Atlas of the external diseases of the eye : including a brief treatise on the pathology and treatment / by O. Haab ; edited by G. E. de Schweinitz.

  • Haab, O. (Otto), 1850-1931.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Atlas of the external diseases of the eye : including a brief treatise on the pathology and treatment / by O. Haab ; edited by G. E. de Schweinitz. Source: Wellcome Collection.

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

    32/310 (page 32)
    surface is evidently opaque at this point, it looks as if it had been breathed upon, and, like a moist window-pane, is a poor reflector. Opacities of this kind usually corre- spond to inflammatory areas. Opacity of the entire cornea indicates either a general inflammation or glau- coma. The precise nature of such an opacity will be described later; for the present, suffice it to say that in many cases this opacity alone should lead us at least to suspect glaucoma, and may point the way to a correct diagnosis; we therefore emphasize the importance of noting accurately the reflecting powers of the cornea. 2. The image of the window-bars may be perfectly clear and distinct, but the distortion may be greater than normal. It may be limited to a portion of the image, or it may be general. In the first case the distorted por- tion of the image is usually found to correspond to an area which, although smooth, is either depressed below, or elevated above the general level, or presents a plane surface. The latter condition is sometimes called a facet. The distortion may be general. Two conditions are possible. Either the entire surface is rough and irregular, or beset with numerous facets, as, for instance, after repeated ulcerations; or, more rarely, the general distor- tion of the image is due to incorrect curvature of the entire cornea, giving it a more or less conical shape, a condition termed keratoconus. The image is very small at the apex of the cone and increases in width as it approaches the corneal margin, where the lateral portions of the membrane (between the center and the margin) take part in the reflection. Keratoconus is a serious dis- turbance to vision ; it is most surely recognized by observ- ing the nature of the corneal image—another reason for training the eye in the study of corneal changes. 3. Under certain circumstances opacity may be com- bined with irregularity of the surface, as, for example, more or less rough depressions from recent ulcers, or opaque elevations from imprisoned foreign bodies, or a