Atlas and epitome of ophthalmoscopy and ophthalmoscopic diagnosis / by O. Haab.

  • Haab, O. (Otto), 1850-1931.
Date:
1910
Catalogue details

Licence: In copyright

Credit: Atlas and epitome of ophthalmoscopy and ophthalmoscopic diagnosis / by O. Haab. Source: Wellcome Collection.

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    the nasal side, the beautiful pink briglitness of the pupil will be changed to a peculiar grayisli red wlien the eye is illnminated front the nasal side. Secondly, retinal vessels will be seen in the altered pupillary field in the erect image, recognized by the fact that, wlien the observer ntoves bis ltead, they move in the same direction. Tliis local hyperraetropia of the retina can only be due to local ditninution of the distance between the retina and the re- fractive System of the eye, and, therefore, indicates that the ntembrane is displaced or, in other words, that there is a retinal Separation. THE SH ADOW=TEST, OR SKIASCOPY. The discoverer, Cnignet, ealled the method keratoscopy; it is also known as pupil'loscopy and retinoscopy. Tliis method of examination is also best performed vvith the plane mirror, and offers the easicst means of deterniining the refraction. Retinoscopy is the method recommended for any one wlio is unable to determine refraction, and espeeially astigmatism, by the direct method in the man- ner described, if he does not care to nsc Schinidt-Rimpler’s apparatns. It also reqnires practice, however, and is not without inconveniences. In retinoscopy, as in Schmidt- Rimpler’s method, the object is to determine the position of the far point of the eye [point of reversal], sometimes witli the aid of a convex lens, so as to bring the far point to a convenient distance, that is, between the ob- server and the patient. Tliis is espeeially important in low degrees of myopia and in hypermetropia. The far point shonld, if possihle, be brought to a distance of 20 to 40 cm. To determine the optical conditions of the eye linder examination by tliis method, we utilize instead of an image of the eye-gronnd the movement of the illnminated portion of the eye-gronnd as the retinoscope is moved froin side to side. The retinoscope illuminates a certain portion of the eye-ground, and by looking through the opening the observer sees a corresponding