Changes in rod sensitivity through adulthood.

Absolute thresholds of 23 subjects 19-61 years of age were determined for three wavelengths at six retinal eccentricities in the horizontal meridian (2.5 degrees-30 degrees). The raw data were corrected for prereceptoral light losses that may be age-dependent. Lens density was estimated for each subject by comparing scotopic spectral sensitivity with the absorption spectrum of rhodopsin. Macular pigment density was estimated by comparing macular sensitivity with peripheral sensitivity. Average dark-adapted pupil size at each age was taken from published values. After correction for these prereceptoral light losses, changes in rod sensitivity with age were not significant at any retinal locus tested.