• In previous experiments, we found that a high-water-content hydroxyethyl methacrylate (Permalens) hydrogel implant was not only well tolerated within the rabbit corneal stroma but also would successfully alter the anterior radius of curvature, and thus the refractive state, of the rabbit eye. The same lens material implanted in the cornea of a patient with aphakic bullous keratopathy was tolerated for six months and decreased epithelial edema but did not alter the refractive state. This cornea, containing the intrastromal lens, was obtained at subsequent penetrating keratoplasty and studied by light and transmission electron microscopy. Morphologically, the epithelium and anterior stroma were not edematous, whereas the stroma posterior to the lens remained edematous. Minimal fibroblastic activity was evident at the lens-stroma interface. There were no signs of inflammation, ulceration, or neovascularization.