LAUSR

We would like to congratulate the authors for this valuable and interesting paper because vision disorders are acknowledged to be the leading cause of handicapping conditions in childhood. However, we would also like to comment on a few points. Zagreb Amblyopia Preschool Screening (ZAPS) study2 performed visual acuity (VA) testing both at near (40 cm) and distance (3 m), and this should be documented in Table 4,1 presented on page 5, as this is the essential contributor for the study outcomes. ZAPS study tested VA at near as well as at distance, due to following considerations: (1) hypermetropia is the most common refractive error in preschool children; hence, near VA should more reliably detect the presence of hypermetropia; (2) the greater the distance, the shorter the attention span is; and (3) to increase the accuracy of the test. The reason for high sensitivity (100%)2 and specificity (97%)2 levels as specified on page 71 could be attributed to the trained professional, 1 but is evidenced to be the result of using both near and distance VA testing. If performed alone, near VA testing would have a sensitivity of 74.5% and a specificity of 43.5%. 2 Sensitivity of the distance vision test using Lea Symbols in lines chart for distance, if tested alone, would reach 96.4%; however, specificity would be only 11.7%.2