Abstract
Purpose: :
Refractive changes as children age are well documented and differences have been found in regard to ethnicity, rural versus urban dwelling, and increased close-up work. This study investigated refractive changes in 476 schoolchildren in Paraguay with three different ethnicities: Mennonite, indigenous (Macca), and mixed race.
Methods: :
Visual acuity without correction (logMAR), autorefraction with and without cycloplegia, and keratometry were conducted in children attending 3 schools catering to these groups that were present on the day of the examination. The autorefractor was calibrated to the manufacturer’s specifications prior to each use. Measurements were conducted by two ophthalmology residents trained by an experienced ophthalmologist.
Results: :
There were 190, 118, and 168 children of Mennonite (≤ 8 years: 74; 9-11 years: 53; ≥ 12 years: 63), indigenous (≤ 8 years: 36; 9-11 years: 32; ≥ 12 years: 51), and mixed race ethnicity (≤ 8 years: 34; 9-11 years: 97; ≥ 12 years: 37). Mean visual acuity (VA) without correction was better overall for Mennonites compared to indigenous or mixed race children (0.0375, 0.0682, and 0.0813 logMAR units, respectively; P < .00001). Mennonite children ≤ 8 years of age had a much better VA compared to indigenous or mixed race children (mean: 0.0425, 0.1294, and 0.1657 logMAR units, respectively; P = .000002), but the VA of indigenous and mixed race children improved in older children compared to Mennonite children. For autorefraction with cycloplegia, sphere values were consistently higher for Mennonites compared to indigenous or mixed race children (mean: 1.641, 1.415, and 1.540, respectively), lowest in regard to cylinder values (mean: 0.395, 0.549, and 0.820, respectively), and axis values (mean: 88.37, 93.34, 95.62. respectively). Multivariate analysis revealed a complex pattern suggesting more hyperopia for children under 11 years in Mennonites compared to indigenous and mixed race children.
Conclusions: :
Mennonites tended to show more hyperopia and other refractive changes compared to the other groups.
Keywords: refractive error development • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • emmetropization