Two new extensive studies find 1 in 4 preschoolers have vision problems that can be corrected if detected early, reports Charlene Laino of WebMD. The studies, Risk Factors for Hyperopia and Myopia in Preschool Children and Risk Factors for Astigmatism in Preschool Children, a collaboration of The Multi-Ethnic Pediatric Eye Disease and Baltimore Pediatric Eye Disease Studies, highlight the need for early vision testing, in particular for minority children (previous studies show only 1 in 20 preschool age children with vision problems).

Researchers examined the eyes of 9,970 children aged 6 months to 6 years from communities in Los Angeles and Baltimore; the participants were 44% African-American, 32% Hispanic, and 22% white, providing important data, previously lacking, on vision problems for minorities.

The studies' findings show that 4% of the children were nearsighted (myopic), 21% were farsighted (hyperopic), and 10% had astigmatism, a problem with the curvature of the cornea that leads to blurred vision. All of these problems are considered as "refractive errors" and can be corrected with glasses; however, even mild symptoms can pose a higher of risk of permanent vision loss if left untreated.

Rohit Varma, M.D., above, one of the lead researchers and professor of Ophthalmology and Preventive Medicine at theUniversity of Southern California's Keck School of Medicine, told WebMD, "If not corrected right early in life, these kids may have vision loss for life."  The studies identified risk factors that preschoolers could potentially be screened for: African-American and Hispanic children were more likely to be nearsighted or have astigmatism, whereas white or Hispanic children were more likely to be farsighted. Children who were nearsighted were also 4.6 times as likely to have astigmatism. Age was also a factor: children 6 to 35 months were more likely to be nearsighted compared with those 60 to 72 months of age. Babies 6-12 months were 3 times more likely to have astigmatism than older children ( 5-6 years old). These findings show that children can outgrow nearsightedness or astigmatism, but not farsightedness. Maternal smoking during pregnancy, although fairly low in prevalence, showed to be a risk factor: children were 1.46 times as likely to have astigmatism and more likely to be farsighted than for those whose mothers did not smoke.

Researchers also found more serious vision problems among preschoolers: 2% of the preschoolers had cross eyes (strabismus) and about 5% had lazy eye (amblyopia); both conditions can lead to permanent vision loss if not treated during early childhood. Risk factors included lack of health insurance and exposure to smoke during pregnancy.

Varma said the findings can be applied to U.S. preschoolers nationwide; however, one limitation is that fact the children were only assessed once, and further study is needed to see if they go on to develop vision loss and what treatments worked best.

The studies, funded by the National Institutes of Health, were published in October's  Ophthalmology and presented at the annual meeting of the American Academy of Ophthalmology.

Written for California's Children by Elizabeth J Carlyle.