Summer is coming to a close and that means school is back in session. For some schoolchildren, this means getting an eye exam. Many parents wonder why eye exams are required before you enter kindergarten or certain grades when they do not notice any issues with their children’s eyes. Here are a few common issues we typically encounter that is not always noticeable:
Amblyopia (Lazy Eye)
Lazy eye, or amblyopia, is the loss or lack of development of central vision in one eye that is unrelated to any eye health problem and is not correctable with lenses. It can occur when a person does not use both eyes together.
Lazy eye often occurs in people who have crossed eyes (misalignment) or a large difference in the degree of nearsightedness or farsightedness between the two eyes. It usually develops before age 6, and it does not affect side (peripheral) vision.
Symptoms may include noticeably favoring one eye or a tendency to bump into objects on one side. Symptoms are not always obvious.
Treatment for lazy eye may include a combination of prescription lenses, prisms, vision therapy, and eye patching. In vision therapy, patients learn how to use the two eyes together, which helps prevent lazy eyes from reoccurring.
Early diagnosis increases the chance for a complete recovery. This is one reason the American Optometric Association recommends that children have a comprehensive optometric examination by 6 months of age and again at age 3.
Lazy eye will not go away on its own. If not diagnosed until the preteen, teen, or adult years, treatment takes longer and is often less effective.
Strabismus (Crossed Eyes)
Crossed eyes, or strabismus, is a condition in which both eyes do not look at the same place at the same time. It usually occurs in people who have poor eye muscle control or are very farsighted.
Six muscles attach to each eye to control how it moves. The muscles receive signals from the brain that direct their movements. Normally, the eyes work together so they both point at the same place. When problems develop with eye movement control, an eye may turn in, out, up or down. The eye turning may occur all the time or may appear only when the person is tired, ill, or has done a lot of reading or close work. In some cases, the same eye may turn each time. In other cases, the eyes may alternate turning.
Proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion. But over time the brain will learn to ignore the image from the turned eye. Untreated eye turning can lead to permanently reduced vision in one eye. This condition is called amblyopia or lazy eye.
Some babies’ eyes may appear to be misaligned, but they are actually both aiming at the same object. This is a condition called pseudostrabismus or false strabismus. The appearance of crossed eyes may be due to extra skin that covers the inner corner of the eyes or a wide bridge of the nose. Usually, the appearance of crossed eyes will go away as the baby’s face begins to grow.
Strabismus usually develops in infants and young children, most often by age 3. But older children and adults can also develop the condition.
People often believe that a child with strabismus will outgrow the condition. However, this is not true. In fact, strabismus may get worse without treatment. An optometrist should examine any child older than 4 months whose eyes do not appear to be straight all the time.
Strabismus is classified by the direction the eye turns:
- Inward turning is called esotropia
- Outward turning is called exotropia
- Upward turning is called hypertropia
- Downward turning is called hypotropia.
Other classifications of strabismus include:
- The frequency with which it occurs—either constant or intermittent
- Whether it always involves the same eye—unilateral
- If the turning eye is sometimes the right eye and other times the left eye—alternating.
Treatment for strabismus may include eyeglasses, prisms, vision therapy, or eye muscle surgery. If detected and treated early, strabismus can often be corrected with excellent results.
If you or your child are getting headaches or eye strain with a computer or near work, a focusing issue may be the cause. For these reasons, it is very important to get yearly eye examinations to rule out any refractive issues or focusing problems.