Prevalence of refractive errors among school children in Northeastern Iran.
OBJECTIVE
To determine the prevalence of refractive errors among schoolchildren in Northeastern Iran by age and gender.


METHODS
Using multistage random cluster sampling, 2020 schoolchildren 6-17 years of age were selected for this cross-sectional study. The participants totalled 1551 (response rate 76.8%) elementary and junior high school children (41.5% boys and 58.5% girls) from the northeast of Iran. Cycloplegic autorefraction was used to determine refractive error. Myopia was defined as a spherical equivalent (SE) of -0.50 dioptre (D) or worse, hyperopia as a SE of +2.00 D or more, and astigmatism as cylinder equal to or worse than -0.75 D.


RESULTS
The prevalence of uncorrected, habitual and optimal visual acuity of 6/12 (0.30 logMAR) or worse in the better eye was 2.2%, 1.0%, and 0.2% respectively. The prevalence rates of myopia, hyperopia and astigmatism were 4.3% (95%CI: 3.3-5.3), 5.4% (95%CI: 4.3-6.5) and 11.5% (95%CI: 9.9-13.1) respectively and were not related to gender. The prevalence of myopia and against-the-rule astigmatism increased significantly with age (p < 0.0001). The prevalence of hyperopia significantly decreased with age (p < 0.0001).


CONCLUSIONS
The prevalence of myopia in schoolchildren in Northeastern Iran is considerably lower than that of East Asian populations, but similar to many other populations, including South Africa, Chile and other countries of the Middle East. Whilst comparisons with other studies show that the prevalence of hyperopia and astigmatism in Northeastern Iran is higher than that of some countries, it is lower compared with others.
Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
Farhad
F
Rezvan
Mehdi
M
Khabazkhoob
Akbar
A
Fotouhi
Hassan
H
Hashemi
Hadi
H
Ostadimoghaddam
Javad
J
Heravian
Elham
E
Azizi
Abbas Azimi
AA
Khorasani
Abbas Ali
AA
Yekta
D000293:Adolescent; D017677:Age Distribution; D001251:Astigmatism / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology*; D007492:Iran / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D009216:Myopia / Q000453:epidemiology*; D015995:Prevalence; D017678:Sex Distribution