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.
50/76 page 38
![CHAPTER X. Indications afforded by Mirror and Objf.ct Lens, Indirect Method. [ This method of diag-nosing- Hypermetropia and Myopia was first pointed out by Mr. Hutchinson {Ophih. Hosp. Rep. vol, iv, p. 189) and Mr, Couper {Med. Times and Gaz. Jan. 30, 1869), has shewn how, by it Astigmatism may also be recog-nised. It is desirable that the patient should be under atropine, for otherwise an alteration in the pupil may easily lead to the supposition that the disc has changed in size. Upon seeing a change in the shape of the disc great care is requisite to say whether this is due to an elongation in one meridian or a diminution in the other. In this mode of examination the observer must place ihe oh]eci lens, as close as possible to the patient's eye; then, keeping the optic disc steadily in view, he must gradually withdraw the lens to the distance of a few inches : when— Indication I, If the disc remain the same size throughout, the patient is Emmetropic {vide expl. p. 39), Indication 2. If the disc diminish in size on withdrawing the lens the patient is Hypermetropic, and the more so in pro- portion to the rapidity of diminution {vide expl, p, 40). Indication 3. If the disc decrease in size in one meridian only, the patient is Hypermetropic in that meridian only = Simple hypermetropic astigmatism.](https://iiif.wellcomecollection.org/image/b20405728_0050.jp2/full/800%2C/0/default.jpg)
