Refractive errors and visual impairment among children and adolescents in southernmost China

Refractive errors and visual impairment in southernmost China have not been reported previously. We aim to investigate and determine the age-specific prevalence of myopia, hyperopia, astigmatism, and visual impairment based on a large population cross-sectional study in Hainan area of southernmost tropical province in China.

A population-based sample of 31,524 children aged 6-15 years from Hainan was assessed. Non-cycloplegic autorefraction and visual acuity (VA) analyses were performed on all participants and a subgroup of participants undergoing cycloplegia.

Of all participants, 23.0% presented uncorrected VA (UCVA) was worse than 20/40 in worse eye, 6.0% presented mild presenting visual acuity impairment (PVAI), 7.0% presented moderate PVAI, 0.2% presented severe PVAI in the better eye, and 46.9% presented abnormal UCVA [worse than 20/25 (≥ 6, < 8 years old) and worse than 20/20 (≥ 8 years and older)] at least in one eye. The overall prevalence of myopia [spherical equivalent (SE) ≤  - 0.50 D] and high myopia (SE ≤  - 6.00 D) were 46.0%, 1.0% respectively. Hyperopia [SE ≥  + 1.00 D (≥ 7 years old) and SE ≥  + 2.00 D (≥ 6, < 7 years old)] and significant hyperopia (SE ≥  + 3.00 D) were 4.2 and 0.6%, respectively. Astigmatism [cylinder ≥ 1.00 D (≥ 7 years old) and ≥ 1.75 D (≥ 6, < 7 years old)] was found in 31.9%.

Myopia was the most common refractive error in southernmost province in China (Hainan). Its prevalence increased with age, while hyperopia prevalence showed a decreasing trend. However, myopia, especially high myopia prevalence was much lower than in other urban regions across China.