Normative Data for Parameters of Accommodation in African Schoolchildren

SIGNIFICANCE: The reported interracial differences in normative data for parameters of accommodation call for investigating population-specific normative values. The study investigated and presents expected data for accommodative parameters among Ghanaian children. PURPOSE: This study aimed to determine expected values for parameters of accommodation among schoolchildren in the Central Region of Ghana. METHODS: This prospective cross-sectional study used a multistage cluster sampling approach. Normal participants were asymptomatic (Convergence Insufficiency Symptom Survey score ˂16), with unaided visual acuity or best-corrected visual acuity of 0.0 or better logMAR for each eye and having no ocular disease or no manifest strabismus. Normal participants underwent push-up and minus-lens-to-blur amplitude of accommodation tests, accuracy of accommodative response (using the monocular estimation method), and monocular and binocular accommodative facility testing. RESULTS: A total of 1261 normal participants within ages 11 to 17 years (mean, 14.75 ± 1.53 years) met the inclusion criteria. The mean normative data for the population include push-up amplitude of accommodation (14.04 ± 2.95 D), minus-lens-to-blur amplitude of accommodation (12.33 ± 2.55 D), and accuracy of accommodative response using the monocular estimation method (0.62 ± 0.22 D), monocular accommodative facility (9.80 ± 3.20 cycles per minute), and binocular accommodative facility (9.40 ± 3.30 cycles per minute). Age-predicted linear regression equations for the amplitude of accommodation are push-up amplitude of accommodation (16.74 - 0.18 × age in years) and minus-lens-to-blur amplitude of accommodation (15.7 - 0.23 × age in years). CONCLUSIONS: The study provides normative data for accommodative parameters that clinicians may use with Ghanaian populations of similar ages.