Ketamine-induced ultrastructural changes in the retina.

The author studied the retinal changes induced by ketamine in animal experiments. Ultrastructural changes were observed in the inner segment of the photoreceptors, in the three nuclear layers, and in the nerve fiber layer following ketamine monoanesthesia of 60 min duration. A pronounced destruction of the Müller's cells nourishing the nervous elements was seen. Three days after the anesthesia, remarkable regression of the neuronal changes and extreme accumulation of glycogen in the Müller's cells occurred. These phenomena, as well as some other ophthalmological side effects, were explained with the development of relative retinal hypoxia due to the increased oxygen metabolism which was caused by the ketamine anesthesia.