Abstract
Exposure of adult, albino rats to fluorescent and incandescent illuminance causes photoreceptor degeneration, which is followed by active phagocytosis of the fragmented cells. Male and female rats from 3 weeks of age to adulthood were exposed to a lighting schedule and an elevated environmental temperature known to induce receptor destruction in adult animals; control groups were exposed to cyclic lighting and room temperature. Retinas of 3- and 4-weekold experimental animals were apparently unaffected by light exposure. Outer and inner segments were fragmented and receptor nuclei were pyknotic in localized areas of the central retina of some 5- and most 6-week-old rats; areas of focal damage were more severe in 7-weekold rats. At 8 weeks of age, the reduction in average thickness of the outer nuclear layer (ONL) first became statistically significant. Thereafter, photoreceptor destruction and reduction in OLN thickness became progressively more severe as the rats aged. Reduction in the overall thickness of the retina as a result of light exposure was not as impressive as the effect on the ONL. Photoreceptor damage apparently was not influenced by the animal's gender.