Keratoconus and tapetoretinal degeneration.

In a series of 233 keratoconus cases, electroretinograms (ERGs) and visual evoked responses (VERs) were recorded; the results of this study are discussed. In six cases, the ERGs were extinguished, and the VERs were pathologic. In contrast to this, in four cases, ERGs were normal, but VERs were pathologic. Postoperatively the electrophysiologic findings remained the same, and the ophthalmoscopic examination of the eyes revealed the existence of a diffuse tapetoretinal degeneration or a macular lesion. These data show clearly the coexistence in many cases of keratoconus with diffuse tapetoretinal degeneration or macular lesion. The preoperative value of an electrophysiologic study of keratoconus patients is justified to avoid an unneeded corneal transplant.