The amblyopia treatment study visual acuity testing protocol

Arch Ophthalmol. 2001 Sep;119(9):1345-53. doi: 10.1001/archopht.119.9.1345.


Objective: To evaluate the reliability of a new visual acuity testing protocol for children using isolated surrounded HOTV optotypes.

Methods: After initial pilot testing and modification, the protocol was evaluated using the Baylor-Video Acuity Tester (BVAT) to present isolated surrounded HOTV optotypes. At 6 sites, the protocol was evaluated for testability in 178 children aged 2 to 7 years and for reliability in a subset of 88 children. Twenty-eight percent of the 178 children were classified as having amblyopia.

Results: Using the modified protocol, testability ranged from 24% in 2-year-olds to 96% in 5- to 7-year-olds. Test-retest reliability was high (r = 0.82), with 93% of retest scores within 0.1 logMAR unit of the initial test score. The 95% confidence interval for an acuity score was calculated to be the score +/-0.125 logMAR unit. For a change between 2 acuity scores, the 95% confidence interval was the difference +/-0.18 logMAR unit.

Conclusions: The visual acuity protocol had a high level of testability in 3- to 7-year-olds and excellent test-retest reliability. The protocol has been incorporated into the multicenter Amblyopia Treatment Study and has wide potential application for standardizing visual acuity testing in children.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amblyopia / physiopathology
  • Amblyopia / therapy*
  • Atropine / therapeutic use
  • Child
  • Child, Preschool
  • Humans
  • Mydriatics / therapeutic use
  • Reproducibility of Results
  • Sensory Deprivation
  • Vision Tests / methods*
  • Visual Acuity / physiology*


  • Mydriatics
  • Atropine