Light effect on the synaptic organ of the rat

The photoreceptor synapses of albino rats show considerable pathologic changes following fluorescent light exposure. The changes in the synapses and in the lamellar membranes of the outer segments occur and progress simultaneously. Membranes proliferate in the paramitochondrial zone of the rod synaptic spherule and fine budding of the smooth endoplasmic reticulum occurs in the cone pedicle within one hour's exposure to the brightness of 500 foot candles. Proliferating paramitochondrial membranes have no cytochrome c oxidase activity and degenerate together with mitochondria by further exposure. The cone pedicles remain relatively intact in photically damaged retina.