Bennett P J, Sekuler A B, Ozin L
Department of Psychology, University of Toronto, Ontario, Canada.
J Opt Soc Am A Opt Image Sci Vis. 1999 Mar;16(3):654-68. doi: 10.1364/josaa.16.000654.
Contrast sensitivity under photopic conditions declines with age; however, the cause of this decline remains unknown. To address this issue, we measured detection thresholds for sine wave gratings in noise, under various conditions of spatial-frequency uncertainty, and estimated observers' internal noise and calculation efficiency. Statistical analyses revealed that efficiencies were lower for old (median age at 68 years) than for young (median age at 22 years) observers; no significant differences in internal noise were found. A control experiment ruled out the possibility that reduced retinal illuminance causes the decline in efficiency with age. Our results demonstrate that age-related neural changes play a major role in the decline in contrast sensitivity with age. Possible contributing mechanisms are considered.
明视觉条件下的对比敏感度会随着年龄增长而下降；然而，这种下降的原因尚不清楚。为了解决这个问题，我们在各种空间频率不确定性条件下，测量了噪声中正弦波光栅的检测阈值，并估计了观察者的内部噪声和计算效率。统计分析表明，年长观察者（年龄中位数为68岁）的效率低于年轻观察者（年龄中位数为22岁）；未发现内部噪声有显著差异。一项对照实验排除了视网膜照度降低导致效率随年龄下降的可能性。我们的结果表明，与年龄相关的神经变化在对比敏感度随年龄下降中起主要作用。文中还考虑了可能的促成机制。
