Definition & Overview

When the eyes are unable to simultaneously focus on a single object, the condition is called Strabismus. While one eye is focusing on an object, the other eye may be turned inward (cross-eyed), outward (wall-eyed), downward (hypotropia), or upward (hyperopia). Most strabismus cases are present from birth and if the condition is not treated during childhood, it will likely be carried on to adulthood.

A common misconception about strabismus in children is that the affected child will outgrow the condition. Unfortunately, strabismus cannot be cured or corrected on its own. In fact, if left untreated, the condition will likely develop into a condition called double vision.

Most children have the ability to ignore the malfunctioning eye. However, as they grow up, they have a tendency to lose this ability, which is why “double vision” develops. Once this happens, the final result will likely be a condition called a “lazy eye” or amblyopia.

Other than congenital, strabismus can also be caused by other factors, such as a tumour or problems with the nervous system. If the condition develops in adults, it can be a sign of a more serious condition, such as a stroke. Strabismus cases are often identified as either being “large angle” (misalignment is large and obvious) or “small angle” (the problem in alignment is only small and not too obvious).

Large angle cases normally don’t result in symptoms such as headaches or strain, simply because the brain will make no effort to correct the vision. However, these symptoms are present in small angle cases because the person will constantly attempt to view a single picture.

The effects of strabismus are not only limited to vision. Most patients also display some degree of psychological effects because they will constantly be concerned about their appearance. Many even avoid socializing with others because of the fear of being treated differently.

Cause of Condition

Most of the time, the exact cause of strabismus is unknown. However, some people were born with a tumour that affect an eye or have a problem with a specific part of the nervous system that controls the muscles of the eye.

If the condition develops later in life, the major cause is a stroke. Strabismus can also be the result of trauma, thyroid eye disorders, or neurological problems. If trauma caused the condition, it may be because of brain damage, nerve damage, or eye muscle damage.

Key Symptoms

The primary symptom of strabismus is poor vision because of the misaligned eye. Some people may only experience episodes of poor vision because of intermittent strabismus, while others will have to deal with constant poor vision.

If the condition is congenital, those with small angle strabismus may also display other symptoms, such as headaches due to straining, fatigue, and jittery vision. There may also be psychological symptoms because many people with the condition are embarrassed and lack self-esteem.

If the condition was caused by other factors, such as trauma or stroke, other symptoms will also be present and these are similar to those experienced following a stroke or damage to the brain, nerves, or eye muscles.

The symptoms of strabismus will likely to affect the patient’s daily life, which is why it is better to have the condition treated as soon as possible.

Who to See and Types of Treatment Available

Many experts believe that the only effective treatment for strabismus is surgery. However, there are cases wherein non-surgical methods have also proven to be effective. Non-surgical methods include orthoptics and vision therapy. Although the two processes have similarities, there are distinct differences between them.

Orthoptics focus mainly on training the eye muscles, while vision therapy focuses on neurological factors of the condition. In orthoptics, an optometrist will conduct several different exercises that are designed to strengthen the eye muscles. In vision therapy, the optometrist will focus on altering the entire nervous system and reflexive behavior to achieve a lasting cure for the condition.

Both orthoptics and vision therapy are commonly performed at an optometrist’s clinic or office. However, some optometrists also provide instructions on how to perform vision therapy at home. Undergoing the procedures at the clinic while also performing them at home will be more beneficial than performing them at a single location.

Parents or patients (depending on their age) will normally be given a choice of whether to attempt non-surgical methods first or to proceed directly to surgical treatments. Many patients choose to undergo non-surgical methods first. They will only consider surgery if non-surgical methods fail to correct the condition.

Prior to undergoing eye surgery, the patient or parents will be informed of what to expect during and after the procedure. It’s important to understand that strabismus is not only caused by the eye muscles, but by brain functions as well. Providing surgical treatment for eye muscles does not necessarily mean that the brain will automatically adjust to the treatment.

It’s also important to understand that surgical procedures for eye muscles only attempt to correct the appearance of the condition and not to improve a person’s vision. In fact, studies on the results of eye surgeries to correct strabismus revealed that many of the procedures only had “cosmetic” effects, meaning that the appearance of the eyes were corrected but the vision was not improved. For this reason, many patients also undergo postoperative vision therapy to improve their vision.

While treatment for strabismus can be performed at any age, it’s best that the patient receives treatment as early as possible.

References:

  • Cibis GW, Ing M. Binocular vision. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 5.

  • Goldstein HP, Scott AB. Ocular motility. In: Tasman W, Jaeger EA, eds. Duane's Foundations of Clinical Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 2, chap 23.

  • Parks MM. Binocular vision adaptations and maldevelopments monofixation syndrome, microstrabismus, and macrostrabismus. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 8.

  • Olitsky SE, Hug D, Plummer LS, Stass-Isern M. Disorders of eye movement and alignment. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 615.

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