A Comparative Study of Visual Acuity Tests

Abstract

The Snellen letter chart, preliterate E chart, Allen picture chart, and the HOTV test were compared in their ability to determine visual acuity and detect amblyopia. Sixty-four subjects were tested, with most of them performing three of the tests. Forty subjects had amblyopia. The Snellen letters and the E test had the most comparable acuities. The Allen picture chart provided better acuities than the other three tests, and the diagnosis of amblyopia was missed in over fifty percent of the cases with the Allen pictures. The HOTV test provided results very similar to the Snellen letter and the E tests. This method is preferred to the Allen picture chart for those who cannot read the Snellen letters or carry out the E test.

• visual acuity
• amblyopia
• Allen picture chart
• HOTV test