Abstract
Abstract: :
Purpose: To provide an almost complete description of the refractive status of the schoolchildren in a small city, Borba, in the central part of the Amazon rain forest. These children are primarilly of indigenous ancestry and the educational system in Borba is not as intensive or competitive as in developed countries. Methods: Ophthalmic examinations were performed on 723 of the children in the city schools between the ages of 6 and 14 years. This accounts for 93% of the schoolchildren in this age range. Cycloplegic retinoscopy was performed by a single ophthalmologist (LHC) on all subjects. Visual acuity, ocular motility tests and external inspection were also performed. Results: Mean equivalent spherical error was +0.60D ± 0.0.83D. The prevalence of myopic eyes </= –1.00D is just 1.94%, while for a criterion of </= –0.50D, the prevalence of myopic eyes is only 3.87%. The prevalence of moderate to high levels of hyperopia (>/= +2.00D) is also very low (1.94%). If the criterion includes low levels of hyperopia (>/= +1.00D), the prevalence of hyperopia soars to 26.6%. The prevalence of astigmtism and anisometropia at >/=1.00D criteria are low (7.8% and 2.3%) as would be expected in a primarily emmetropic sample. The axis of astigmatism is primarilly with–the–rule with a WTR prevalence of 69.3%. The mean equivalent sphere refractive error shifts very slightly away from hyperopia with increasing age (0.05D/year) and is slightly correlated with age (r = – 0.113, P = 0.003). Conclusions: Almost all of the children of the Borba school system are emmetropic. The prevalence of myopia is very low and there is almost no progression toward myopia with age. This study, along with our previous ARVO presentations on the refractive status of illiterate or semiliterate adults in the northwestern Brazilian Amazon and northeastern Brazil, links a lack of myopia with no education or with educational systems that do not demand intensive study by the students.
Keywords: refractive error development • myopia