Refractive error study in young subjects:results from a rural area in Paraguay

摘要

AIM:To evaluate the distribution of refractive error in young subjects in a rural area of Paraguay in the context of an international cooperation campaign for the prevention of blindness. METHODS:A sample of 1466 young subjects(ranging from 3 to 22 years old),with a mean age of 11.21±3.63 years old,were examined to assess their distance visual acuity(VA)and refractive error. The first screening examination performed by trained volunteers,included visual acuity testing,autokeratometry and non-cycloplegic autorefraction. Inclusion criteria for a second complete cycloplegic eye examination by an optometrist were VA <20/25(0.10 log MAR or 0.8 decimal)and/or corneal astigmatism ≥1.50 D. RESULTS:An uncorrected distance VA of 0 log MAR(1.0decimal)was found in 89.2% of children. VA <20/25 and/or corneal astigmatism ≥1.50 D was found in 3.9% of children(n=57),with a prevalence of hyperopia of 5.2%(0.2%of the total)in this specific group. Furthermore,myopia(spherical equivalent ≤-0.5 D)was found in 37.7% of the refracted children(0.5% of the total). The prevalence of refractive astigmatism(cylinder ≤-1.50 D)was 15.8%(0.6% of the total). Visual impairment(VI)(0.05≤VA≤0.3)was found in 12/114(0.4%)of the refracted eyes. Main causes for VI were refractive error(58%),retinal problems(17%,2/12),albinism(17%,2/12)and unknown(8%,1/12).CONCLUSION:A low prevalence of refractive error has been found in this rural area of Paraguay,with higher prevalence of myopia than of hyperopia.