Esotropia is a type of strabismus in which eyes do not line up properly. A less medical term that you could possibly hear is ”crossed eyes”. The muscles that normally control the eyes are not synchronized as they should be. In this eye disorder, one or both eyes point inward. It can affect only one eye (monocular) or both eyes (binocular). The prevalence of strabismus is estimated at 1%–3% of the population.
Risks
Risk factors for the development include family history, meaning strabismus can be inherited. However, if someone in your family has esotropia, it does not mean that you or your children will have it too. Esotropia can be a sign of a variety of different disorders, including a condition within one or both eyes, issue with your brain (stroke), neurological disorders, systemic conditions (diabetes), eye injury, and thyroid disease.
Symptoms
The most obvious and visible symptom is the eyes that turn inward towards the nose. In other words, the eyes that don’t move in synchrony. Squinting and excessive blinking can also signalize esotropia. Another symptoms include low vision, blurry vision, double vision, decreased visual field and problems with depth perception. Individuals with esotropia are often farsighted, which means they can see objects farther away more clearly than things closer to them.
Types of esotropia
BY AGE
Esotropia can be classified by age. If so, the distinction is between congenital (infantile) and acquired. Infantile esotropia happens in the first year of life. The exact cause is unknown. We know that some youngsters have trouble utilizing both eyes simultaneously, but with early surgery, these children can learn to use both eyes simultaneously. If one eye turns in more frequently than the other, the eye that crosses more frequently is at a higher risk of developing amblyopia. Acquired esotropia refers to those who develop crossed eyes later in life. Individuals suffering from this type of esotropia typically experience double vision. Normally, individuals detect condition really quickly as everyday tasks become difficult.
BY FREQUENCY OF OCCURRENCE
Esotropia can also be classified based on how often it occurs. If eyes are directing inward all the time, this is a constant esotropia. Most occurrences are constant. If it happens from time to time, the condition is called intermittent esotropia. For example, accommodative esotropia can be intermittent. However, without treatment, intermittent will most likely progress to constant.
BY EYE FOCUSING
Accommodation is a term that describes the focusing effort. Accommodative esotropia, also known as refractive esotropia, is eye crossing caused by the eyes’ focusing efforts to see clearly. If glasses can fully fix the condition, this is a fully accommodative esotropia. If not, it is characterized as partially accommodative. A non-accommodative esotropia occurs when there is no change in the angle of strabismus when wearing glasses. This condition is not related to refractive issues, but to other central nervous systems.
Treatment
Severity and duration of the condition determines treatment options. Treatment plan will also differ depending on whether the misalignment affects one or both eyes.
Glasses or contact lenses aim to correct refractive error. In most cases, corrective lenses will quickly resolve the over-focusing issue. Some people, however, may still have esotropia while performing specific tasks.
Prisms lenses alter the way light enters the eye. Therefore, lenses lessen the effort required by the misaligned eye when focusing on an item, hence improving the condition.
Vision therapy (orthoptic treatment). For instance, your doctor may advise you to wear an eye patch over the unaffected eye. This pushes you to use your misaligned eye, which strengthens it and aids in vision improvement. It may also advise you to use vision therapy software, such as AmblyoPlay, which offers monocular and binocular mode. The latter teaches the brain and the eyes how to work together simultaneously.
Surgery
In severe cases, surgery may be an option. This therapy strategy, however, is mostly used for infants. The goal of surgery is to straighten the eyes by correcting the length of the muscles around the eyes.
What if you do not treat esotropia?
If left untreated, esotropia can lead to eye issues such as binocular vision issues, double vision, loss of three-dimensional vision, and even vision loss in one or both eyes. Therefore, it is important to minimize the risks over which we have influence, detect possible symptoms, and visit an optometrist or ophthalmologist.
Sources:
https://aapos.org/glossary/infantile-esotropia
https://www.verywellhealth.com/esotropia-crossing-of-the-eyes-3421583
https://my.clevelandclinic.org/health/diseases/23145-esotropia
https://www.healthline.com/health/esotropia#treatment