RETINAL PHOTORECEPTOR DENSITY DECREASES WITH AGE

Purpose: To evaluate the effect of age on the density of retinal photo receptors in humans, Methods: Fifty-five normal eyes from human donors , with a mean age of 58.7 +/- 19.1 years and an axial length of less t han 27 mm, were examined. After opening of the globes by a 16-mm corne oscleral trephination, 25 retinal tissue samples were obtained in four meridians. The photoreceptors were counted on photographs taken from the photoreceptor inner segments after sonographic removal of the oute r segments. The cones in the foveal center could not be evaluated. Res ults: Outside the foveal center, the photoreceptor density decreased s ignificantly with increasing age. In absolute and relative terms, the decline was more marked for the rods (mean rod loss, 236 +/- 63 cells or 0.37% +/- 0.10%/mm(2) and year of a mean density of 62,987 rods/mm( 2)) than for the cones (mean cone loss, 5.90 +/- 0.68 cells or 0.18% /- 0.02%/mm(2) and year of a mean density of 3320 +/- 578 cones/mm(2)) . For both cones and rods, the cell loss was more marked at an eccentr icity of approximately 5-8 mm than in the retinal periphery at an ecce ntricity of 14 to 20 mm. There were no significant differences between the superior, inferior, temporal, or nasal meridian nor between women and men, Conclusions: The photoreceptors decrease in density with inc reasing age. The annual cell loss of approximately 0.2% to 0.4% is sim ilar to the age-related loss of retinal ganglion cells and pigment epi thelium cells. The decline in photoreceptor count affects more rods th an cones. It does not prefer special age groups. It is more pronounced at an eccentricity of 5 to 8 mm than in the retinal periphery at an e ccentricity of more than 14 mm. It may be important for an age-related decrease in visual functions and for diseases affecting the photorece ptors in elderly patients.