Drusen-like deposits in the outer retina of Japanese quail

Histological examination of the outer retina of Japanese quail (Coturnix coturnix Japonica) ranging in age from 4-48 months revealed the presence of drusen-like deposits which closely resemble those described in primate and human retinas. At both light and electron microscopic levels, these deposits were characterized by randomly distributed, granular and heterogenous materials. Larger deposits with pleomorphic inclusions, often globular in shape, occurred more frequently in older quail, particularly in males. An increase in the incidence and size of drusenoid deposits occurred with increasing age, with a greater rate of accumulation in males than in females. Previously, we have shown that retinal pigment epithelial lipofuscin increases more rapidly with age in female quail and that cumulative light damage is associated with increased lipofuscin in females but not in males. In the present study, no increase in drusen-like deposits was observed in single light-damaged or double light-damaged retinas of either sex. Thus, lipofuscin and the frequency and size of drusenoid deposits do not appear to be directly linked, although both increase with age in both sexes.