Preschool visual acuity screening with HOTV and Lea symbols: testability and between-test agreement

Abstract

Purpose: To compare the performance of 3- to 5-year-old children on visual acuity screening with HOTV letters vs. Lea symbols as optotypes.

Methods: Subjects included 1253 Head Start children who were aged either 3 or 4 years on September 1 of the school year of testing. The sample over-represented children who had not passed a Head Start screening. Binocular pretesting at 1 m demonstrated the child's ability to identify the optotypes verbally or by matching optotypes on a lap card. Acuity was tested monocularly at 3 m using crowded single lines of optotypes. Lines tested were based on age at the beginning of the school year (September 1) with 3-year-old children tested with lines 10/100, 10/32, 10/25, and 10/20 and 4-year-old children tested with 10/100, 10/25, 10/20, and 10/16.

Results: Overall, 99% of children were able to complete the binocular pretest for each test successfully, and there was no difference between the tests (p = 0.83). Children's ability to complete the pretest increased slightly with age. HOTV test scores were slightly worse than Lea symbols test scores (p = 0.047), primarily because more children were unable to pass the monocular 10/100 card for the HOTV test than for the Lea symbols test (2.6% vs. 1.3%). The percentage of identical results on HOTV vs. Lea overall was 67.3% and increased significantly with age. When the results were different, 3-year-old children, but not 4- and 5-year-old children, tended to have worse results on the HOTV letter test.

Conclusions: The vision of nearly all 3- to 5-year-old children can be screened using either HOTV letters or Lea symbols. HOTV letters may be slightly more difficult than Lea symbols for 3- to 5-year-old children, with the largest difference between acuity results on the two tests occurring in 3-year-old children.