaller, however, 
inspired her with much apprehension for the future. 
Ophthalmoscopic appearances normal. 
In the left eye there is a dull quantitative perception 
of light in the eccentric portion of the field lying 
upwards and inwards ; a large lamp being distinguished 
when held close before the eye, while in the central 
and remaining portions of the field entire blindness pre- 
vails. The cornea and iris are unaltered; the pupil is 
* Steffan's patient experienced the same feeling. L. c., p. 36. Embolism of the Central Artery of the Retina. 
47 
moderately enlarged, as in cases of paralysis of the ocu- 
lomotorius, and reacts with extreme sluggishness when 
exposed to light; still, this reaction is independent of the 
movements of the other iris, and is incontestably pres- 
ent. The intra-ocular pressure is perceptibly height- 
ened, albeit to no great extent. 
Ophthalmoscopic Examination. - The transparent 
media are entirely clear, the refraction of the eye emme- 
tropic. On bringing the fundus into focus the attention 
is at once arrested by the threadlike appearance of the 
retinal vessels, it being at first sight impossible to dis- 
tinguish between the arteries and the veins, the reflex 
due to the tubular form of the arteries being wholly 
wanting. On closer examination it is seen that the 
papilla has clean-cut edges, is surrounded by no retinal 
cloudiness, and is tolerably pale, but still by no means 
exhibits the dazzling whiteness of atrophy. The pale- 
ness here described is all the more marked by the sharp 
contrast it offers to the normal redness of the fundus. 
The veins emerge with narrowed channel from the vas- 
cular centre of the papilla, and gradually increase in 
diameter as they approach the periphery, but even at 
the equator attain to scarcely half the thickness of the 
veins seen in the other eye. They convey blood 
throughout their whole course, and exhibit no portions 
free from blood with oscillating movements. The arte- 
ries depart from the point of entrance of the vessels as 
thin, bright-red threads, and become in part brighter, 
but less visible, as soon as they pass beyond the edge of 
the papilla, owing to the lessened contrast between 
them and the red fundus oculi. One artery proceeds. 48 
J. Samelsohn : 
in the inverted image, downwards and inwards, is 
accompanied for a certain distance by a vessel readily 
made out to be a vein, and gives forth a dark-colored, 
spindle-shaped swelling, starting off from the thread- 
like vessel at a distance of about one and a half diame- 
ters of the papilla from the edge of the optic disk; just 
behind this enlargement the vascular canal entirely 
escapes recognition. The most rigid investigation in 
the upright image fails to detect any oscillating move- 
ment in the contents of this vessel. The vein corre- 
sponding to this arterial division is the fullest of any of 
the fundus, and tapers but slightly as it approaches the 
point of entrance of the vessels. The whole extent of the 
macula lutea has a bloody tinge, is 'not surrounded by 
any whitish opacity, does not look like the seat of an 
extravasation, but, on the contrary, seems, in spite of its 
redness, to preserve a uniform granular appearance, and 
keeps its normal line of demarcation from the vicinity 
(it being remembered that the boundaries, at an age 
like that of the patient, are not particularly marked or 
circumscribed) ; it is, however, remarkable that the ves- 
sels, so thin throughout the remainder of the fundus, 
assume such prominence in the region of the macula. 
The strongest pressure on the eyeball excites no arte- 
rial pulsation; the phosphenes are perfect. 
Of the significance of the ophthalmoscopic symptoms 
there could be no question. The sudden advent of 
blindness, the striking diminution in size of the vessels, 
especially of the arteries, the enlargement of the veins 
towards the periphery, the impossibility of exciting arte- 
rial pulsation by pressure, all pointed to a cutting off of Embolism of the Central Artery of the Retina. 
49 
the arterial circulation. In what portion of its course 
the principal artery was obstructed could hardly be 
ascertained after a lapse of fourteen days, inasmuch as 
collateral circulation had probably been set up. It 
appeared, however, certain that the occluding clot could 
not be in the ophthalmic artery, inasmuch as the cho- 
roidal circulation was not only unimpaired, but seemed 
even more vivid than in the other eye, to judge from 
the existing increase of intra-ocular pressure. As has 
been stated, a spindle-shaped swelling could be made 
out in one artery, on either side of which the vessel was 
extremely narrowed. The whole region gave the 
impression that we had here to do with a small embo- 
lus, which had obstructed a single branch of the central 
artery. This observation agrees entirely with that of 
Cohnheim, according to which the channel of the vessel 
is more or less dilated at the point of obstruction, but ap- 
pears decidedly contracted both in front of and behind it* 
The second and principal embolus must, of course, be 
situated in the trunk of the artcria centralis retince, at 
what point will be discussed further on. The source 
of the embolus was the next question. The most 
thorough examination of the heart and the large vessels 
revealed nothing in the least abnormal to either percus- 
sion or auscultation ; the radial arteries, however, espe- 
cially the left, showed hard atheromatous deposits in the 
middle coat, yielding to the finger the familiar sensation 
of a bird's trachea. Inasmuch as an atheromatous con- 
dition of the cerebral arteries is frequently present with- 
* Loc. cit., p. ii. 50 
J. Samelsohn: 
out any manifestation of atheroma in the remaining 
arteries of the body, while conversely atheroma of the 
arteries of the body seldom fails to implicate those of 
the brain, it became necessary to assume some process 
within the internal carotid or ophthalmic arteries, from 
which diseased vascular remon the current of the circu- 
o 
lation swept particles of tissue or thrombic clots into 
the central artery and one of its branches.* The in- 
ducement to believe in some such disease of the cere- 
bral vessels and the consequent derangement of nutri- 
tion of the organ itself became all the greater when it 
was considered that the woman had previously been both 
cheerful and lively, but of late had grown melancholy, 
lachrymose, and had come to be haunted by impressions 
of impending misfortune ; the veins of the face, more- 
over, exhibited unmistakable symptoms of stagnation of 
the circulation. Urine normal. I venture only to hint 
at the possibility of a connection between the micropsia 
of the right eye and the above-described derangement 
of nutrition.f The following points bore on the ques- 
tion of therapeutics : 
1. The mobility of the pupil when exposed to light, 
and the perception of light, slight though it was, in a 
limited portion of the visual field ; 
2. Phosphenes responding to pressure ; 
3. Absence of any striking alteration of tissue in the 
retina; 
