Normative Data for Nonstrabismic Binocular Vision Parameters in African Schoolchildren

Supplemental digital content is available in the text. SIGNIFICANCE With reported population differences in parameters of nonstrabismic binocular vision, the present study investigated and reports normative data among a sample of African children. PURPOSE This study aimed to determine expected binocular visual function data among schoolchildren in the Central Region of Ghana. METHODS The study used a prospective cross‐sectional design and used a multistage cluster sampling approach. Eligible normal participants selected through the administration of Convergence Insufficiency Symptom Survey questionnaire (score <16) and preliminary vision screening underwent comprehensive binocular vision testing. Only data for participants who expressed no difficulty with the specific procedures were analyzed. RESULTS A total of 1261 normal participants (11 to 17 years [mean, 14.75 ± 1.530 years]) were selected for comprehensive binocular vision testing in the normative data study. The means with ±1 standard deviation for normative data for the nonstrabismic binocular vision parameters include the following: accommodative target near point of convergence (NPC) break (6.10 ± 1.67 cm), NPC recovery (8.17 ± 1.67 cm), fixation light with red‐green anaglyph (RG NPC) break (8.51 ± 2.43 cm), RG NPC recovery (10.95 ± 2.60 cm), cover test distance phoria (0.12 ± 0.79 exophoria), cover test near phoria (2.1 ± 2.3 exophoria), modified Thorington test near phoria (1.9 ± 2.5 exophoria), negative relative accommodation (+2.54 ± 0.75 D), positive relative accommodation (−2.58 ± 0.81 D), and the accommodative convergence over accommodation ratio (2.80 ± 1.07:1). Age (in years)‐predicted normal linear regression equations for NPC break (5.13 + 0.07 × age), RG NPC break (10.00 − 0.10 × age), RG NPC recovery (12.83 − 0.13 × age), positive relative accommodation (2.05 + 0.04 × age), and the gradient accommodative convergence over accommodation ratio (3.97 − 0.08 × age) serve as a guide. CONCLUSIONS The study provides expected data that optometrists may use with similar aged Black African populations.