منابع مشابه
Scotopic sensitivity during adulthood
Older adults typically exhibit about a half log unit loss in scotopic sensitivity that cannot be attributed to optical factors and retinal disease suggesting a neural origin. Little is understood about the developmental course of this neural deficit as to whether it first appears in late life or gradually emerges during the course of adulthood. To address this developmental issue, scotopic sens...
متن کاملAging and scotopic sensitivity
Scotopic sensitivity was compared in young and older adults in good eye health after individualized correction for age-related changes in lens density and control of pupil diameter. Unlike earlier studies on this topic, fundus photography and a grading scale were used to characterize macular health in the older sample. Twenty-four young adults (mean age 27) and 25 older adults (mean age 70 year...
متن کاملThe development of scotopic sensitivity.
UNLABELLED PURPOSE. Test the hypothesis that the developmental increases in rod photoreceptor sensitivity and rod-mediated visual sensitivity at 10 degrees, 20 degrees , and 30 degrees eccentric are concurrent. It is known that maturation of the parafoveal (10 degrees eccentric) rod outer segments and visual sensitivity is delayed compared to that at 30 degrees eccentric. METHODS Rod isolated...
متن کاملSenescent changes in scotopic contrast sensitivity
Scotopic contrast sensitivity functions (CSFs) were measured for 50 observers between the ages of 20 and 88 years. Using a maximum-likelihood, 2-alternative, temporal forced-choice threshold-estimation algorithm, scotopic CSFs were measured at 7 spatial frequencies ranging from 0.2 to 3.0 cpd, with mean retinal illuminance equated for observers at -0.85 log scotopic Trolands. For each stimulus ...
متن کاملHuman scotopic sensitivity is regulated postreceptorally by changing the speed of the scotopic response.
Sensitivity regulation enables the visual system to function effectively from the absorption of a few photons at the lowest visual threshold to the absorption of enough photons to bleach nearly all the light-sensitive photopigment in the eye. Here, we investigate sensitivity regulation in the rod (or scotopic) range from -3.8 to -0.8 log(10) scotopic trolands. Over most of this range, the rate ...
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ژورنال
عنوان ژورنال: Vision Research
سال: 2000
ISSN: 0042-6989
DOI: 10.1016/s0042-6989(00)00108-5