The effect of decreased visual acuity on clinical color vision testing.

Abstract

Evaluate the effect of visual acuity on color vision testing. University based clinical experimental study. Right eyes of 12 healthy subjects were fogged with plus lenses to logMAR 1.88 and assessed with D-15 panel, Ishihara, and Hardy-Rand-Rittler (HRR) plates. Subjects were tested at lesser degrees of fogging, 0.1 logMAR intervals. The acuity at which 5% of the population tests abnormally was estimated as follows. The average acuity at which a 10% reduction in correct responses occurred was determined. From this, two standard deviations were subtracted. Examination devices were compared using repeated measures analysis of variance. Color vision testing did not significantly differ from baseline up to logMAR 1.40 (D-15 panel), 1.10 (HRR plates), and 0.72 (Ishihara plates). Testing devices were significantly different (P < .005). Color vision testing is accurate up to logMAR 1.40 (20/501) with D-15 panel, 1.10 (20/252) with HRR plates, and 0.72 (20/106) with Ishihara plates.