Abstract

Previous studies have demonstrated loss of retinal function with increasing age in the absence of disease. The short-wavelenght sensitive cone pathways have been shown to be particularly vulnerable to aging effects (eg. Haegerstrom-Portnoy, et al., 1989; Werner and Steele, 1988; Johnson et al., 1988). A potential cause of neural loss with age is visible light exposure over a lifetime. The ocular photochemical light damage action spectrum shows an exponential rise with decreasing wavelength (Ham et al., 1976). One possible method to determine if a life-long exposure to visible light contributes to neural loss is to examine S-cone sensitivity across the retina. If light contributes to damage, the fovea may show less damage due to the protective role of the yellow macular pigment. In a previous study (Haegerstrom-Portnoy, 1988), I showed that the S cone loss with aging was not evenly distributed across the retina but that parafoveal locations showed considerably more loss, consistent with the hypothesis that macular pigment protects the fovea from light damage. The purpose of the present study is to strengthen this argument. Macular pigment density is very variable at any one age (e.g. Pease et al., 1987) but shows no significant change with age in cross-sectional studies beyond age 2 years (Bone et al., 1988). If macular pigment does protect the fovea, there should be a direct relationship between macular pigment density and the foveal/parafoveal difference in S cone sensitivity. The results of this study shows that such a relationship indeed exists.

© 1992 Optical Society of America