In order to analyze the association between retinal vascular degeneration and hereditary visual cell dystrophy, high-intensity light and iodoacetate were used to selectively destroy visual cells and pigment epitheluim; both cell populations were destroyed in the former but only the visual cells in the latter. It was found that visual cell destruction after exposure to damaging light in the rat is followed by capillary degeneration after a minimal latent period of two weeks. Additional exposure to damaging light produced more widespread, but not more severe, vascular degeneration. Iodoacetate administered intravenously in cats induced visual cell destruction followed quickly by very severe and widespread capillary degeneration. Results are interpreted to show that capillary degeneration occurs secondary to visual cell loss. This degeneration does not appear to be related in a primary way to the state of the inner nuclear layer or the pigment epithelium.