Effects of yellow optical filters on contrast sensitivity function of albino patients.

BACKGROUND

Yellow ophthalmic filters are often prescribed for albino patients in an effort to enhance visual performance. The effects of a moderate- and a high-excitation purity yellow filter on the contrast sensitivity function (CSF) of ten albino patients were investigated. Hue discrimination loss induced by each filter was also evaluated.

METHODS

Three monocular CSF curves (best-corrected eye) were determined for each subject: one while viewing through a #3 Kodak Wratten filter, one through a #12 filter, and one used no filter. Panel D-15 color tests were administered to five albino patients viewing through each filter.

RESULTS

Using an analysis of variance (ANOVA) and a Student-Newman-Keuls Analysis, no statistical difference at the 0.05 levels of confidence was found between using no filter, the #3 filter, or the #12 filter CSF curves. A statistically significant blue-yellow hue confusion was induced by the #12 filter.

CONCLUSIONS

While neither filter was shown to enhance nor degrade the CSF among these subjects, a more extensive investigation may reveal that subtle but real contrast enhancement occurs with yellow filter use. High-purity filters should be avoided to minimize hue recognition losses.