As a child who had print disabilities and did in fact need glasses, I can attest that I'm not surprised about this. While my own vision was good till about 6th grade, then I was involved in an accident that detached a retina and started deteriorating, giving me conflicting vision between my eyes, when in 7th grade led to failing spelling. Today, while the conflict is gone, I still use larger print as it is so much easier to read (than a size 10 or 12 font), which is a great thing about ebooks. I also now teach my own students about how they should check their students for things like both eyes tracking and convergence just by watching a student's eyes.
Just 15 states require that preschool students be screened for vision problems, according to a report released today by the National Center for Children's Vision and Eye Health. Research has shown that vision problems can affect students' academic performance.
National Public Radio (4/4)