Evaluation of Visual Acuity and Myopia Prevalence in Greek and Bulgarian School Children

Abstract

Purpose: : To assess visual acuity (VA) using the habitual refractive correction and estimate the prevalence of refractive error in primary and secondary school children in a Greek and Bulgaria.

Methods: : A cohort of 926 children, aged 10 to 15 years, from four randomly-selected schools in a Greek (Heraklion) and a Bulgarian (Stara Zagora) city of similar population size (~180.000) was examined. 616 were Greek (age 12.7±1.5 yrs) and 310 Bulgarian (age: 12.5±1.4 yrs), while 453 were in primary (age: 11.4± 0.6 yrs) and 477 in secondary education (age: 13.9±0.7 yrs). VA was assessed with the habitual refractive correction, using the UoC European-wide logMAR charts (Plainis et al., 2007). Sphero-cylidrical refractive error was measured using an auto-refractometer (Potec RK, Essilor).

Results: : Analysis showed that 23.9% of Greek vs. 8.7% of Bulgarian children wore spectacles at school. The percentage of children with minimal visual impairment (decimal VA < 0.8) in at least one eye was 31.7% (95% CI 28.0%-35.3%) for Greek compared to 21.9% (95% CI 17.3%-26.5%) for Bulgarian children. When the impairment criterion was set to VA < 0.5 (mild impairment), the corresponding values were 11.4% (95% CI 8.9%-13.9%) for Greek and 4.8% (95% CI 2.5%-7.2%) for Bulgarian students. However, while 52.8% of Greek children with VA 0.75 D and decimal VA < 0.8. Myopia prevalence was also found to differ between primary (24.6%) and secondary (36.5%) school children in each country.

Conclusions: : A significant number of children in both countries attend school lessons with minimal VA impairment. The increased values of myopia prevalence in Greek compared to Bulgarian school children may arise from socio-economic differences. The difference in myopia prevalence in the two age groups highlights the rapid progress of myopia in school ages.

Keywords: visual acuity • clinical (human) or epidemiologic studies: prevalence/incidence • myopia