A colleague in the United States put together this short list of facts about learning and vision. I have repeated some of it here with some modifications:
Most people think that if a person’s visual acuity is 20/20, their vision is ‘normal’ or ‘perfect’, but nothing could be further from the truth.
Visual acuity is the measure of the clarity of a person’s vision and is tested by having the person read a line of letters on an eye chart. This test does not require the same types of vision skills (focusing and eye movement control) that reading does, so it cannot be used to determine whether a child has the visual skills necessary to read and succeed in school.
While clear vision is important, it is only one of many visual skills required to be able to read and learn.
> 75-90% of classroom learning comes through the visual system in today’s classrooms.
> 80% of children who are reading disabled, including those with dyslexia, have vision problems that can be resolved.
> 25% of ALL children have vision problems significant enough to affect their performance in school.
> 95% of first grade non-readers have significant vision problems. They have 2.5 times more visual problems than high-achieving first-graders.
> In one study, 70% of juvenile delinquents had a significant vision problem.
> In one California funded study, recidivism (repeat offenders) reduced from 45% to 16% when wards received on-site therapy for troubled vision.
> When a group of illiterate adults were vision screened, there was a 74% failure rate.
> School vision screenings, such as those that rely on eye charts, detect only 20#0% of vision problems, and many of those are actually advantages for learning (like nearsightedness).
> Only 13% of parents with children under 2 years of age have taken their baby for a functional vision assessment, yet 1 of 10 children are at risk of a having an undiagnosed vision problem, with the number rising as school age approaches.
> Kentucky implemented a requirement for vision exams as children enter Grade 1. By this alone, achievement statewide rose 5-7% in the following 7 years.