Progressive rod-cone degeneration in the dog: characterization of the visual pigment.

The visual pigment of dogs affected with progressive rod-cone degeneration was compared with that of normal dogs. Absorption spectra from detergent extracts and from intact photoreceptors showed no significant difference between normal and affected animals in the shape of the absorption spectrum, the wavelength of maximum absorbance (gamma max = 506 nm), or the total amount of pigment in the eye. A difference was observed in the distribution of pigment extracted from the retina and from the pigment epithelium-choroid complex of one animal judged from the morphologic appearance of the retina to be more severely affected.