These are two common vision problems in children. If not treated, these problems can permanently affect a child's eye sight. A child will not outgrow strabismus or amblyopia, but both can be treated. Early eye exams and the right treatment can improve a child's vision.
Strabismus occurs when a child's eyes are not aligned (straight). This means the eyes do not work together, which can prevent normal vision from developing. If it is not treated it can lead to amblyopia.
What is amblyopia? It is poor vision that occurs when the brain ignores one or both eyes. This often means only one eye is being used. If not treated early, amblyopia may keep a child from developing normal vision.
When the eyes don't work together, the brain has trouble interpreting what's being seen. Things that can keep the eyes from working together are:
- Alignment problems (strabismus) one eye looks in a different direction from what it's trying to see. This maybe constant (all the time) or intermittent (some of the time).
- Focusing problems - one or both eyes have trouble focusing. The brain receives blurry pictures. Focusing problems include being:
- Nearsighted - distant objects appear blurred
- Farsighted - near objects appear blurred
- Astigmatism - both near and distant objects appear blurred
Most children should have their first eye exam by the time they start school. At the doctor's visit an evaluation of health history will be performed. This is to determine if health problems could be affecting the child's vision.
- Testing vision is the next step in the process. The testing of visual acuity is to find out how well the child's eyes see and whether the eyes have trouble focusing.
- The doctor will test for binocular vision, to see whether the child's eyes are working together, and whether the brain is fusing images.
- He will also test eye movement to see how well the child's eyes move and whether they move together.
- He will then test eye alignment to see if the child's eyes are aligned and are focusing together.
If a diagnosis of strabismus is given, this means the eyes are not aligned. One eye may turn in, out, up or down, while the other looks straight ahead. When the eyes aren't aligned, pictures sent to the brain are too different to be fused into one image.
What causes Strabismus?
There are 2 main causes:
- focusing problems (such as being farsighted) this can cause an eye to turn in when trying to focus
- eye muscles that are unable to keep the eyes aligned
What is esotropia? This is an eye that turns in, and is sometimes called being "cross-eyed".
What is exotropia? This is when an eye turns out, and is sometimes referred to as being "wall-eyed".
Treatments for Strabismus
This is done by correcting the problem that's making the child's eyes turn.
- wearing eye glasses
- surgery is sometimes needed to align the eyes and treat strabismus
- patching is occasionally done to strengthen vision
The doctor's goal for treatment would be to:
- correct the problem that's causing the eyes to turn
- align the eyes
- improve sight in both eyes as much as possible
- make the eyes work together
Strabismus In Adults
Most adult strabismus is simply persistent childhood strabismus. Strabismus which occurs in adulthood without a history of childhood eye misalignment should be evaluated carefully for medical or neurological causes such as diabetes, thyroid disease, myasthenia gravis, brain tumors, or strokes.
What are the symptoms of adult strabismus? If strabismus has been present since childhood, symptoms are usually minimal. If the strabismus develops late in childhood or as an adult, the most common symptom is double vision.
What causes double vision? When the eyes are misaligned each eye sees a separate image.
How is adult strabismus treated? There is a common misconception that strabismus is difficult or impossible to treat. Actually, adults with strabismus have many treatment options including:
- prism glasses
- eye muscle surgery
- oculinum injections
An adult does not need to live with misaligned eyes. Advances in techniques allow excellent chances of improved alignment and appearance for most individuals.
Amblyopia is when the brain ignores signals coming from one eye. Over time, the brain gets used to working with only one eye. The eye being ignored doesn't develop normal vision. Making the brain use both eyes and getting the eyes to work as a team becomes harder as the child grows. It is best to treat as soon as possible.
What causes Amblyopia?
- poor vision in one eye
Treatment for amblyopia is most often treated by blocking one eye to keep it from doing all the work. The brain can learn to accept signals from the eye that's being ignored. Gradually, vision may improve.
Methods of treatment
- Patching - an eye patch is placed over the eye that's being used. With the eye patched, the brain is forced to start working with the eye it's ignoring. The doctor will instruct how to patch.
- Medicated eye drops - Atropine is an eye drop that can be used instead of patching. Drops are put in the eye that's being used, blurring vision in that eye to keep it from doing all the work.
- Eye glasses - can help correct focusing problems. They can also be prescribed to blur sight in the eye that's being used. This forces the brain to work with the eye it's ignoring. In some cases, sight in one eye is blocked by sticking a patch or a filter to the inside of an eyeglass lens. As vision improves, the child's eyeglass prescription may change.
As the child's vision improves, their treatment needs may change. But the goals stay the same: to help each eye see as well as it can, and to allow both eyes and the brain to work as a team. Treatment may take weeks or months. At follow-up visits, the doctor will check how well treatment is working. Techniques make it possible to test vision in infants and young children. If there is a family history of misaligned eyes, childhood cataracts, or a serious eye disease, an eye doctor should examine the eyes during infancy.