Mechanisms of visual loss in corneal edema.

Although visual disability from corneal edema is a well-recognized clinical finding, it is not easily confirmed by routine visual assessment. A more reliable assessment of visual changes resulting from corneal edema of varying origins is achieved by measurement of changes in the contrast sensitivity function. The measurements can be sensitized by the presence of a glare source to allow a more accurate determination of the nature of the visual loss. Even in the absence of a measurable loss of visual acuity, corneal edema leads to diminished visual function. The magnitude and type of this loss is dependent on the origin of the edema and the site of the corneal response.