Abstract
Purpose: :
There is a paucity of data on the prevalence of refractive error in the UK, especially in children. The Northern Ireland Eye Study, along with its sister study the Aston Eye Study, are the first population based surveys of children using both random cluster sampling and cycloplegic autorefraction to quantify levels of refractive error in the UK.
Methods: :
• Children aged 6-7 years and 12-13 years were recruited from a stratified random sample of primary and post-primary schools, representative of the urban/rural population of Northern Ireland as a whole.• Participants were tested at school with consent from both child and parent/guardian. Measurements of LogMAR vision, visual acuity, oculomotor balance, biometry and cycloplegic autorefraction were taken.• Right eye spherical equivalent results were used to define myopia (≤-0.50DS), hyperopia (≥+2.00DS) and astigmatism (≥1.00DC), with anisometropia defined as an interocular difference ≥1.00DS.
Results: :
Of those invited, 57% (n=399) of 6-7-year-olds and 60% (n=669) of 12-13-year-olds participated. Data are presented for white participants only (99%). The prevalence of myopia was 2% (95% CIs 0.5-3.6) in 6-7-year-olds and 15% (95% CIs 10.7-19.3) in 12-13-year-olds. The prevalence of hyperopia was 22% (95% CIs 16.1-28.3) in 6-7-year-olds and 12% (95% CIs 8.0-15.6) in 12-13-year-olds. Levels of astigmatism (21.4%, 95% CIs 17.5-25.2) and anisometropia (9.1%, 95% CIs 8.8-9.4) remained relatively stable between 6-7 and 12-13 years.
Conclusions: :
This study shows stark differences in the prevalence of myopia from early to late childhood. The prevalence of myopia at 12-13 years suggests that 1 in 7 children are in need of optical correction at secondary school age. The prevalence of myopia, hyperopia and astigmatism are much higher in children from Northern Ireland, compared to other studies of white children of similar age from other countries.
Keywords: myopia • hyperopia • astigmatism