4. Absence of any cardiac disease. 
* Cf. Steffan, loc. cit., p. 39. Liebreich, Deutsche Klinik, 1861, No. 50, p. 476. 
f Cf. Panum. The apparent Sice of Visible Objects. Graefe's Archiv, Bd. V., 1, 
p. 16. Embolism of the Central Artery of the Retina. 
51 
The slight but still uniform and equal fulness of the 
arteries and veins giving good grounds for belief that 
the collateral circulation proceeded from the ciliary vas- 
cular plexus, the first indication seemed to be, by stimu- 
lating this, to cause an afflux of blood towards the retina 
that should not only prove a source of nutrition to its 
tissue, but also enable it to resume its functions. For 
thus must we theorize with regard to the apparently 
singular fact that a failure of nutritive supply may not 
cause the destruction of a tissue, while leading to a 
limitation or entire suspension of its functions ; the col- 
lateral circulation following directly on the obstruction 
being sufficient to prevent the necrosis of retinal tissue, 
but unequal to the task of maintaining an exercise of 
functions that are necessarily accompanied by a large 
consumption of material; a view of the case amply jus- 
tified by analogy in other organs. This view, too, har- 
monizes very well with the fact of the good preserva- 
tion of the phosphenes. For inasmuch as the larger 
retinal arteries ramify in the inner, conducting, layers of 
the retina, irritation of which originates the phosphenes, 
these layers, though their vessels be but partially filled, 
must retain a certain limited activity beyond that 
enjoyed by the external, perceptive, retinal layers, 
which are permeated only by the finer subdivisions of 
the central artery, and must hence remain more empty 
when the circulation is impeded.* 
* Cf. Steffan, 1. c., p. 62, whose view of the exclusive supply of the external reti- 
nal layers by the chorio-capillaris is hardly tenable. I would simply refer, in this 
connection, to the preservation of the functions of a retina overlying choroidal rup- 
tures, etc.; Knapp, Archives of Ophthalmology and Otology, I., 1., p. 169. 52 
J. Samelsohn : 
The question, of course, arose whether a stimulation 
of the retinal circulation, provided we could bring this 
about, might not drive the embolus still deeper into 
the central artery, and thus gravely compromise the col- 
lateral circulation, so recently established. This doubt, 
upon which the treatment of Schneller's* single success- 
ful case was based, appeared to have no bearing on the 
present one. In the first place, the embolus having 
remained fourteen days in one place, which it entirely 
filled, could hardly be assumed to be sufficiently mov- 
able to yield before the dash of the blood; in the 
second place, we had a right to argue that the current 
would follow, by preference, the already open channels 
of the collateral circulation, a thing proved by experi- 
ment, inasmuch as clots generally extend to the next 
higher anastomosis. 
Among the means of bringing about an increase of 
force in the circulation towards the retina, iridectomy 
occupied the first rank, an additional inducement to its 
performance being the indubitable increase of intra- 
ocular pressure. This increase of intra-ocular pressure 
is a phenomenon both significant and interesting ; signi- 
ficant in regard to its results, which impeded the rapid 
accomplishment of a collateral circulation ; interesting 
with reference to its development, which allows us an in- 
sight into the peculiar derangements of circulation that 
accompany retinal embolism. These derangements of 
circulation in an eyeball closed on all sides, and pro- 
vided with two nearly independent vascular systems, 
* Graefe's Archiv, VIII., i, p. 274. Embolism of the Central Artery of the Retina. 
53 
must run a course very different to that observed in the 
tongue of the frog, the object studied by Cohnheim. 
