Vision and Learning
Studies have shown that 80% of learning is visual. It only makes sense that if a child has
an untreated vision problem, he will have more difficulty learning than if he did not have that
Children should have a comprehensive eye examination prior to starting school in order to rule out any major problems. The doctors will evaluate the focusing system very thoroughly as it is critical in the learning process. They test how much focusing your child is able to do, how accurately your child focuses and how easily he can change his focus from far to near and near to far. They also evaluate how well your child is using his eye together as a team. In order to see clearly and singly, the eyes have to be well coordinated. This also effects eye movements and depth perception. Even if a child does not have an obvious eye turn, he may not be using his eyes together properly. This becomes a major issue when he is under stress or becomes fatigued.
The following are signs and symptoms of binocular vision problems: eyestrain, headaches, a head turn, or tilt, double vision, words moving or going in and out of focus, frequent loss of place when reading, avoidance near work and frequent eye rubbing.
Farsighted: Farsighted children have an easier time seeing far away objects than near-point details. It is caused by the eye being too short or the cornea/lens power being too weak (curvature/thickness). A farsighted child must exert extra focusing power in order to see clearly. He does this by using the focusing muscles that are normally just used to focus up-close. He must then focus even harder to see a near-point target. Farsightedness has been closely linked to developmental delays, difficulty with learning, and increased risk for developing a number of binocular vision disorders. These children almost always pass vision screenings. Farsightedness is best detected by doing a dilated (or cycloplegic) refraction.
Nearsighted: Nearsighted children cannot see far away. This is caused by the eye being too long or the cornea/lens power being too strong. Nearsightedness is easily detected because these are the children who fail vision screenings, can't see street signs, score boards, ect. Nearsightedness typically does not cause learning problems.
Astigmatism: This type of refractive error is generally caused by the cornea (the front surface of the eye being shaped more like a football than a basketball). This causes meridional defocus. For example, the vertical line of an "E" may be clear, while the horizontal lines are blurred. Small amounts of "with-the-rule" astigmatism are common. Larger amounts of "with-the-rule" and small amounts of "against-the-rule" and oblique astigmatism can cause problems with focusing, eye teaming skills, and can even cause amblyopia, (lazy eye).
Ambyopia: Amblyopia is also know as "lazy eye"; however, it does not necessarily mean that there is an eye turn. Amblyopia occurs when something prevents the vision from developing on one eye or both eyes. It is the leading cause of preventable blindness in the United States. The following are amblyogenic factors (causes of amblyopia):
*High or unequal refractive error (ie. Farsightedness, nearsightedness, or astigmatism)
*An eye turn (can be very small)
*An opacity (ie. A cataract or a scar)
*A ptosis (an eyelid droop)
Amblyopia is treatable. It is best treated at a young age. Outcomes are not as good when treatment is administered as a teenager or an adult.