[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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![2C In summing up the remarkable points of this case Schwcig- ger mentions, as two of its individual peculiarities, that under the influence of binocular single vision the previously existing latent hypermetropia became manifest, and that the relative accommodation was displaced. I cannot think that these are by any means individual peculiarities of this particular case, as I have myself not unfrequcntly seen the latent hypermetropia become manifest after the operation, but have also occasionally seen the displacement of the relative accommodation, and be- lieve that we should sec it oftencr if we examined carefully for it immediately after the operation; but the fact is, it is a much rarer thing to obtain real binocular single vision in a case of marked strabismus than we should be led to suppose from the books. I cannot think that results as remarkable as those mentioned in Schweigger’s case and the one just described can be the result of cliance, but believe tliat they are due to the common law which governs the connection between con- vergence and accommodation. It seems to me that these two cases offer a beautiful example of the law sought to be established in my former paper, that for every increased tension of the ciliary muscle there is a cor- responding and contemi)oraneous tension imparted to the in- terni. For, provided that accommodative efforts ceased, and the ciliary muscle consequently entirely relaxed, the extern!, stimulated by the instinctive desire for binocular vision, had force enough to obtain the proper position of the optical axes, but not enough to maintain it, under the action of the ciliary muscle; for the slightest attem])t to accommodate the eye, even for parallel rays (lit. being only 1-30), at pnee destroyed bin- ocular vision, producing convergent strabismus. This cer- tainly could not have been the case had the tension of the ciliary muscle been independent of—that is to say, capable of being disassociated from—the intern!. And I believe in all cases where binocular vision has been obtained from a condi- tion of marked strabismus, that the reason why *it is perma- nently maintained is not because the tension of the ciliary muscle is disassociated from that of the intern!, but because the tension, imparted to them under accommodative efforts which would turn the eye in, is counterbalanced by the extern!,](https://iiif.wellcomecollection.org/image/b22449784_0032.jp2/full/800%2C/0/default.jpg)
