Validation of a self-report inventory for the measurement of visual acuity.

Abstract

Previous attempts to assess visual acuity via self-report survey items have shown low sensitivity. This may be due to use of dichotomous response formats, too few items, and reliance upon face valid, rather than laboratory-validated items. On the basis of a preliminary sample of 164 individuals, we developed a self-report inventory, suitable for group testing or survey administration. The inventory was then validated against laboratory measures of acuity in a separate sample of 570 subjects. The resulting, brief, ten-item scale was shown to be a reliable and valid predictor of visual acuity. Conversion tables were developed which allow scale totals to be used to predict Snellen acuity. For 91% of the sample, the inventory predicts objectively measured acuity within plus or minus one Snellen line. A copy of the inventory and scoring procedure is appended to this report.