The harmonius symmetrical action of the oblique muscles in all cases of oblique astigmatism : read before the Nashville Academy of Medicine, January 15, 1891 / by G. C. Savage.

  • G. C. Savage
Date:
[1891]
Catalogue details

Licence: Public Domain Mark

Credit: The harmonius symmetrical action of the oblique muscles in all cases of oblique astigmatism : read before the Nashville Academy of Medicine, January 15, 1891 / by G. C. Savage. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    in myopic astigmatism, for the location of the axis of the cylin- der is always the reverse of that for hypermetropic astigma- tism—I mean where there is doubt between any two points. Each of the two eyes in which, there is oblique astigmatism having thus been carefully corrected the proper glasses are ordered. When the patient begins to wear them his binocular single vision is nearly always disturbed by an apparently changed codition of objects, a rectangle no, longer appearing to be such, and a level surface seems to incline. Some times the changes are so marked as to make the patient very uncomfortable. This metamorphopsia (so termed by Dr. Lippincott, of Pittsburg,) may continue u. few hours, a day, a week or a month, but in the end is certain to disappear. It is due to a continuation of the old habit of rotation, when both eyes are used, and a conse- quent loss of coincidence of the best meridians and the axes of the cylinders. Whenever this now unnecessary habit of rotation is broken, be it soon or late, sudden or gradual, the metamor- phopsia ceases. The different forms of metamorphopsia can be demonstrated artificially. Four years ago I said that in cases of oblique astigmatism the eyes were made to rotate by means of the oblique muscles ; I repeat the assertion to-day with emphasis, but with this modi- fication: I then thought the rotation was effected by the har- monious non-symmetrical action of the abliques, but in this paper I have demonstrated that the rotation is brought about by the harmonious symmetrical action of the obliques and, too, have shown why the rotation is necessary. The only papers ever published, touching this quo^stion, so far as I know, except my own already ]-eferred to, are: one on Binocular Astigmatism by Dr. li. Culbertson, in the Journal of the Association, Nov. 3,1888 ; and one on Metamorphopsia by Dr. J. A. Lippincott, in the Archives of Ophthalmology, March, 1889. The latter is a valuable paper and shows the Doctor to be a close observer as well as a ready Avriter. In his paper he incidentally refers to the obliquity of the retinal image in oblique astigmatism but does not advocate the doctrine of rotation.
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