Abstract

While studying the aging visual system for the intended purpose of understanding age-related macular degeneration, we have employed a battery of tests that has included measures of 20-Hz flicker sensitivity on chromatic backgrounds. Unexpectedly, we found that more than 10% of people older than age 70 in a large control group had profound reductions of flicker sensitivity, more than 10 standard deviations from the mean norm, for at least one of the two background conditions used to measure flicker sensitivity. These people were more likely to be taking cardiovascular medication and/or have glaucotomous optic nerve head change than people without profound reductions. However, their intraocular pressures were within normal limits at the time of testing. Following these observations, we measure chromatic adaptation flicker tvi curves of young normal subjects, using 750-ms duration test stimuli. We found that on long wave length backgrounds flicker tvi slopes became great (~5) between 4.5 and 4.7 log td at 540 nm, but were near unity at 640 nm. The steep slopes coincided with the breakdown of effective M cone isolation. The results from young people suggest that profound losses of flicker sensitivity associated with low tension glaucoma could depend on spectrally opponent saturation. Preliminary results from people with low tension glaucoma are consistent with that possibility.

© 1989 Optical Society of America