[Retinal degeneration after intravitreal injection of ornithine. 2. Late change after administration]

The influence of intravitreal injection of a small amount of l-ornithine hydrochloride in monkey eyes has been investigated morphologically. In a previous paper, the author demonstrated that acute selective damage was caused in the retinal pigment epithelium (RPE) by ornithine. This paper will demonstrate retinal degeneration at the late stage by intravitreal injection of ornithine. At one year after administration, sharply demarcated chorioretinal atrophy was seen ophthalmoscopically from the equator to the peripheral retina. These areas corresponded to those where RPE became necrosis at early stage following administration of ornithine. Histopathologically, the photoreceptor cells, RPE, and choriocapillaris disappeared completely in these areas, and the inner retina was directly contact with the Bruch membrane with the proliferating Müller fibers. On the other hand at the posterior pole, the photoreceptor cells, RPE, and the choriocapillaris maintained intact. This study demonstrated that necrosis of RPE by intravitreal injection of ornithine leads to complete loss of the visual cells and choriocapillaris, at the late stage.