Children who screen positive for amblyopia, reduced vision in one eye, before age 2 appear to have better visual outcomes than those whose vision problems are detected during screenings between ages 2 and 4, according to a new report.
Screening for amblyopia typically consists of visual acuity screening--where patients are asked to read letters on a chart--along with an examination to detect cataract, problems with eye alignment and other risk factors for the condition, according to background information in the article. Conventional visual acuity testing requires that children are old enough to cover one eye and read visual charts, whereas objective screening for risk factors and newer techniques involving taking photographs of the eye (photoscreening) can be performed in younger children.
Between 1996 and 2006, Alaska Blind Child Discovery--a cooperative, charitable research effort to offer vision screening to Alaskan children--used photoscreening to detect visual problems in 21,367 rural and urban Alaskan children through grade 2. Valerie G. Kirk and colleagues at Ophthalmic Associates, Anchorage, assessed the 94 children who screened positive before age 4 and were treated and followed for at least two years.
After amblyopia treatment, the 36 children who were screened before age 2 had better vision than the 58 who were screened between ages 2 and 4. "Despite similar levels of amblyogenic risk factors, the proportion of children failing to reach a visual acuity of 20/40 was significantly less among those screened before age 2 years (5 percent) than in those screened from ages older than 2 years and younger than 4 years (17 percent)," the authors write.
"Very early photoscreening yields better visual outcomes in amblyopia treatment compared with later photoscreening in preschool-aged children," they conclude.
Journal reference: Arch Ophthalmol. 2008;126:489-492.
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