Strabismus: Causes, Symptoms, And Treatment For Wandering Eyes

Strabismus, commonly referred to as crossed eyes or wandering eyes, is an eye condition in which one or both of the individual’s eyes are misaligned. This condition is particularly common among young children, often from birth. According to the American Academy of Ophthalmology, four percent of all children in the United States have some form of strabismus. While it is most common in children, this condition can also develop later in life. Some reports indicate there is a genetic component to strabismus as well, although many individuals with this condition have no relatives who also have it.

Types Of Strabismus

The types of strabismus are esotropia, where one or both eyes turn inward, exotropia, where one or both eyes turn outward, hypertropia, where the misaligned eye turns upwards, and hypotropia, where the misaligned eye turns downward. The turning might be consistent or come and go, and the affected eye(s) may also change depending on the case. Patients often hear the term lazy eye used to describe strabismus, but lazy eye is another condition called amblyopia, which is different from strabismus, though often occurs as a result of strabismus.

The most common types are esotropia and exotropia, particularly esotropia, which is why many individuals refer to strabismus as crossed eyes, the term used to indicate how the eyes appear when turned inward. Turning inward normally occurs when the infant or child is attempting to focus their eye or eyes at a distance, up close, or even both. Turning outward is most common when the individual is trying to focus at a distance, and often worsens when they are daydreaming or ill.

Causes Of Strabismus

Everyone’s eyes are controlled by muscles, which are in turn controlled by the brain. Each eye has six muscles: one moves the eye left, one moves the eye right, and the remaining four eye muscles move the eye up and down. For the eyes to be appropriately aligned and to focus straight on a single object, the muscles must be balanced and work together at the same strength level. Misalignment occurs when one or more of the muscles are weaker than the others. The specific weak muscle will determine the type of strabismus the individual has.

Aside from weakened eye muscles, other causes of strabismus in children include medical conditions affecting the brain, such as cerebral palsy, Down syndrome, Duane syndrome, and hydrocephalus. Eye injuries and cataracts or suffering a stroke may also result in strabismus. However, the majority of children with strabismus do not have an associated medical condition, making weakened eye muscles the most common reason behind strabismus in children.

Symptoms Of Strabismus

The most significant symptom of strabismus in patients regardless of age is one or both eyes not looking straight (e.g., the right eye turning inward whereas the left remains straight). Another potential symptom includes the patient tilting their head to use both eyes. It is also important to note when an infant or young child has strabismus, their brain will eventually learn to ignore the image from the misaligned eye and will only focus on the ‘straight’ eye.

However, if the brain always ignores the signals from the misaligned eye, the eye in question will not develop good vision and may even lose their sight partially or entirely. Thus, poor vision can be a symptom of strabismus in young children, although this symptom is also nonspecific and could point to another condition. It is also not the same in older children and adults who have had the time to develop their vision properly. Instead, a key symptom among adults who might have strabismus is double vision, since their brain processes the images from both eyes.

Diagnosing Strabismus

All children should receive a complete eye exam from their pediatrician when they are around three years of age, regardless of any indicators (or lack thereof) of any eye conditions. However, if the parents do notice their child has one or both eyes not looking straight before then, they should book an appointment for a vision test. Parents should also have their child’s vision checked before three years of age if there is a family history of wearing eyeglasses or of strabismus specifically.

Early detection of strabismus is the key to effective treatment and minimizing potential lasting effects. If the child fails a standard vision test or exhibits the physical symptom of strabismus, most pediatricians will refer the family to an ophthalmologist, who will conduct further tests and is better equipped to recommend specific treatments.

Treatment Options For Strabismus

There are three forms of treatment available for strabismus: eyeglasses, eye patches, and eye surgery. Since each case is different, an ophthalmologist can recommend one of these treatments or a combination of them. In all instances, however, early treatment is essential for the best results and minimizing lasting effects. Infants and very young children with strabismus will almost always require surgery to realign the eye(s), although some ophthalmologists will try eye patches or glasses first to train the eyes and the brain.

During strabismus surgery, the ophthalmologist will remove and reattach sections of eye muscle as necessary to strengthen or weaken a particular muscle to make it shift towards the center and look straight. However, the ophthalmologist may not be able to align the eye completely. If this is the case, they will almost always write a prescription for glasses to complete the alignment.

Wearing Glasses To Treat Strabismus

When an ophthalmologist prescribes glasses for strabismus, the child needs to wear them all the time for the best results. It is not like an adult who needs reading glasses. The prescription will adjust how light reflects and make it easier for the affected eye to focus so the eye no longer over-focuses and turns in another direction. Some children grow out of the need to wear glasses to align their eyes, but many will wear them throughout their adult lives, often to reduce headaches, since it requires more strength to align the eye without glasses, or simply because they are used to wearing glasses at this point.

Parents should have their child return for an annual visit to check on their eye development and adjust the prescription as necessary. The ophthalmologist will eventually recommend parents take their child to an optometrist when they are no longer concerned about the possibility of further surgery. The optometrist will take care of the eye exams and prescriptions from there. As the child reaches adulthood, they will often be able to reduce the number of visits to once every two years instead of once a year.