A manual of examination of the eyes / by E. Landolt ; translated by Swan M. Burnett ; revised and enlarged by the author.

  • Landolt, E. (Edmond), 1846-1926.
Date:
1879
Catalogue details

Licence: Public Domain Mark

Credit: A manual of examination of the eyes / by E. Landolt ; translated by Swan M. Burnett ; revised and enlarged by the author. Source: Wellcome Collection.

    305/340 (page 301)
    LECTURE XXIY. SOURCE OF ILLUMINATION. EXAMINATION BY THE OBLIQUE LIGHT. Gentlemen:—We have a word more to say in regard to the source of ilhcmination for ophthalmoscopy. It is evident that the ideal illumination is that of the sun. It is not only the most intense—which, however, is not always an advantage in ophthal- moscopy—but the light is white, and shows us objects in their true color. We always employ daylight, wherever it is possible, but most frequently we are compelled to have recourse to artificial light. In order to have daylight at our disposal we make an opening in the shutter. The room must be dark and the light entering through the opening must be the only light in the room. To make an ophthalmoscopic examination the patient is placed with his back toward the window, to the right or left of the opening. This light, though not so strong as that of a large lamp, is jet sufficiently strong for the examination of the fundus, and possesses notable advantages over the artificial light, among them the important one which we have mentioned, that we are enabled to better distinguish the shades of coloration of the fundus, which renders the diagnosis much more precise than when the examina- tion is made by artificial light, which is always red. I cannot too strongly recommend to you the employment of daylight in ophthal- moscopic examinations. It is hardly necessary to say that daylight has the same advan- tages in examinations by the oblique light, as with the ophthalmo- scope.