As part of routine school health assessments, children's eyesight is commonly tested in school vision screenings. However, passing a school vision screening does not guarantee the absence of a vision problem. These screenings are typically limited in scope to reading letters on a distance eye chart and are not intended to replace a comprehensive vision evaluation that can detect vision based learning problems. In fact, many times these important vision disorders routinely evade detection.
It is estimated that 35-40% of all children with learning disabilities have visual problems. Specifically, at least 20% of individuals with learning disabilities have been found to have prominent visual information processing problems, and 15-20% of them have problems with visual efficiency skills.
Without efficient visual skills the act of reading can be very frustrating. To the child with a vision based learning problem - often called a "hidden disability" - these frustrations can spill over into behaviors that can present themselves in a fashion similar to attention deficit disorders such as ADD/ADHD, or reading problems such as dyslexia.
Prevention of vision problems and their consequences require timely detection. The College of Optometrists in Vision Development (COVD) recommends that all children receive a thorough professional eye and vision examination, particularly one that includes a comprehensive assessment of visual information processing and binocular function. A child should have a developmental vision assessment at age 3 and again at age 5 prior to entering school to monitor vision development. School vision screening alone are not sufficient for investigation of visual function for school-aged children.