Normal Monocular and Binocular Visual Acuity in Seven-Year-Old Children

详细

The purpose of this study was to obtain age-specific normative data for visual acuity (VA) in sevenyear- old children. The sample included a total of 127 healthy children (mean age 7.53 ± 0.025 years) without ophthalmic disorders. Monocular and binocular VAs were determined to the threshold level at two distances, 5 m and 0.5 m, using eye charts with eight intermediate levels between 1.0 and 2.4 (in the decimal notation system) with widely spaced tumbling Snellen’s E optotypes randomly distributed in four orientations. Since the optotypes were located in lines at intervals that were twice as large as the size of the optotype itself, they could be considered as single stimuli. The normal monocular and binocular VAs were 1.279 ± 0.025 and 1.491 ± 0.028 at 5 m and 1.256 ± 0.024 and 1.388 ± 0.025 m at 0.5 m, respectively (mean ± standard error of mean). Interocular differences in VA are also discussed. Our findings show that the normal VA in seven-yearold children is higher than the clinically accepted norm of 1.0; therefore, VA measurement to the threshold level is necessary for earlier visual disorders to be detected.