Reading and writing skills begin to form in early childhood. By the time a child enters kindergarten, he or she is often expected to have some of the basic skills preceding literacy, such as starting to recognize letters, a growing vocabulary, and an ability to identify sounds that make up words.
But what if, unknown to the child's parents or teachers, he or she is farsighted — unable to focus on nearby objects, such as a book or computer screen? Can vision problems impact learning even before a child is able to read?
Even moderate uncorrected farsightedness in 4- and 5-year-old children significantly affects early literacy skills, according to the largest study of its kind, recently published in the journal Ophthalmology.
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The results suggest an untreated vision problem can delay a child's grade school readiness, says lead author Marjean Kulp of Ohio State University's College of Optometry. "The deficits we found in early literacy have been shown to be related to future ability to read and write."
The idea that early childhood vision problems are detrimental is controversial. Some doctors argue that children are good at adjusting, or "accommodating," their eyes to focus for sustained, close-up work. Other specialists contend that the effort to do so can result in eyestrain, headaches, and difficulty paying attention. Only one small study had previously examined the effect of farsightedness on reading in younger, preschool children.
The current study, funded by the National Eye Institute, assessed 492 children, who were 4 to 5 years old, in Boston, Philadelphia, and Columbus. Each child underwent a full eye examination. Next, an educational assessor, unaware of the child's vision status, conducted a preschool literacy test.
Children with uncorrected farsightedness did significantly worse on the literacy test than children with normal vision, and the negative effects were greater in kids with higher amounts of farsightedness.
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Many states do require vision screening for young children, but typically not until kindergarten. Massachusetts, for example, requires children pass a vision-screening test within 12 months of entering kindergarten.
Still, Kulp is hesitant to recommend correcting all farsightedness in small children. "There is variation in terms of what is recommended for moderate farsightedness," she says. Some doctors won't prescribe glasses if a child is young, believing the corrective lenses could interfere with the child's ability to "grow out of" being farsighted. There are reported cases where mild farsightedness seems to improve with time, but that typically occurs at a younger age, Kulp says, and there is no convincing evidence of it happening in preschoolers.
In the end, it can't hurt to have a preschooler's vision checked if you think they are having difficulty, but another study will need to be done to assess whether corrective lenses have a positive impact on early literacy skills. "That's a study we're hoping to do," says Kulp. "It's in the planning stages."