AGE-RELATED-CHANGES IN BINOCULAR VISION - DETECTION OF NOISE-MASKED TARGETS IN YOUNG AND OLD OBSERVERS

This study investigated the effects of age on binocular unmasking. Thi s term denotes the fact that a visual signal embedded in noise is dete cted appreciably better when the stimulus complex contains interocular cues (dichoptic condition) than when such cues are absent (binoptic c ondition). Detection thresholds for two Gabor signals differing in spa tial frequency were determined in young and old adults with no identif iable ocular pathologies. The signals were embedded, in both condition s, in two-dimensional Gaussian noise. Binocular Masking Level Differen ces, defined as the difference between the binoptic thresholds and the dichoptic thresholds, did not change with age; however, the older adu lts showed higher binoptic thresholds with both signals and higher dic hoptic thresholds with only the lower-spatial-frequency signal. For bo th groups, binoptic and dichoptic thresholds increased with spatial fr equency. The implications of these results are discussed.