Snellen visual acuity was measured in 106 patients ranging in age from 20 to 88 years in routine examinations in the general refraction clinic with two kinds of charts: the standard chart using black letters on a white background and a reversed-contrast display featuring white letters on a black background. The overall ratio of the white-on-black to the black-on-white Snellen fractions was 1.043. A scattergram relating this ratio to patient age revealed that the older the patient, the more the visual acuity was improved by switching to the reversed-contrast chart, with a regression line slope of 0.5 ± 0.10. Impairment of the eye’s optics, in particular by intraocular scatter causing a widening and flattening of the eye’s point-spread function, explains these findings and suggests prognostic and therapeutic value of reversing the contrast polarity of displays.