Abstract Purpose: To develop a retinal degeneration model with selective photoreceptor loss and RPE sparing, to be used as recipient for evaluating retinal transplants.
Methods: Albino rats were exposed to blue light, continuously, for 1–7 days (24–168 h) in a specially designed cage. Eyes were histologically analyzed at periods between 2 h and 8 months after the light exposure. Electroretinograms (ERGs) were recorded from some rats at 12–216 days after exposure. Using
behavioral methods, visual thresholds of some rats were determined before exposure and re-measured between 18 and 52 days following exposure. Results: Apoptotic nuclei appeared exclusively in the photoreceptor layer after 1–5 days exposure to blue light. Light microscopy revealed that 2–4 days of light exposure reduced the outer nuclear layer (normally eight to ten rows) to 1 row of cells in the central retina and to two to three rows in the periphery,
both in the superior and the inferior retina. Average ERG a- and b-wave amplitudes of light-damaged rats were both reduced by about 98%. Visual performance in the behavioral test was substantially impaired.
Conclusions: Continuous exposure of albino rats to moderate blue light for 2–5 days selectively eliminates most of the photoreceptors while leaving the RPE initially intact.