Feb. 13 (HealthDay News) -- Preschoolers with poor vision significantly improved their test scores within six weeks of consistently wearing prescription glasses, a new study shows.

"It has been theorized that when young children have early vision problems that are undiagnosed and uncorrected, their development and performance in school are impacted," Stuart I. Brown, chairman of ophthalmology and director of the Shiley Eye Center University of California, San Diego, School of Medicine, said in a prepared statement. "This study shows that children with vision impairment do perform below the norm in visual-motor coordination tests, and that they catch up quickly once they are given corrective [lenses]."

The study, published in the February issue of the Archives of Ophthalmology, followed 70 children, aged 3 to 5, about half of whom had normal vision, and half were diagnosed with ametropia -- abnormal refractive eye conditions leading to poor vision, such as astigmatism. The children took two standardized tests that relate directly to future school performance: the Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R).

Before being given glasses, the vision-impaired children scored significantly lower on both tests, demonstrating reduced ability of the brain to coordinate the eyes with the hands, the researchers said.

That changed after the vision-impaired children were provided with prescription glasses and monitored with the assistance of their families over six weeks to ensure that they wore their glasses consistently.

Upon retesting, the VMI scores of the children with vision problems were at the same level as the scores of the children with normal eyesight. The WPPSI-R scores did not show the same dramatic improvement, but the researchers speculated that the test might not be as sensitive to changes in visual-motor integration skills tested by the VMI tool. The researchers are following the children to test whether the WPPSI-R scores change further over time.

"Amazingly, this is the first controlled study of preschool children to show the cognitive disadvantage preschool children have when they are farsighted and/or have astigmatism, as well as to show the benefit of early intervention with glasses," study co-author Barbara Brody, director of the Center for Community Ophthalmology at the Shiley Eye Center, said in a prepared statement.

SOURCE: University of California, San Diego, School of Medicine, news release, Feb. 11, 2008