In this latter case the single requisite for the forma- 
tion of a collateral circulation is the presence of anasto- 
moses, and the tissue interposes no obstacle to the re- 
establishment of a vascular current, while in the former 
the greater or less rigidity of the sclero-corneal cap- 
sule, the tension of which is maintained by the vitreous, 
offers a very appreciable resistance. The normal retinal 
circulation is an indubitable adjunct to the amount of 
the intra-ocular pressure, through the quantity of blood 
contained in the retinal vessels; still it is now beyond 
disputation that the choroid and ciliary body are the 
real source of the fluids that create the intra-ocular 
pressure. When now an embolic closure eliminates the 
retinal circulation, how is the intra-ocular pressure af- 
fected ? At the very first it will undoubtedly decrease 
in direct proportion to the amount of blood circulating 
in the retina; this decrease, however, is partially neu- 
tralized, and finally reduced to a minimum by the elastic 
contraction of the envelope of the globe. The situa- 
tion, however, almost immediately changes. The ob- 
struction of the central artery drives the blood into one 
or several of the preceding lateral branches of the oph- 
thalmic, and causes it to flow with increased rapidity into 
these, i.e., the ciliary arteries ; " with the same increased 
rapidity the blood traverses the capillaries supplied by 
the said lateral branches, and runs all the more quickly 
into the veins that carry it off. This acceleration of 
the circulation in these arteries, capillaries, and veins 
remains for a longer or shorter time at the same height, 54 
J. Samelsohn: 
without causing a rupture and hemorrhage, until finally 
a gradual and equable distribution of the superfluous 
current is made over several of the preceding neigh- 
boring branches, and an equilibrium thus established." * 
I have almost literally transcribed this passage from 
Cohnheim's article, because this observation, based on 
experiment, seems to me to furnish the key to a proper 
conception of the mechanical conditions that ensue on 
vascular obstruction due to embolism. At a later period 
we shall more clearly perceive the neglect that has been 
bestowed on, and the faulty conclusions that have been 
derived from, this state of things. If these experimental 
results be applied to the present case, it will be seen 
that the circulation will be affected as follows: The 
blood will flow with increased rapidity through the 
ciliary arteries to the chorio-capillaris and ciliary veins ; 
the process of filtration is thus hastened and the intra- 
ocular pressure increased; this temporary increase of 
the inner pressure of the eye hinders again the quick 
completion of the collateral junction in the region of the 
optic papilla, and the blood hence rushes with a con- 
stantly growing rapidity into the posteriorly situated 
ciliary arteries. As the intra-ocular pressure increases, 
the activity of the increased rapidity is converted into 
an increased lateral pressure, and the filtration pressure 
of the chorio-capillaris thus increased, so that as a final 
result of the dilemma we note an increase in the intra- 
ocular pressure and an impeded current in the direction 
of the collateral optic vessels, and this in spite of the 
* Cohnheim, 1. c., p. 9. Embolism of the Central Artery of the Retina. 
55 
vascular distribution at the extremity of the optic nerve 
that seems so favorable to the quick development of a 
collateral circulation. 
Guided by this reasoning, I decided at once to per- 
form iridectomy, the influence of which to diminish 
pressure in a similar case had already been tested by v. 
Graefe.* On the very next day I made a broad colo- 
boma upwards, and took pains to let the aqueous humor 
escape somewhat rapidly. The day following I could 
not refrain from a cautious examination of the vision and 
the fundus, the absence of all reaction rendering this 
apparently devoid of danger. There could be no doubt 
of an increased perception of light, extending over a 
large portion of the visual field ; it was, however, in no 
degree qualitative. Ophthalmoscopic examination re- 
vealed a considerable alteration in the state of the ves- 
sels ; the arteries were much fuller, and distinguishable 
from the veins by their color as well as by a certain 
reflex, this distinction being most marked in the arte- 
rial branch containing the swelling that has been charac- 
terized as an embolus. The central contraction in 
calibre of the vessel had now disappeared, and with it 
the spindle-shaped enlargement, but it was, as before, 
impossible to trace the vessel at its peripheric continua- 
tion beyond the embolus. The latter, however, had not 
changed its position. The result of the following and 
more comprehensive examination, which was made 
three days after the operation, was the astounding fact 
that the patient could count fingers with tolerable cor- 
* Cf. Graefe's Archiv, V. I, p. 151. Knapp, Ueber Verstopfung der Blutge* 
fiisse des Auges, Graefe's Archiv, XIV., 1, p. 219. 56 
J. Samelsohn: 
rectness, not, it is true, centrally, but with a portion of 
the retina closely bordering on the centre ; only below 
and inwards no trace of a perception of light had re- 
turned, corresponding entirely to the spindle-shaped 
swelling which lay in the inverted image, below and in- 
wards. Ophthalmoscopic appearances the same as two 
days before. During the next few days the improve- 
ment somewhat progressed; large objects like a watch, 
key, knife, etc., being made out, and the power of vision 
gradually approached the centre. A change, too, in the 
ophthalmoscopic appearance of the macula lutea could 
now be observed. The blood-red color gradually dis- 
appeared from without inwards (inverted image), and 
gave way to a brownish yellow, without, however, the 
development of any opacity at this point. I must ad- 
vert here to one very strange symptom. While the 
patient, in a darkened room, had an accurate perception 
of fingers and other objects gently illuminated by a gas- 
jet at her side, except over that portion of the visual 
field that has been already repeatedly alluded to, she 
was yet unable to recognize or state the position of the 
full jet of gas when carried directly before her eyes. 
A curious analogy exists between this and cutaneous 
analgesia, and has been already several times advert- 
ed to in cases of amblyopia following a large loss of 
blood.* It seems to me more an evasion than an ex- 
planation of this phenomenon, to say that the retina, 
long disabled functionally, responds to a slight, but is 
exhausted by a strong, stimulus, and I simply here note 
* Vikentscher, Graefe's Arcliiv, VIII., i, p. 213. Colsman, Klinische MonatsbL, 
VII., p. 13. Embolism of the Central Artery of the Retina. 
57 
the fact. Not till ten days after the operation did this 
symptom disappear and the patient accurately localize 
the largest flame. 
I expected now that the improvement in the power of 
vision would steadily progress. My hope was, however, 
disappointed, and soon gave way to the fear that what 
had already been gained might yet be lost. In this 
apprehension I was by no means guided by the per- 
ception of light, which persisted over the whole surface 
described, but by the ophthalmoscopic appearance of 
the retinal vessels; for these began again to exhibit 
a diminished calibre, especially the branch with the em- 
bolus, which latter clearly displayed again a spindle- 
shaped swelling, on either side of which the vessel was 
contracted, just as before the operation. It was clear 
that the diminution of intra-ocular pressure, due to the 
operation, had begun to lose ground, and that the pro- 
cess of cicatrization was offering a fresh obstacle to the 
collateral circulation that had been excited. 
