Visual Performance on the Small Letter Contrast Test: Effects of Aging, Low Luminance and Refractive Error
ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER AL
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In this study the visual performance of aviators and a myopic, non-aviator group were compared to determine the effects of aging, available light and refractive error. The chart used is a novel chart called the Small Letter Contrast Test SLCT which measures sensitivity to contrast at the moderate to high end of the spatial frequency range near the visual acuity thresholds of most normal observers. All three variables influence visual performance on the SLCT, age having a greater effect on low luminance performance and refractive error having comparable effects on SLCT performance regardless of luminance level. High contrast visual acuity remains fairly stable and normal over the age range tested however it decreases with increasing refractive error.
- Anatomy and Physiology
- Medicine and Medical Research