Refraction of the eye : its diagnosis and the correction of its errors with a chapter on keratoscopy / by A. Stanford Morton.
- Morton, A. Stanford.
- Date:
- 1882
Licence: Public Domain Mark
Credit: Refraction of the eye : its diagnosis and the correction of its errors with a chapter on keratoscopy / by A. Stanford Morton. Source: Wellcome Collection.
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![viz. : 2-50 D. (xV)> glasses ordered will be (10 D.— 2-50 D.=)-7-S0 D. (i-^=ji] For the various exceptions to these, only very general indications of glasses to be ordered, as well as for the numerous complications of myopia, the reader must be referred to the larger works on this subject. Astigmatism. If the V. cannot be brought up to f (fg) with any spherical glasses, we probably have to do with a case of Astigmatism. In dealing with this error each eye is to be tested separately. If, from the previous examination with the ophthalmo- scope, we have, diagnosed,— (i.) Simple astigmatism, we can proceed to test with the fan of rays. If our surmise has been correct, the patient should now see quite Mstincily, only the line at right angles to his emmetropic meridian, (Chap. V.) If this line were vertical^ it would therefore denote that the meridian paiallel to it Was either hypermetropic or myopic; we should then ascertain what cylinder, with its axis at right angles to this latter meridian is required to correct it: i.e. to render clear the horizontal line. If the correction thus found gives V. = f (fg), it may be ordered for constant use; but if it do not, then, as where none of the rays are distinct, and more particu- larly if first one then another is most clearly seen, we must not hesitate to employ atropine.](https://iiif.wellcomecollection.org/image/b20405728_0063.jp2/full/800%2C/0/default.jpg)
