A comparison of binocular summation in young and older patients.
Binocular and monocular contrast sensitivities were measured at two spatial frequencies of 1 and 6 c/deg in 8 young (mean age 22.6 +/- 3.8 years) and 18 older subjects with normal healthy eyes (mean age 58.4 +/- 7.3 years). Data were analysed as binocular summation ratios defined as binocular CS/"best eye' CS. Binocular summation ratios were higher for the younger group (1.46 and 1.48 for 1 and 6 c/deg respectively) compared to the older group who demonstrated a spatial frequency dependence (1.31 and 1.13 at 1 c/deg and 6 c/deg respectively). The results are discussed in terms of age-related cortical cell loss and increased monocular sensitivity differences between the two eyes.
Pardhan
S
S
Department of Optometry, University of Bradford, West Yorkshire, United Kingdom.
D000328:Adult; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D012684:Sensory Thresholds; D015348:Vision, Binocular / Q000502:physiology*; D015349:Vision, Monocular / Q000502:physiology