Under these circumstances the patient was dismissed 
from the hospital, but has remained under surveillance 
up to the present time. The ophthalmoscope reveals 
now the last-described state of things, the vessels being 
moderately contracted, the spindle-shaped swelling 
present, the veins less attenuated at their point of emer- 
gence, and the macula lutea yellowish brown. The 
white discoloration of the papilla has not increased, and 
neither has any alteration in the visual power of the 
left eye taken place since the examination last described. 
Nor is the right eye at all changed, and, according to 
the patient's account, the micropsia remains the same. 58 
J. Samelsohn : 
I cannot, at present, find any reason for this either in 
the accommodation or the retina. 
On reviewing now the single elements which went to 
make up the diagnosis of our case, we are struck first 
of all with the absence of that loss of transparency of 
the tissue which, with hardly an exception, has charac- 
terized every case of embolism of the central artery that 
has hitherto been described. The objection might in- 
deed hold that this was present during the days that first 
elapsed after the formation of the embolus, and had 
already disappeared without leaving a trace behind, 
when I made my first observation, fourteen days after 
the advent of blindness. A glance at the best known 
of the hitherto published cases will most quickly inform 
us with reference to the admissibility of such a theory. 
The table opposite shows that the commencement of 
opacity of the tissue is ordinarily noted during the days 
that immediately succeed the embolic obstruction, and 
that, while the opacity in many cases takes more than 
fourteen days to disappear, shorter periods are not un- 
common. Under these circumstances we are not called 
upon to decide on the absence of opacity in our case, and 
are at liberty to rank it with Schneller's, which he 
observed the twelfth day after blindness occurred, and 
noted no opacity of the tissue whatever. These two 
observations, however, open the discussion as to 
whether the early or late occurrence of opacity of the 
tissues is a necessary consequence of the embolic oc- 
clusion of the central artery. Embolism of the Central Artery of the Retina. 
59 
Table i. 
No. 
Name of 
observer. 
Situation and 
extent of the 
opacity. 
Day it ap- 
peared after 
the attack. 
Day it 
disappeared. 
Where recorded. 
I 
v. Graefe. 
Macula lutea and 
14 
30 
Graefe's Archiv, 
a portion of the 
V., i, pp. 149- 
papilla. 
152. 
2 
Blessig. 
Macula lutea, pa- 
Some 
Thirty 
Graefe's Archiv, 
pilla and retina 
hours. 
days later 
V. III., 1, p. 
below the pa- 
pilla. 
still present. 
219. 
3 
Schneller. 
Vicinity of papilla 
- - - - 
.... 
Graefe's Archiv, 
slightly veiled. 
VIII., 1, p. 
272.* 
4 
Liebreich. 
Macula lutea. 
.... 
.... 
Graefe's Archrv, 
V., 2, p. 263.} 
Deutsche Klinik, 
5 
Liebreich. 
In each of six cases 
i-6 
6-? 
opacity of the 
macula and the 
papilla. 
1861, No. 50, p. 
476. 
Atlas ot Ophthal- 
moscopy, Pl. 8, 
Fig- 4- t 
6 
Steffan. 
Macula and pa- 
4 
40 
pilla. 
Graefe's Archiv, 
XII., 1, pp. 37- 
7 
Saetnisch. 
Lower portion of 
2 
5 
38- 
retina. 
Klin. Monatsbl., 
1866, p. 34. 
8 
Schirmer. 
Retina and pa- 
2 
30 
Klin. Mon., VI., 
pilla, no opacity 
around macula. 
41. 
9 
Knapp. 
i f Macula and 
5 
19 
Graefe's Archiv, 
The last of 
2 4 papilla. 
I 
. • • • 
XIV., 1, pp. 
the 5 cases 
3 ( 
2 
20 
210-220. 
can hardly 
be includ- 
ed. 
4 No opacity. 
...» 
IO 
Knapp. 
Retina, macula a- 
Observed 
3 weeks after 
Archives of Oph- 
round the infarc- 
the attack of blindness. 
thal. and Otol. 
tus. 
I-, 1, P- 64. 
* Schneller's case, distinguished beyond nearly all others by a considerable restora- 
tion of vision, came under his observation the twelfth day after the advent of the 
blindness. 
f The case is described with much brevity, and hence allows no appreciation of 
its circumstances. 
| The opacity constantly occurred, sometimes early, sometimes late, disappear- 
ing in like manner. Liebreich gives no further particulars. 60 
y. Samelsohn : 
A proper estimation of the derangements in the 
tissues that ensue on the occlusion of an artery is based 
wholly and entirely on " whether behind the coagulum, 
between it and the dependent capillary tract, there is 
given off an arterial branch that directly inosculates 
with any other artery, or whether such an anastomosis 
is wanting." * If the latter be the case, that is, if the 
occluded artery be a terminal one, its embolic occlusion 
may give rise to a double series of derangements, 
entirely independent of each other. "First, necrosis, 
the natural consequence of the cessation of circulation 
in an animal organ; secondly, engorgement, due to the 
reversed action of the current of the neighboring vein, 
a current impeded in the retina by no venous valves. 
