Alterations of Descemet's membrane in interstitial keratitis.

Twenty corneas from patients with interstitial keratitis were examined by light microscopy and one of these by electron microscopy. Seventy percent of patients had either a positive serologic test for syphilis or a history of treatment for syphilis. Focal or diffuse multilaminar thickening of Descemet's membrane with secondary linear guttata was present in 88% of cases. Confluent linear cornea guttata formed retrocorneal hyaline ridges that clinically showed a central gray core surrounded by a translucent sheath. Microscopically, these ridges consisted of concentric laminations of newly formed Descemet's membrane. Some ridges hung into the anterior chamber as a bow-like strand or a spiderweb network. A possible pathogenetic sequence may include (1) inflammatory insult to a relatively young endothelium; (2) alteration of endothelial function to fibroblast-like activity; (3) the production of abnormal basement membrane and other collagenous material and formation of a new multilaminar Descemet's membrane; and (4) separation of some ridges from the multilaminar Descemet's membrane to hang into the anterior chamber as strands and networks.