Two of six patients (four women and two men ranging in age from 51 to 90 years) with bilateral senile iridoschisis also had secondary unilateral narrow angle or angle-closure glaucoma. All six patients had splitting of the iris stroma inferiorly. Histopathologic studies disclosed marked iris stromal atrophy without evidence of vascular or neural alterations. Vessels were present in the separated anterior stroma. Electron microscopy of iridectomy specimens from three patients and a corneal button from one disclosed scant or absent collagen fibrils in the area of separation. The cornea showed focal loss of endothelial cells, patchy posterior banding (110 nm) of Descemet's membrane, and stromal and epithelial edema. The posterior corneal surface showed degenerated endothelial cells and irregular connective tissue most marked inferiorly; the endothelial cells appeared to be normal.