If a child has difficulty reading, parents and teachers need to investigate many different causes. Usually a combination of problems lie at the root of a reading difficulty and all possible causes should be investigated.
One cause commonly overlooked is a child's vision. This is because the child appears to see well, does not complain about eye problems, has passed a school vision screening and has not had a comprehensive eye examination.
The ability to read needs the integration of various vision skills such as visual acuity, form perception, visual fixation, field of vision, accommodation, convergence and binocular fusion. Only one of these skills is checked by the typical school eye chart test. Limited eye examinations may cover only one or two and symptoms of reading- related vision disorders often are not noticeable to parent, teacher or child.
A comprehensive eye examination will cover these vision skills and is imperative for every child who is having difficulty reading.
Visual acuity simply means the ability to see objects clearly. It is commonly the only skill assessed in a school vision screening. The typical chart used in this test is designed to be seen at 20 feet and measures how well, or poorly, a child sees at that distance.
If a problem emerges with your child's vision in the screening, you should book a comprehensive eye examination with your optometrist immediately.
Form perception is the ability of a child to organize and recognize visual images as specific shapes. The shapes encountered by the child are remembered, defined and recalled when reading skills begin to develop.
Regular consultations with your optometrist will ensure your child has the necessary visual skills for successful classroom performance.
Visual fixation is the ability to aim the eyes accurately at a particular object.
Static fixation enables the child to focus on a stationary object when reading a word or studying a math problem, while saccadic fixation enables the child to move the eyes quickly and efficiently across a page when reading a line of print.
Pursuit fixation is the ability to follow a moving object with the eyes.
These complex operations depend on split second timing for the brain to process all information received and to focus on the stationary or moving object. Field of Vision
The field of vision is the entire area over which vision is possible. A child should be aware of objects in the peripheral vision (left and right and up and down extremities), as well as in the center of the field of vision.
Near central, or Para-central, vision is important for reading ability.
Accommodation enables one to adjust the focus of the eyes as the distance between oneself and the object changes. Children constantly use this skill in the classroom while shifting their attention between book and chalkboard for long periods of time. The ability to maintain focus on near objects for long periods is important for reading, writing and taking tests.
Convergence enables one to turn the two eyes toward each other while looking at a close object. Working at a school desk is an example where a child depends on this vision skill.
The term binocular fusion is used to describe the brain's ability to gather information separately from each eye and form a single, unified image. A child's eyes must align perfectly or discomfort, confusion, avoidance or blurred or double vision may result.
Should this happen, the brain can suppress or inhibit vision in one eye to avoid confusion. That eye may develop weaker visual acuity in the form of amblyopia or lazy eye.
Treating Reading-Related Vision Problems
The optometrist will examine the vision skills to determine the child's ability to use them together. If a vision problem is diagnosed, eyeglasses or vision therapy may be recommended.
Vision therapy has successfully treated reading-related vision problems. It involves a unique program of training procedures designed to help a particular child acquire or improve vision skills necessary for reading.
Treating Reading Problems
Reading problems usually have a variety of causes, so treatment needs to come from a number of quarters. Educators, psychologists, and eye care professionals must work together to solve each child's needs.
The role of the eye care practitioner is to help the child overcome vision problems impeding the ability to read. When this is achieved, the child can then respond to special education efforts aimed at treating the reading problem itself.