Evaluation of visual function in preschool-age children using a vision screening protocol

Tsukasa Satou, Yoshiaki Takahashi, Misae Ito, Hiroshi Mochizuki, Takahiro Niida Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Otawara, Tochigi, Japan Purpose: To evaluate the relationship between uncorrected visual acuity and refraction and binocular function using a vision screening protocol. Methods: In total, 760 children (3–6 years old) who were enrolled in 4 nursery schools in Otawara, Japan, were recruited; a total of 1,520 eyes were examined. We assessed uncorrected near visual acuity, manifest refraction, stereopsis, and eye position. Subjects were divided into 4 subgroups according to the lowest uncorrected near visual acuity value compared between the 2 eyes: group 1 (visual acuity [VA] ≤0.00 [logarithm of the minimum angle of resolution]), group 2 (VA 0.15–0.05), group 3 (VA 0.52–0.22), and group 4 (VA >0.52). These parameters were compared among the groups. Results: The sample number of each of the 4 sub-groups was as follows: group 1, 608; group 2, 114; group 3, 27; and group 4, 11. The median spherical equivalent values were -1.13 diopter (D) in group 1 and -1.00 in group 2, which were more myopic than group 4. Median cylindrical power in group 1 was 0.25 D, and was the lowest among all groups. In group 1, median anisometropia was 0.38 D and median corneal astigmatism value was 1.13 D; both values were lowest in group 1. With regard to binocular function, 89.6% of the subjects in group 1 had 60 arcseconds or better in near stereopsis and 98.8% had no detectable strabismus, which were significantly different from the findings in the other groups. The percentage of subjects in group 1 who had 80 arcseconds or worse in near stereopsis was 10.4%. In contrast, 90.9% of the subjects in group 4 had 80 arcseconds or worse in near stereopsis, and 18.2% had intermittent or manifest strabismus. Conclusion: We suggest that examination of refraction and stereopsis in preschool-age children undergoing vision screening is an important supplement to visual acuity testing. Keywords: vision screening, preschool children, refraction, binocular function, non-cycloplegic, hand held autorefracto