Threshold vs. intensity (tvi) functions were measured under conditions in which the slope of the rising branch approximated the deVries-Rose law in order to evaluate the contribution of intrinsic visual noise (dark light, Eigengrau) to age-related elevations in threshold under photopic conditions. Data were obtained from 48 observers (20-88 years) using a temporal 2AFC procedure. The stimulus was centered at 8° nasal retinal eccentricity and consisted of a 560 nm, 14.4' test flash (10 ms) concentric with a steady 500 nm (12.9°) adapting field (13 intensity levels ranging from 0-9 log quanta · sec(-1) · deg(-2)), which resulted in clear scotopic and photopic branches. Photopic thresholds increased linearly with age at a rate of 0.08 log unit per decade at the cornea. The mean slope of the rising portion of the tvi functions (in log-log coordinates) was 0.62, and not correlated with age. Dark light values increased with age, but not significantly. Dark light was a statistically significant predictor of individual differences in absolute photopic threshold, but it is not responsible for age-related increases in threshold under photopic conditions.

中文翻译：

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与年龄相关的明视增量阈值的增加不是由于固有噪声的升高。

在上升分支的斜率接近 deVries-Rose 定律的条件下测量阈值与强度 (tvi) 函数，以评估固有视觉噪声（暗光，Eigengrau）对阈值年龄相关升高的贡献适光条件。使用时间 2AFC 程序从 48 名观察者（20-88 岁）获得数据。刺激以 8° 鼻视网膜偏心率为中心，由 560 nm、14.4' 测试闪光 (10 ms) 同心和稳定的 500 nm (12.9°) 适应场组成（13 个强度级别，范围为 0-9 log 量子·秒(-1) · deg(-2))，导致清晰的暗视和明视分支。角膜的明视阈值随着年龄的增长以每十年 0.08 log 单位的速度线性增加。tvi 函数上升部分的平均斜率（在对数坐标中）为 0.62，并且与年龄无关。暗光值随年龄增加而增加，但不显着。暗光是绝对明视阈值个体差异的统计学显着预测因子，但它不是明视条件下阈值随年龄增加的原因。