Effect of age using Lea Symbols or HOTV for preschool vision screening.
OBJECTIVE
To compare the effectiveness of the Lea Symbols and the HOTV distance visual acuity tests, presented monocularly in linear, crowded formats at 3 m, as vision screening tests to identify 3- to 5-year-old children in need of eye care.


METHODS
Subjects were 1,142 3- to 5-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 visual acuity. 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 of age 3 were tested with 10/100, 10/32, 10/25, and 10/20 optotypes whereas those who were 4 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 3-year-old group (mean age, 45.3 months), where the sensitivity for detection of > or =1 targeted conditions was 61% for the Lea Symbols and was 46% for the HOTV letters (difference 15%, 95% confidence interval: -0.01 to 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 to 0.49). However, neither these differences nor any of the other age group sensitivity differences were statistically significant. For the 3-year-old children, the pass/fail criterion was one line larger for the HOTV letters than for the Lea Symbols.


CONCLUSIONS
Most children completed both tests. Although the 3-year-old children achieved better acuity scores with the Lea Symbols test, there were no statistically significant differences in sensitivity between tests for any age group.
D000367:Age Factors; D000375:Aging; D002675:Child, Preschool; D004215:Distance Perception; D006801:Humans; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D015351:Vision Screening / Q000379:methods*; D014787:Vision Tests / Q000295:instrumentation* / Q000592:standards*; D014792:Visual Acuity