Strabismus and Amblyopia

Strabismus: Crossed Eyes, Wandering Eyes, or Wall Eye

Strabismus is the inability to point both eyes in the same direction at the same time.

• Esotropia: one eye may turn in relative to the other
• Exotropoa: one eye turns out relative to the other.
• Hypertropia: one eye turns up relative to the other
• Hypotropia: one eye turns up relative to the other

The eye turn may occur constantly or only intermittently. If it is constant, that means that it occurs all or much of the time. Intermittent means that it occurs only some of the time, such as only when a person is tired or has done a lot of reading.

It may alternate, which means that at times one eye turns while at other times, it is the other eye that turns.

Strabismus may cause double vision (diplopia). In order to avoid seeing double, vision in one eye may be ignored (suppressed).

If this occurs from birth or soon after, then the ignored eye does not develop the “wiring” or signal to the brain, and this ends up causing a lazy eye (amblyopia). This means that the wiring between the eye and the brain has not developed. Amblyopia (lazy eye) can occur even if the eyes are pointing straight.

The two main reasons that someone may have amblyopia (lazy eye) without strabismus (an eye turn) is when there is:

• Anisometropia, called UNI-lateral (one eye) amblyopia, is when the powers in each eye are very different from each other and therefore the brain does not develop the information from one of the eye channels.
• BI-lateral amblyopia occurs when there is a large refractive condition in both eyes, most often when there is high hyperopia (farsightedness) in both eyes.

Crossed eyes most often develop in infants and young children, although it can occur in adults. This may also be caused by:

• Inadequate development of eye coordination in childhood.
• Excessive farsightedness (hyperopia) or differences between the vision in each eye. This is termed Accommodative Esotropia.
• Problems with the eye muscles that control eye movement.
• Head trauma, stroke, or other general health problems.

Treatment for Strabismus
In most cases the problem does not improve as the child grows. Treatment varies depending on the cause of the eye-turning, and may include:

• Eyeglasses
• Vision Therapy
• Prism
• Eye muscle surgery

Eye muscle surgery can sometimes make the eyes appear to others as if it is straight, but it rarely aligns with the other eye, and the amblyopia continues. A program of Vision Therapy is usually needed in order to restore visual function and the ability to use the two eyes together as a team.

Binocular Vision
Our two eyes are intended to work together as a binocular system. When our two eyes work together well, we can easily and efficiently measure the location of objects in relation to ourselves. This is termed depth perception. Binocular vision makes it easier for us to ride a bicycle, drive a car, or direct many other daily activities.

An eye that wanders is much more than just an appearance problem. For example, reading demands accurate binocular vision. When a person’s eyes do not aim at the same place accurately and simultaneously, he or she will have much more difficulty with large amounts of reading, writing, and other close work.

Treatments for strabismus involves lenses, prisms, and vision therapy. Some doctors still advocate patching one eye, although patching does not help the person gain the ability to use the two eyes together. Please read the page on amblyopia, as amblyopia can occur in certain cases of strabismus. If this is confusing, don’t worry, your not alone. We will be happy to explain it when you are in office.

What is the best (and more permanent) way to treat Amblyopia, commonly known as “Lazy Eye”?

Patching and Atropine are commonly prescribed by many eye doctors, but it doesn’t get at the core of the problem.It addresses Amblyopia as though it is a problem in one eye only, when, in fact, amblyopia is really a binocular (2 eye) problem..

Patching or Atropine yields some benefit, short term, but it really doesn’t address the underlying problem and does not solve it. Vision Therapy does.Here is a link to a study: “Amblyopia and the Binocular Approach to its Therapy”: https://www.sciencedirect.com/science/article/pii/S0042698915000528