The Effect of Test Method on Visual Acuity in School Children Aged 4-5.

Purpose: This study compared two different methods of testing visual acuity (VA) in children aged 4-5 years (The UK's school vision screening target age). A conventional vision test method was compared to a reversed presentation order of logMAR, where letters are presented in ascending size order up to vision threshold. Threshold VA, test duration and concentration were compared, to assess the most accurate and efficient method of VA testing in this age group, to determine the most clinically and cost-effective method for vision screening. Methods: Thirty-four participants completed the study (15 males, 19 females, age range 53-65 months, mean age 59 months' ±3.7 months). VA was measured in logMAR. Keeler Crowded logMAR screening plates determined the starting line on the vision chart to ensure the initial optotype size was either seen or not seen for the conventional and reversed test methods respectively. Test duration was measured in seconds and a concentration score was given by the examiner. Results: The median VA was 0.17 logMAR for each test method. There was no significant difference in the VA outcomes between each test method (p = 0.46). The reversed method was significantly quicker to complete, with a median reduction in test duration of 28 seconds (p = 0.002). There was no difference in concentration levels between the test methods. Conclusion: Both test methods gave the same VA threshold, and are therefore comparable. The reversed method was significantly quicker to complete which could benefit school vision screening services and busy clinical contexts.