The combination of both chains of deranged symptoms 
is the infarctus." f 
This being the fundamental law, it is a source of sur- 
prise that the embolic infarctus of the retina should 
have been accurately noted in but a single case, while, 
on the other hand, it adds considerable force to the 
observation that this infarctus took place in connec- 
tion with an embolism of a branch of the central artery, 
a branch of whose significance as a terminal artery 
there can be, according to Cohnheim's construction, no 
doubt. On reading the critical remarks appended by 
Knapp to his case, we gladly admit that he fell but little 
short of a solution of the whole process, the final the- 
oretical verdict being reached by Cohnheim's experi- 
mental observation. 
* Cohriheim, 1. c„, p. i6. f Cohnheim, 1. c., p. 61. Embolism of the Central Artery of the Retina. 
61 
To bring about an opacity of the tissue, which must 
be regarded as an optical evidence of necrosis, it is 
essentially necessary that the artery supplying the tissue 
concerned should be terminal, the occluded vascular 
region being, in any other event, simply eliminated from 
the circulation. If this be the stand-point from which 
we proceed in our consideration of the retinal circula- 
tion, we find at once that the authorities are at vari- 
ance. While Cohnheim denominates the central retinal 
artery, at its point of departure from the papilla, dis- 
tinctly terminal, referring to a point beyond the slight 
connections between it and the ciliary arteries that here 
traverse the optic nerve,* Leber says, " The small 
arteries which proceed from the plexus surrounding the 
optic nerve go in part inwards, to that portion of the 
nerve that lies before the lamina cribrosa, in part run 
more posteriorly into its trunk. Their connections with 
the branches of the central artery seem generally pretty 
minute. Very minute branches are continued also into 
the retina in the immediate vicinity of the papilla. 
It is therefore an established fact that the ciliary vessels 
contribute to the nutrition of the papilla and the adjoin- 
ing portions of the optic nerve and the retina. Consider- 
ing this appreciable vascular connection at the point of 
entrance of the optic nerve, it is astonishing that, after 
a complete embolism of the central retinal artery, no 
more considerable collateral circulation should be estab- 
lished." f 
In accordance with these investigations of Leber, 
* Cohnheim, 1. c., p. 72. f Graefe's Archiv, XI., 1, pp. 6 and 7. 62 
J. Samelsohn: 
and as long as they are not controverted, must we 
base our faith, and hence allow the possibility of an 
undoubtedly imperfect supply of the retina from these 
ciliary connections, afte.. an embolic occlusion of the 
central artery on the further side of the minute connec- 
tions with the ciliary arteries, and regard only the 
branches of the central artery as terminal arteries in 
the full sense of Cohnheim's views. At all events, these 
direct connections between the ciliary arteries and the 
retina are so slight as to seriously compromise the nu- 
trition of the latter when supplied from this sole source ; 
and when we note the considerable amount of opacity 
that accompanies the closure of a branch of the central 
artery, the assumption will not seem forced that appreci- 
able necrotic opacities of the retina, and consequent 
incurable destruction of its functional capacity, must re- 
sult from an occlusion of the central artery at a point 
beyond the giving off of the ciliary connections. It is 
both theoretically probable and practically established 
that, in a necrosis of this kind, the primary impairment 
will be in the region of the macula lutea, a spot which 
in the normal state is particularly devoid of vessels. 
Should the necrosis recede as rapidly as it advanced, 
it is to be assumed that the embolus is situated at a 
point particularly favorable to the development of the 
ciliary collateral current, which collateral current may, 
as has already been indicated, be sufficient to arrest the 
necrosis and remedy the opacities that have already 
been induced, without being sufficiently ample to bring 
about a resumption of function. The period of occur- 
rence of necrotic opacity of the tissue (aside from Embolism of the Central Artery of the Retina. 
63 
cific, infected embolisms) may thus become a valuable 
means of diagnosis for us in determining the locality of 
the vascular obstruction, and the clearing up of the 
opacity as accurate an index of the time and extent of 
the collateral connection. 
A second point, about which authors exhibit many 
discrepancies, and which I am apparently allowed by 
the experiments of Cohnheim to view under a single 
aspect, is the form and contents of the occluded ves- 
sels. The following table (p. 64) bears thereupon. 
This table exhibits wide variations in the abnormal 
state of the vessels, both as regards contents and shape. 
Although, in the majority of cases noted, the arteries 
appear appreciably narrowed, and exhibit from the cen- 
tre towards the periphery a diminution in calibre, there 
are yet two cases that show a directly opposite state of 
things (Cases 2 and 7), the arteries being decidedly 
fuller at their peripheric distributions than at their cen- 
tre. These two cases, that seem decidedly without the 
pale of typical embolism of the retina, are capable, on 
closer examination, not only of entire explanation, but 
furnish at the same time a clue to the occurrence of ex- 
travasations that we have to allude to farther on. For 
on comparing Case No. 2 with Figure No. 7 in Cohn- 
heim's article,* we see that the whole affair amounts to 
a replenishing of the occluded artery by means of an 
arterial anastomosis from the ciliary plexus of the optic 
nerve, an explanation harmonizing fully with Blessig's 
remark that the greater fulness of the very contracted 
* L. c., p. 16, and plate. 64 
J. Samelsohn : 
Table 2. 
No. 
Name of au- 
thor. 
Arteries. 
Veins. 
I 
v. Graefe. 
Extremely narrow lines. 
Thin ; their unequal fulness in- 
creasing towards the equator. 
2 
Blessig. 
