Abstract
Purpose: Contrast sensitivity (CS) is considered the most comprehensive single measure of human spatial vision. Although solid data exist for CS in the near periphery (0 to 20o), few studies have examined CS at greater eccentricities and even fewer have employed Gaussian filtered sine waves (Gabor patches) which provide both reliable measurements and relative freedom from detection artifacts. In addition to a better understanding of retinal and neural mechanisms, establishing normative CS data across a broad range of eccentricities provides help in the assessment of eye diseases which target peripheral vision (e.g. glaucoma, RP, retinal degeneration). Methods: Right eyes from 20 young adults were tested with vertically-oriented sinusoidal Gabor patches that ranged logarithmically in spatial frequency (SF) from 0.375 to 18 cy/deg and in contrast from 0.001 to 0.30. Contrast thresholds at each SF were obtained foveally and from 100 to 800 within the temporal visual field. Testing was repeated 3 to 5 times for each adult. Results: CS was highest with central vision (M (across SF) = 145.9) but declined progressively at 100 (M = 57.1), 200 (M= 37.4), 400 (M=15.3), and 600 (M= 5.6). No consistent responses were obtained at 800. Across all eccentricities, CSFs displayed the typical inverted-U shape but peak CS shifted progressively to lower SF. Repeated measurements were highly consistent across all SF (r = 0.62 to 0.85). Conclusions: CS can be measured reliably up to at least 600 in the periphery. Spatial functioning decreases by about 0.24 log units per 10o across the periphery with the rate of reduction relatively greater for higher spatial frequencies. Overall, these psychophysical data are consistent with anatomical and physiological data describing the relative ratios and efficiency of P-cells in the peripheral retina.
Meeting abstract presented at VSS 2015