[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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![moved, and these muscles are then left at liberty to bring forth their power in order to maintain binocnlar single vision, as soon as this is threatened by placing ])risms before the eyes with the angle outward. It often ha])pens that the effect of glasses in increasing, at least to its fullest extent, the abduetivc force in by])ermetro])ic eyes, is not always obtained at once, even in cases where the externi arc not idio])atiiically weak. It often takes some little time for the eyes to give up the exercise of a certain amount of tension, the employment of which habit has rendered in- stinctive. On account of this low degree of aljductive ])ower an ex- amination should be made (alter the hypermetropia has been neutralized as far as jmssiblej into the condition of the mus- cles, and if a marked degree of insufficiency of abduction is shown, a tenotomy is, in my opinion, not only justiiiablc, but necessary, notwithstanding the fact that no actual strabismus exists, and the weight of Donders’ opinion against it.‘ The cases requiring operative interference will, of course, be com- jiaratively rare, and the tenotomy must be done, not with the idea of disjiensing with the ]>ro])('r correcting glasses, which was l)onders’ chief objection to it, but with the aim of restor- ing a normal equilibrium to the muscles. The next subject which I shall call your attention to, and which 1 have now only time to briefly touch upon, is the action of the relative accommodation in divergent squint and weak- ness of the interni, and, as it is in myopic eyes that these affec- tions most fre(|uently occur, my remarks will in a great meas- ure be restricted to that condition. In myo])ia the relative accommodation is dis})laced toward the near jioint, which is exactly the reverse of what it is in hypermetropia, or, what amounts to the same thing, the ])ro- portion of accommodative force actually used is always greater in myopia than in emmetropia; consequently the tension on the ciliary muscle is always less, while that on the interni is, from the shape of the eye, always greater for a given convergence than in the normal organ. From this it results that the .ab- ductive force is, as a rule, disproportionately great; and, as you arc well aware, the first indication in the treatment of in-](https://iiif.wellcomecollection.org/image/b22449784_0046.jp2/full/800%2C/0/default.jpg)
