[Changes in the intermediate stage of retinal degeneration after intravitreal injection of ornithine]

We reported previously that intravitreal injection of a small amount of 1-ornithine hydrochloride in monkey eyes damages the retinal pigment epithelium (RPE), selectively. At one year after administration, sharply demarcated chorioretinal atrophy was seen. This paper describes the intermediate stage of retinal degeneration caused by ornithine. Two weeks following intravitreal injection of ornithine, RPE cells at the equator became necrotic and disappeared. However RPE regenerated to cover Bruch's membrane at the border of RPE degenerated area. In 2 months at an area where RPE cells disappeared, the photoreceptors and choriocapillaris degenerated to disappear. However, in the area in where RPE regenerated, they maintained their structure. This report demonstrated that damage of RPE resulted in disappearance of the photoreceptor and choriocapillaris.