[Transactions of the American Ophthalmological Society] ; Transactions of the American Otological Society : second annual meeting, Newport, R.I., July, 1869.
- American Ophthalmological Society
- Date:
- [1869]
Licence: Public Domain Mark
Credit: [Transactions of the American Ophthalmological Society] ; Transactions of the American Otological Society : second annual meeting, Newport, R.I., July, 1869. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![accommodation with a smaller degree of convergence than he has been in the liabit of doing; that is to say, till he learns, for • the sake of binocular vision, to oppose the tension on ^hc in- terni by a counterbalancing effort on the part of the extend. The best result wliich can be obtained after a tenotomy is, of eourse, binocular single vision, and this result should always at least be aimed at, even though tliere be a large amount of am- l)lyopia in tlie squinting eye; for, by a correct intersection of tlic visual lines, the combined held of vision of the'two eyes is increased in size, for the images formed u})on tlic retina of the amblyopic eye, though not intense enough to produce real bin- ocular single vision, are yet quite enough to give the ])atient perception of objects situated laterally, and thus free him, to a considerable extent, from the necessity of that continual turn- ing of the head common to those who have only monocular vision. It is indeed asserted that even in its abnormal posi- tion the squinting eye often renders important aid, not only in lateral (pialitative ])ercepti(>ns, but even in increasing the in- tensity of the impressions of the fixing eye. (Oraefe.) There is a great discrepancy among authorities as to the frequency in Avhich binocular vision is obtained after tenot- omy—Graefe and others ])utting the ])erccntage as high as fifty in the hundred in its favor, while Stellwag boldly asserts that binocular single vision is scarcely ever, if ever at all, ob- tained. It is manifest that both these statements are extreme, and that if, on the one hand, Graefe’s statistics arc, as Stellwag claims, made up on entirely untrustworthy data, his own arc deduced from results given by tests which are entirely too severe. I allude to the so-called falling test of llering. It is certaiidy any thing but fair to expect that a person who has * been accustomed, perhaps all his life, to judge of distances with one eye with the assistance of surrounding objects, sliould, when these are excluded, be able, even when using two eyes, to obtain at once, after an operation, as keen a perception of perspective as those who have always possessed binocular vision. Without at present entering further into this subject, I feel convinced that we often obtain a fair, sometimes even a very](https://iiif.wellcomecollection.org/image/b22449784_0034.jp2/full/800%2C/0/default.jpg)
