THE EFFECTS OF AGE AND OCULAR HEALTH ON LETTER CONTRAST SENSITIVITY AND HIGH AND MEDIUM CONTRAST ACUITY AS A FUNCTION OF LUMINANCE

1. The purpose of this study was to examine the effects of age and ocular health on letter contrast sensitivity and on high and medium contrast acuity as a function of luminance. All subjects were recruited and tested either at senior citizens' centers or at the vision laboratory, Syracuse University. Two experiments were carried out. 2. In the first experiment, 46 elderly volunteers (mean age 72.5 yr) with self-reports of good ocular health, 33 elderly volunteers (mean age 73.2 yr) with self-reports of eye disease, and 71 young volunteers (mean age 18.9 yr) were tested binocularly on the Pelli-Robson Letter Contrast sensitivity chart and on the Regan High and Intermediate Contrast Charts over five luminance levels from 85 to 0.85 cd/m2. In addition, all volunteers were tested on the Bausch and Lomb Master Ortho-Rater at 245.5 cd/m2. 3. In the second experiment, an independent sample of subjects was used to evaluate performance on the Ortho-Rater as a function of luminance. The subjects were 73 older adults with self-reports of good ocular health (mean age = 71.0 yr), 46 older adults with self-reports of eye disease (mean age = 72.6 yr), and 64 young adults (mean age = 19.0 yr). 4. Results showed that all tests (Regan High and Intermediate Contrast, Pelli-Robson, and Ortho-Rater) yielded an age-group effect at all luminance levels. 5. All tests but the Regan High Contrast chart were able to discriminate the old subjects who reported healthy vs those reporting diseased eyes. The lack of discriminability of the Regan High Contrast chart as compared to the High Contrast Ortho-Rater was explained by suggesting that differences in task demands and/or potential "crowding effects" caused by the proximity of letters in the Regan chart may have masked differences between the two older groups. 6. The above experiments must be followed up with further research based on actual clinical evaluations of ocular health in order to enable us to compare findings for groups at different stages of ocular disease. This will allow us to determine if manipulation of luminance and contrast would serve as diagnostic and prognostic indicators.