title: Differences in visual acuity between the eyes: determination of normal limits in a clinical population.
abstract: We determined the difference in visual acuity between the right and left eyes of patients and also determined the maximal level of acuity expected in a group of visually normal individuals. Visual acuity was measured in the right and left eyes of 72 subjects aged from 16 to 67 years using Bailey-Lovie type charts. The chart was read until fewer than three letters were read on a line and acuities were based on each letter correct contributing -0.02 to the overall score. For 12 of these subjects, visual acuity was measured a further four times. Average visual acuities for right and left eyes were -0.137 and -0.126log MAR, respectively. The signed visual acuity difference was normally distributed and had a standard deviation of 0.050log MAR. The mean visual acuity difference for the 12 subjects for whom the measures were repeated was 0.033log MAR (SD of the signed visual acuity difference: 0.049log MAR). We conclude that if a patient has a difference in visual acuity between the two eyes of more than 5 letters on a Bailey-Lovie style chart, further investigation is indicated.
authors.affiliation: Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom.
authors.forename: B
authors.initials: B
authors.lastname: Brown
authors.forename: M K
authors.initials: MK
authors.lastname: Yap
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D014787:Vision Tests; D015349:Vision, Monocular; D014792:Visual Acuity