Pathology of late endothelial failure: Late endothelial failure of penetrating keratoplasty: Study with light and electron microscopy

Purpose. Late endothelial failure of penetrating keratoplasty can be define d as gradual decompensation (increasing thickness with loss of clarity) of a previously clear graft without apparent cause. This study examined the po ssibility that a chronic subclinical rejection process may be occurring in grafts that fail from late endothelial failure, Method, Six patients fulfil ling the diagnostic criteria for late endothelial failure who underwent rep eated keratoplasty were studied. The clinical course and results of specula r microscopy were reviewed. The failed corneal graft for each patient was e xamined by light and electron microscopy. Results. Sequential specular micr oscopy demonstrated low initial postoperative endothelial cell density with continued decrease in density and increase in corneal thickness over the f irst 5 postoperative years. Electron microscopy revealed irregular-shaped c ells of varying size with many abnormal features, lying on abnormal Desceme t's membrane. Degenerating endothelial cells were commonly seen. There was no sign of acute or chronic inflammation. Conclusions. The pathologic findi ngs are suggestive of an unstable and highly stressed endothelial cell popu lation in late endothelial failure but are nonspecific. There was no eviden ce of acute or chronic rejection at the time of graft failure.