Small red lines; they contain a 
certain amount of blood some 
distance from the papilla; in 
most of them this amount of 
blood and their diameter dimin- 
ish as the papilla is approached. 
Narrowed and best filled to- 
wards the periphery ; une- 
qual fulness throughout their 
whole course. 
3 
Schneller. 
Thin, red streaks confined within 
two white lines. 
Narrow, growing thicker to- 
wards the papilla. 
4 
Liebreich. 
Wholly void of blood. 
Thin, becoming thick in the di- 
rection of the periphery. 
5 
Liebreich. 
Thin. 
Thin, tapering towards the 
point of emergence. 
6 
Steffan. 
Thin. 
Thin, tapering towards the 
point of emergence. 
7 
Saemisch. 
Thin and quite white, at one place 
some blood is retained ; above 
the white coloration an enlarge- 
ment. 
On the tenth day after the 
advent of blindness some blood 
could be proved to be contained 
in the peripheric portions of the 
occluded arterial branch ; the 
current advancing towards the 
centre, but still showing an in- 
terruption. 
The corresponding vein is some- 
what enlarged, especially to- 
wards the papilla. 
8 
Schirmer. 
Very thin, the column of blood be- 
ing nowhere interrupted. 
On the papilla very thin, at 
some distance from it abnor- 
mally large, tortuous, exhibit- 
ing a type of stagnation. 
9 
Knapp. 
1. Very thin and threadlike, quite 
rapidly decreasing in diameter in 
the direction of the periphery. 
2. Threadlike, single in contour, 
not to be traced far beyond the 
papilla. 
3. Very thin. 
1. On the papilla most narrow 
and very dark; thicker to- 
wards the periphery. 
2. Very thin, larger towards 
the equator. Fulness equal. 
3. Well filled, with shifting in- 
terruptions. 
4. Thin, with a slight enlargement 
on the papilla. 
4. Rather thinner than normal. 
IO 
Knapp. 
Thin, like a fine red thread, that 
becomes suddenly transformed 
again into a ribbon with a double 
contour. 
The corresponding vein enlarg- 
ed and tortuous. Embolism of the Central Artery of the Retina. 
65 
arteries began immediately beyond their passage over 
the edge of the papilla, that is, at the point where, 
according to Leber, branches of the ciliary arteries 
directly enter the retina. There results hence the ex- 
treme probability that the embolus had been carried 
down to a great depth in the central artery. 
Case No. 7 possesses an entirely different signifi- 
cance. The phenomenon of decided arterial engorge- 
ment at the periphery is here presented, not at the com- 
mencement of the blindness, but as late as the tenth 
day. It is probably an instance of a retrogressive 
movement from the neighboring vein. " It begins at 
the point of union of the passive with the flowing vein, 
the latter emptying the greater portion of its contents 
in the normal direction of the heart, but passing, too, a 
certain quantity into the immovable venous branch, in a 
directly contrary direction.* In the case referred to, the 
vein corresponding to the branch containing the embo- 
lus was somewhat swollen, especially in the direction of 
the point of emergence from the papilla ; the fulness of 
the occluded arterial branch began at the periphery and 
advanced gradually forward in the direction of the cen- 
tral extremity, without, however, causing the interrup- 
tion of fulness to disappear. A similar explanation 
may be offered regarding the phenomenon of unequal 
fulness of the veins, with intermitting motion of their 
contents, observed in some cases (1, 2, 9, 3), inasmuch 
as Cohnheim has observed and described a similar in- 
termitting movement, a going and coming, first occur- 
* Cohnheim, 1. c., p. 18. Fig. 6. 66 
J. Samelsohn: 
ring when the fulness of the veins has attained a certain 
height by means of the retrogressive current.* 
We find, moreover, laid down in the table that the 
arteries at times appear thin, or like a fine red streak, 
or, again, like a fine red line bounded on either side by 
two fine white lines, or finally, like entirely white bands. 
As is well known, this utterly varying description on 
the part of single observers has led Stellwag von Carion 
in especial to express the doubt as to whether we have 
not, in the observations in question, to do rather with a 
perivascular inflammation than with an embolism. But 
the observations of Cohnheim allow us even here to 
array all the types described under the head of a gen- 
eral and final cause. A glance at his figures, 4, 5, 6 and 
7, gives us the explanatory clue to the possibilities de- 
scribed. The explanatory text teaches us that the dif- 
ferent types are simply due to the rapidity with which 
the occlusion takes place; according as the embolus 
suddenly obstructs the whole trunk of the vessel, or 
gradually increases from partial to total, so do we remark 
on either side of it now a tranquil column of red blood, 
again a tranquil red column behind, and a colorless col- 
umn of plasma before the obstruction, and yet again a 
pale, colorless vascular trunk as a consequence of the 
embolism. And that a process of embolism may occur 
that gradually leads to an entire closure of the canal of 
the vessel, we find sufficient proof in the records of 
cases that treat of the obscurations preceding the attack 
of actual blindness. 
* Cohnheim, 1. c., p. 19. Embolism of the Central Artery of the Retina. 
67 
Table 3. 
No. 
Observer. 
Number and form of 
extravasations. 
Position of 
extravasations. 
Day of 
occurrence 
after the 
attack. 
Form of red spot at the 
macula lutea. 
I 
v. Graefe. 
None. 
None. 
.... 
Cherry-red spot in the 
immediate vicinity of 
the foramen centrale. 
2 
Blessig. 
Two ecchymoses, 
the one on, the 
other near, a ret- 
inal vein. 
