The acromeres of the cones and the rods become disorganized, and the internal segments fill with refractant bodies, presumably lipofuscin. The dislocation and partial loss of photoreceptor nuclei happens without significant modifications to the RPE, the Bruch's membrane, and the choriocapillaries (Curcio et al., 1993). Gao and Hollyfield
(1992) suggest that the loss of rods begins early in adult life, and the density of cones diminishes gradually in the extreme retinal periphery. On the contrary, Curcio et al.
(1993) affirm that there is no evidence of a reduction in the density of the foveal cone peaks, although the interperson variability is high. The loss of foveal photo-receptors begins to manifest itself in persons over 90 years old. As previous studies haven't precisely specified the anatomic location of the observed zones of the retina, it was difficult to confront the changes in retinal anatomy with age-related changes in visual function. Curcio et al. (1993) have examined, using digital computer imaging, the topography of the retina of healthy eyes of people divided into four groups by age: Group 1 (27-37 years), group 2 (44-58 years), group 3 (61-75 years), and group 4 (82-90 years) in order to distinguish paraphysiological changes resulting from aging and/or from pathological changes. It was seen that in the central 43° of the ocular retina studied, rods but not cones are lost during the course of the life.
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