36 



THE FUNDUS OCULI OF BIRDS 



To this end the assistant must, at first, quietly 

 but firmly hold the mandibles with one 

 (gloved) hand, the other pressing claws and 

 wings against his chest. In a few minutes 

 the bird ceases to struggle; the assistant's 

 grasp of the bird is then slowly relaxed; the 

 bird relaxes its muscles, no longer resists the 

 attempt to examine it and the head can 

 usually be turned in any desired direction 

 to suit the observer. See Fig. 23. 



There is sometimes difficulty in seeing the 

 fundus of the bird because of frequent wink- 

 ing of the bird's nictitating membrane (rarely 

 through shutting of the true lids) and because 

 of occasional contractions of the pupil (unless 

 it is artificially dilated) but these difficulties 

 are, with time and patience, surely overcome 

 — and almost always without damage to the 

 bird, the observer or his assistant. Some 

 birds, Cormorants, for instance, resist at- 

 tempts to quiet them and become wild and 

 restless when the light from the ophthal- 

 moscope falls on the macular region; others, 

 like the Raven, remain quiet for irregular 

 periods during the examination but intel- 

 ligently await an opportunity to use bill and 

 claw on the captor. 



As an extended study of the eyes of living 

 birds is not without its dangers, both the 

 student and his assistant should wear leather 

 gloves during the ophthalmoscopic examina- 

 tion and should especially be on guard against 

 facial bites, stabs and scratches — from the 

 mandibles and talons of Raptores and Par- 

 rots in particular. In addition to these acci- 

 dents, one of the writer's assistants was severe- 

 ly bitten by a European Raven, another was 

 badly kicked by an Ostrich, while the writer 

 himself barely escaped the loss of an eye from 

 a stab on the margin of the orbit inflicted 

 by the pointed beak of a Little White Heron. 



Reference is elsewhere made to the possi- 

 bility of quieting or even of hypnotizing birds 

 for the purpose of making an ophthalmoscopic 

 examination. In some cases flashing the 

 light of the ophthalmoscope into the animal's 

 eyes produces a quieting effect. 



The writer has had many such experiences 

 but he here relates only one. Assisted by 

 Head-Keeper Pitts of Bentley's California 



Ostrich Farm and several San Diego col- 

 leagues he examined, in 1912, a young, adult 

 ostrich, six feet high, healthy and very vigor- 

 ous. The bird resisted capture and was thrown 

 only after a struggle. A keeper sat on his 

 prostrate body; another held his head and 

 neck. After the light of a self-luminous 

 skiascope had played over his dilated pupils 

 in a darkened room for about five minutes 

 he acted as if he were in a trance ; he remained 

 in the prone position without being held and 

 a complete examination of his pupil reflexes, 

 static refraction, fundus appearances, etc., was 

 made without difficulty. Finally, after about 

 20 minutes or half an hour (when this inquiry 

 was completed) the bird refused to move or 

 rise — and had to be pushed to his feet — after 

 which he became his lively self again. 



The small pupils of Wrens, Nuthatches, the 

 smaller Warblers, Hummingbirds, etc., even 

 when fully dilated, make it extremely difficult 

 to view the fundus during the life of the bird 

 and tax the perseverance of the observer to 

 the utmost. It is, perhaps, well not to at- 

 tempt such tasks until the ophthalmoscopist 

 has had a year or two of experience. Annoy- 

 ing, also, are the fugitive reflections and 

 "shot-silk" colors that play over the retinal 

 areas in some birds, but even these fail to 

 obscure the fundus picture after some months 

 of practice. 



The task of picturing the avian background 

 for the purpose of conveying an intelligent idea 

 of its appearance is a serious one; indeed, with 

 all the work done upon the eyes of Birds, this 

 method has been almost entirely neglected. 

 The ophthalmologist may be a good observer 

 but a poor artist; conversely, an expert in the 

 use of brush and pencil may not be sufficiently 

 conversant with normal and pathological, 

 human and comparative ophthalmoscopy and 

 ophthalmology to enable him to make an in- 

 telligent use of his artistic talents. These 

 difficulties have been, in this research, largely 

 met by an arrangement with Mr. Arthur 

 Head, F. Z. S., the well-known London artist, 

 who for some 20 years past has been painting 

 both human and animal fundi for confreres 

 here and abroad. This artist and the writer 

 have together examined and discussed in the 



