Effect of Age Using Lea Symbols or HOTV for Preschool Vision Screening

Purpose—To compare the effectiveness of the Lea Symbols and the HOTV distance visual acuity (VA) tests, presented monocularly in linear, crowded formats at 3 m, as vision screening tests to identify three- to five-year-old children in need of eye care. Methods—Subjects were 1,142 three- to five-year-old Head Start children who completed a comprehensive eye examination, used to determine if the child had one or more targeted conditions: amblyopia, strabismus, significant refractive error, or unexplained reduced VA. Each child was tested on both tests by masked examiners, with test order determined randomly. The optotype sizes administered were age-based according to the child’s age at school entry on September 1. Children age three were tested with 10/100, 10/32, 10/25, and 10/20 optotypes while those who were four were tested with 10/100, 10/25, 10/20, and 10/16 optotypes. Results—Most children (>95%) completed both tests, with no statistically significant differences. Pass/fail cut-offs were set to yield specificities as close as possible to 90%. The largest sensitivity differences observed were in the three-year-old group (mean age 45.3 months), where the sensitivity for detection of ≥1 targeted conditions was 61% for the Lea Symbols and was 46% for the HOTV letters (difference 15%, 95% confidence interval {−0.01, 0.30}) and the sensitivity for detection of Group 1 conditions was 83% for the Lea Symbols and 57% for the HOTV letters (difference 26%, 95% confidence interval {−0.01, 0.49}). However, neither these differences nor any of the other age group sensitivity differences were statistically significant. For the three-year-olds, the pass/fail criterion was one line larger for the HOTV letters than for the Lea Symbols.