Vision screening in schoolchildren: two years results.
OBJECTIVE
To assess the prevalence of visual impairment and ocular abnormalities among schoolchildren in Chiang Mai.


METHODS
A community-based survey.


METHODS
The vision screening project was conducted from June 2000 to March 2002. Students in grade I in the Chiang Mai municipal area were examined for visual acuity (VA), color vision, ocular alignment, anterior segment and fundus. Subjective refraction was done in students with subnormal vision (VA 20/30 or less). Referral to the hospital for further evaluation and treatment was made for students with strabismus, amblyopia and other ocular abnormalities.


RESULTS
A total of 3,431 and 3,467 students were enrolled in 2000 and 2001, respectively. The prevalence of normal vision (VA 20/20), VA 20/30 or better in at least one eye and 20/40 or less in at least one eye were similar in both years (87%, 5.7%, 7.3% and 85%, 6.4%, 8.7%, respectively). There was no statistically significant difference in visual acuity among boys and girls in either year (p = 0.6 and p = 0.2). Prevalence of abnormal color vision was 4.2%. Other causes of visual impairment in both years included strabismus (1.5% and 6.2%), amblyopia (1.1% and 1.4%) and some congenital abnormalities. Most cases of amblyopia were due to uncorrected refractive errors.


CONCLUSIONS
The authors found that over 10% of school-aged children had subnormal vision. The important causes of visual deterioration came from refractive errors, strabismus and amblyopia. The authors concluded that vision screening is a cost-effective way of reducing visual morbidity from preventable visual impairment, which is a tragedy that cannot be ignored.
Department of Ophthalmology, Chiang Mai University, Thailand. ntananu@mail.med.cmu.ac.th
Napaporn
N
Tananuvat
Anita
A
Manassakorn
Apaporn
A
Worapong
Jarassri
J
Kupat
Jenjitr
J
Chuwuttayakorn
Sopa
S
Wattananikorn
D000550:Amblyopia / Q000453:epidemiology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012029:Refraction, Ocular; D013285:Strabismus / Q000453:epidemiology; D013785:Thailand / Q000453:epidemiology; D014786:Vision Disorders / Q000453:epidemiology*; D015351:Vision Screening; D015354:Vision, Low / Q000453:epidemiology; D014792:Visual Acuity