Ocular contributions to age-related loss in coarse stereopsis.

PURPOSE To determine the basis for the dramatic decline in coarse stereopsis that occurs with age. METHODS The Frisby test was used to assess stereopsis in a large sample of randomly selected persons over the age of 58 years. A number of other vision functions were also assessed in the same persons. The data were used to address the question of whether the decline in stereopsis reflects age-related alterations in cortical stereopsis mechanisms themselves (e.g., disparity detectors) or a degradation of the signal reaching the cortex as a result of alterations in earlier visual components. Two of three vision measures were binocular and thus reflect predominantly the function of the better eye. RESULTS We find, as many others have reported, that even very coarse stereopsis declines dramatically with age. Despite not having separately assessed each eye, we find that among those selected to have good ocular function there was no significant decline in coarse stereopsis with age. CONCLUSION These findings suggest that the enormous decline in coarse stereopsis with age can be accounted for by alterations in early stages of vision processing.