C. H. Usher 
47 
B. The Eye of the Adult Human Albino. 
In literature there are few records of a microscopical examination of a human 
albino eye. In all, these relate to two pieces of iris, removed during operations 
for the extraction of senile cataract(6), and to the eyeballs of six other cases* 
(Manz, Nettleship, Fritsch, Adler and Mcintosh, Coats, Elschnig). Of the two 
pieces of iris, one (Nettleship, Fig. F) contained no pigment, the other (Usher) 
had an abnormally small quantity of pigment in the two posterior epithelial 
layers and not any in the stroma (Fig. D). Of the six albinos where the whole 
eyeball was obtained, live were adults, and the sixth was an infant of ten weeks. 
All of the eyes from four of the adults contained some pigment, in the fifth case 
Fritsch (7) makes no mention of either the presence or absence of pigment in the 
eye. In the case of Manz (3) and Elschnig (16), there was some pigment present 
in the retinal epithelium, but none at all in the stroma of the iris and ciliary body 
or in the choroid. In the case described by Nettleship (6), the retinal epithelium 
was pigmented, but the pigment was in much less quantity than normally. There 
was some pigment in the choroid, more particularly at the macular region, but 
the stroma of iris and ciliary body was without pigment (Fig. C). Coats (15), 
in the eye of an albinotic negro (Fig. E). found that the iris pigment epithelium 
was brown, considerably lighter than in the normal blue European eye. The 
epithelial pigmentation of the ciliary body was as deep as in many European 
eyes. The pigmentation was very light in the whole of the posterior part of the 
globe. The iris stroma was pigmented, but not the stroma of the ciliary body 
or the choroid (Fig. E). In the inflmt's eyes, Adler and Mcintosh (11) found no 
pigment. They make no special mention of the histological appearances of the 
macula. For two reasons an account of this region would have been of interest. 
In the first place no one has so far recorded the presence of a normal fovea in 
a human albino eyeball — true, in this albino baby a fovea is mentioned as having 
been seen macroscopically — and in the second place there is reason to believe that 
it is to this region particular attention should be given in a search for pigment, 
and that no eye should be pronounced free from pigment until this part has been 
carefully examined. It is well known that in the normal European eye the hexa- 
gonal cells of the retina are darker at the macula than in the parts immi'diately 
surrounding it. Also, the choroidal pigment is frequently dense in this region. 
Again, in an eye of one of the five adult albinos there is a small quantity of 
choroidal pigment principally Icjcated at the macuhi, and in the case to be 
described the only mesoblastic pigment present is situated at the macular region. 
Furthermore, from an examination of eyes froiii twelve dark-race foetuses, and new- 
born and very young infants (see below, pp. 51 — 4), I have found pigment present 
considerably before birth both in the iris stroma, and in the choroid especially at 
* Since this paper was written I have found in the Muenchencr Mediziinsche Wochemchrtft, Nr. 26, 
26 June 1917, S. 84.5, Velhagen's account of a microscopical examination of the eyes of an albinotic man, 
age 2.3. No pigment was present in choroid, stroma of iris, and retinal epithelial layer as far as 
ora serrata. The ciliary body epithelium and posterior surface of iris were pigmented. The macula 
lutea was not differentiated, no fovea was recognised. 