Around the 
macula lu- 
tea. 
IO 
A red spot in the fora- 
men centrale. 
3 
Schneller. 
None. 
None. 
None. 
4 
Liebreich. 
Small ecchymoses 
on the veins. 
Around the 
macula lu- 
tea. 
5 
Liebreich. 
Ecchymoses in all 
six cases. 
Around the 
macula and 
papilla. 
In all six cases without 
any detailed informa- 
tion, except that they 
were situated in the 
opacity of the macu- 
la. 
6 
Steffan. 
Two small extra- 
vasations. 
At the edge of 
the papilla, 
the one be- 
low, the oth- 
er outwards 
9 
In the centre of the 
milk-white opacity. 
7 
Saemisch. 
8 
Schirmer. 
At the macula a red 
spot, easily distin- 
guishable from an ex- 
travasation. 
9 
Knapp. 
r. Numerous, stri- 
ped and spotted. 
2. .... 
3. One hemor- 
rhage. 
4. 
In the opaque 
retina, 
around the 
macula, ex- 
tending to 
the papilla. 
Close in the 
vicinity of 
the upper 
edge of the 
papilla. 
5 
2 
A cherry-red place 
around the yellow 
spot. 
A small dark-red spot 
on the macula. 
We have yet to consider a symptom by no means 
constant, name'y, that of extravasation, with which we 68 
J. Samelsohn: 
will connect a discussion of the much-argued question 
as to the red coloration of the favea centralis. Let us 
then seek to derive from a table some information as to 
the frequency of extravasation. (See page 67.) 
With these cases must be ranked Knapp's observa- 
tion of the infarctus, made three weeks after the advent 
of blindness, and in which the numerous hemorrhages 
were situated around small venous branches. The red 
spot at the macula is recognizable, it is true, on the col- 
ored plate, still is markedly different from other descrip- 
tions and representations. Of its significance as an 
ecchymosis there is in this case no doubt. 
In the above 28 cases the table exhibits to us 12 
instances of ecchymosis, which vary not inconsiderably 
in number and in size. Their site is generally about 
the macula lutea, sometimes in the neighborhood of the 
papilla. On comparing the last table with table No. 1, 
it becomes evident that, in all cases in which ecchy- 
moses are noted, their sites exhibit proof of necrotic 
changes of tissue. In 3 cases the hemorrhage is 
expressly described as proceeding from the retinal 
veins. As regards, finally, the period of occurrence, we 
unfortunately find no details given in the most cases ; 
according, however, to the positive observations made 
in some cases, it happens generally several days after 
the embolic obstruction. In but a single case (Knapp, 
No. 3) do we find allusion to an extravasation close to 
the papilla the day succeeding the sudden advent of 
blindness. 
On collating now these several data and comparing 
them with the results of the experiments of Cohnheim, Embolism of the Central Artery of the Retina. 
69 
I think we shall find no difficulty in passing judgment 
on them from a single point of view. It has already 
been stated that no theory of an arterial hemorrhage in 
consequence of the collateral fluxion, succeeding the 
occlusion of the principal branch, can obtain, all the less, 
indeed, because this collateral fluxion would have to be 
greatest after the occlusion, and diminish or entirely 
disappear in proportion as time went on.* The case 
must be one, therefore, of extravasation from the veins 
or capillaries, described by Cohnheim as the result of 
venous accumulation, combined with necrosis of the tis- 
sue or vascular walls, and to be regarded as paving the 
way to an infarctus. A properly typical picture of this 
infarctus has been furnished us by Knapp, and it is cer- 
tainly to be regarded as a triumph of ophthalmoscopic 
observation that the embolic infarctus should be, in this 
case, pointed out to be a venous extravasation, in entire 
opposition to the views previously obtaining. This 
observation has in itself fulfilled the second portion 
of the hope expressed by Virchow, and cited in the 
introduction to this article, and the experimental in- 
vestigations of Cohnheim have rendered possible the 
pathogenetic elucidation of its mechanical details. 
Blessig, too, was on the scent of the right solution. 
"The extravasations occurred subsequently to the dis- 
solution of the retinal elements. This later appearance, 
as well as the circumstance that hemorrhages into the 
parenchyma took place only on those portions of the 
retina that were opaque, and hence liable to be more 
* Cohnheim, 1. c., p. 88. 70 
J. Samelsohn : 
thoroughly and quickly affected by the derangement of 
nutrition, go to prove that the dissolution of the tissue 
must have been a primary, and the hemorrhage into the 
degenerated and softened retinal tissue a secondary, 
symptom. I lay great stress upon this circumstance, 
because the occurrence of hemorrhagic processes in the 
vicinity of arteries occluded by embolism is generally 
explained on the theory that collateral fluxion causes 
the blood to collect in the region of the occluded arte- 
ries, and ultimately brings about a rupture of the ves- 
sels." * Although this theory nearly approaches the 
one of Cohnheim adopted by us, we still see from the 
sentence immediately following this explanation how 
slight a conception Blessig had of the mechanical con- 
comitants of extravasation, and how this depended on 
the lack of experimental microscopical observations. 
For he goes on to say : " It is perhaps a consequence 
of the sparse collateral communications in the vascular 
tract of the central artery of the retina, that more pro- 
nounced and extensive parenchymatous hemorrhages 
have not been noted in embolism of the same." The 
picture drawn by Knapp of retinal infarctus may be con- 
sidered typical according to the views of Cohnheim, 
and in the critical analysis of the case there is nothing 
wanting except the retrogressive venous current from 
the neighboring vein, a knowledge of which indeed 
could hardly be theoretically attained. If, on the other 
hand, it is demanded why extravasations are not met 
with in all cases in which necrosis of the retinal tissue 
* Graefe's Arcliiv, VIII., r, p. 224. Embolism of the Central Artery of the Retina. 
