Abstract
Purpose :
To determine the effects of age and simulated optical abnormality on contrast sensitivity (CS) in luminance noise using a novel booklet-based letter CS test.
Methods :
Sixty-eight subjects with no known visual deficits who recently underwent a comprehensive eye exam participated in this study (age range 18-85, with at least 10 subjects per decade between ages 20 and 70 years). Subjects were tested using the right eye only and asked to identify letters that spanned a broad range of Weber contrast (0.001 to 0.56) printed in a novel booklet-based test. The letters were presented against a uniform gray background (no-noise condition) and in the presence of static spatial luminance noise (noise condition), which consisted of light and dark checks. A subset of 5 subjects (age range 26-35 years) performed the same test under three additional conditions: (1) simulated cataract (Simuspecs Blur/Glare Cataract filter #20776), (2) +2 diopters (D) of blur, and (3) low room luminance (illuminance reduction of approximately 20x). CS for these three conditions was compared to the standard condition using paired t-tests with Bonferroni correction (p = 0.05/3).
Results :
In the no-noise condition, contrast sensitivity was independent of age (mean log CS of 1.7) until approximately 54 years, and declined linearly for older subjects (CS loss of 0.1 log unit/decade). CS measured in noise was independent of age across the range of ages tested (mean log CS of 0.9); the slope of a linear regression function fit to these data was not significantly different from 0. Manipulations of simulated cataract and +2D blur significantly reduced CS in the no-noise condition (both p < 0.05/3), whereas these optical manipulations did not significantly affect CS in noise. Reduced room illumination did not significantly affect CS in the presence or absence of noise.
Conclusions :
The results suggest that measurements of CS in luminance noise may be valuable, as these measures appear to be independent of age and certain forms of optical degradation. Furthermore, the results support CS measurements in noise in patients with retina or optic nerve disease, as noise may minimize possible artifacts arising from optical effects such as media opacities or defocus.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.