Abstract

“Quality and quantity of light are significant considerations in the care of partially sighted individuals” (Rosenberg, 1984). It is common clinical practice to stress adequate lighting for low vision patients - particularly to enhance the use of optical aids for reading. Louise Sloan (1977) recommended that high intensity lamps be used as auxiliary reading aids for low vision patients with macular disease; very bright task lighting allowed some patients with macular disease to read standard text with less magnification. Bullimore and Bailey (1995) reported that subjects with age-related maculopathy were more likely to be affected by luminance in a word reading task than subjects with normal vision. Comelissen and colleagues stress the importance of assessing illumination by subjective and objective measures in order to optimize reading performance for low vision readers. Brown and co-workers reported in 1984 that patients with age-related maculopathy and moderately reduced Snellen visual acuity had profound decreases in acuity at low luminance (0.26 and 0.75 cd/m²). Each of these studies suggests the importance of luminance effects on reading by low vision patients, each also reports considerable variability among patients even when the patients share the same diagnosis. The question remains - how are low vision patients with central visual field loss (CFL) different from subjects with normal vision in their responses to changes in luminance? We report here an investigation of the effects of luminance on Rapid Serial Visual Presentation (RSVP) reading, and visual acuity from video-based text displays.

© 2000 Optical Society of America