71 
is found, I would refer to the frequently cited article of 
Cohnheim,* which contains an exhaustive discussion of 
the circumstances in question. 
We have still to discuss the inquiry as to whether the 
red spot at the macula lutea, that has grown to be an 
almost pathognomonic indication of embolism of the 
central artery of the retina, is to be interpreted as a 
phenomenon of contrast or a hemorrhage. We find it 
noted thirteen times in the eighteen cases of the table, 
and are justified in distinguishing between it and the 
infarctus, an indubitable hemorrhage into the retina. 
Among these remaining twelve cases we find the red 
spot associated eleven times with a white discoloration 
of the macula lutea. The only time that the red spot 
existed, without opacity of the macula lutea, we find 
expressly stated that " a reddened place is met with on 
the macula lutea, between which and an extravasation 
there is a distinct difference." (Case 8, Schirmer.) 
In another of these cases (9, Knapp's third case), an 
ecchymosis at the upper edge of the papilla is described, 
and then a small, dark-red spot on the macula lutea 
alluded to ; a similar coincidence occurs, moreover, in 
Blessig's case: one would think that the question of 
likeness or dissimilarity would be easily decided, owing 
to such an immediate juxtaposition of two red spots. 
In considering Steffan's discussion of the present ques- 
tion,! it is presently discovered that this is based on a 
false mechanical principle, that of arterial collateral flux- 
ion, and, with its result, the formation of extravasation 
* L. c., pp. 85-88 f Graefe's Archiv, XII., 1, pp. 39-47. 72 
J. Samelsohn : 
in the choroid, must be held erroneous ; hemorrhages 
from arterial fluxion having been proved by Cohnheim 
untenable. Looking now at the table with a view of 
ascertaining the form of development of this red spot 
in the several cases, we find the description to present 
no inconsiderable variations. At one time there is a 
cherry-red spot in the immediate vicinity of the foramen 
centrale, at another situated on the foramen centrale 
itself; sometimes it is described as on the macula, and 
sometimes indeed as around it. In the case I myself 
observed I found it red, with a granular surface, indis- 
tinct boundaries, entirely unlike an extravasation, with 
no parallax to be made out between it and the neigh- 
boring retinal veins.* The red coloration was most 
intensive in the middle, corresponding to the fovea cen- 
tralis, and passed through a succession of less brilliant 
shades till it merged in the normal fundus. Its disap- 
pearance was gradual and equal on all sides, the red 
color slowly melting into the ordinary yellow-brown. 
The impression made on me by the red patch, I have 
already described as entirely dissimilar to that produced 
by an extravasation, and I am very well able to con- 
ceive how, when a whitish coloration occupies all of the 
yellow spot but the fovea centralis, the intensely red 
centre must appear as .a hemorrhage. Inasmuch now 
as I find no anatomical foundation for a venous hemor- 
rhage in the region, and especially the centre of the 
macula lutea; inasmuch, moreover, as no veins quit the 
*It seems almost incredible that the binocular ophthalmoscope should be neg- 
lected, as a means of diagnosis, in such cases, and a " parallax " gravely alluded to 
in determining differences of level.-Translator. Embolism of the Central Artery of the Retina. 
73 
choroid at the portion posterior to the macula hitea; 
inasmuch, however, as the most numerous and vigorous 
twigs of the short posterior ciliary arteries enter the 
choroid exactly at the posterior pole,* it is easily seen 
that the collateral fluxion succeeding the embolism may 
attract especial notice by its deep-red color, exactly at 
the point where the vessels are still closely packed 
together, since this fluxion consists in an acceleration 
of the current of blood through arteries dilated under 
an increased pressure, without any extravasation 
through the arterial walls being yet brought about. In- 
asmuch now as the middle of the yellow spot is color- 
less, nearly wholly transparent, and at the same time 
the thinnest portion of the retina,f the normal appear- 
ance of the fovea centralis is that of a dark-red spot; 
if now, on the other hand, an increased redness of the 
choroidal polar region occurs, the color of the fovea 
centralis must naturally increase. When, as in my 
case, this red color embraces the whole macula lutea, 
in gradually decreasing intensity indeed, and without 
sharply-defined boundaries, I find in exactly this cir- 
cumstance an increased support of the theory advanced : 
for in the first place the thickness of the remainder of 
the macula lutea is more considerable than that of the 
fovea centralis, and in the second place the boundaries 
of the yellow spot are never as sharply defined in old 
* Leber. Investigations concerning the course and connections of the vessels in 
the human eye. Graefe's Archiv, XI., I, p. 14. 
I H. Muller. Anatomic-physiological investigations concerning the retina of men 
and vertebrates. Zeitschrift fur Wissensch. Zoolog., VIII., p. 1-122. Gesain- 
melte Abhandlungen, p. 30J. 74 
J. Samclsohn. 
people as in children ; from the last circumstance it 
necessarily results that the superjacent retinal pigment 
must cause the circumscribed hyperaemia of the choroid 
to appear somewhat diffuse. This explanation is fav- 
ored, too, by the gradual and equable disappearance of 
the red color, without the occurrence of any perceptible 
change of tissue. 
Cologne, November, 1872.