Strabismus is the misalignment of the eyes.
If the muscles of one eye do not work in a coordinated manner with those of the other eye, strabismus occurs, that is, a deviation of the eyes commonly known as “crossed eye.”
It produces a loss of stereoscopic vision (depth) that may be reversible depending on the age of the patient and the type of strabismus, and can produce amblyopia of the deviated eye (lazy eye) that may require treatment with optical correction and patching.
Convergent strabismus: This is the most common type of strabismus, when the eyes deviate towards the nose. It is called esotropia. It can be corrected with optical correction (glasses), surgery or a combination of both. The so-called accommodative esotropia is treated with glasses and surgery is not necessary. However, there are other strabismus that improve with glasses, but are not completely resolved, so surgery and glasses will be necessary (partially accommodative esotropia). The third group, non-accommodative esotropia, cannot be corrected with glasses and requires surgery.
Divergent strabismus: These are eyes that deviate outwards. They are the second most common. They tend to become unbalanced in situations of looking far away, tiredness, stress, when the person distracted or bothered by bright light. They can improve with optical correction but most require surgical intervention. They are called exotropias.
Vertical strabismus: The eye deviates upwards or downwards. These are called hypertropia or hypotropia respectively. They usually require surgical correction.
Congenital strabismus: Present at birth and not usually improved with glasses, they require surgery in the vast majority of cases.
Normal eyes
Convergent strabismus
Divergent strabismus
Vertical strabismus
Strabismus is mainly manifested by the deviation of one of the eyes. This deviation can be constant or intermittent, manifesting at certain times or during specific jobs. In some cases, we can also detect an abnormal position or bad posture of the head, which is called torticollis. Other times, we can observe bad body posture and decreased visual acuity in one of the eyes, “lazy eye”, double vision, pain, poor judgment of distances and relief.
It is one of the most common eye conditions in children, so early detection of the cause of strabismus by a specialist ophthalmologist will allow the eye to develop effectively.
There may be many causes of strabismus: one eye has a greater refractive defect than the other (causing poor vision in the latter and causing the brain to eliminate this image and deviate the eye), high refractive defects in both eyes, some loss of vision in one of the eyes (congenital cataracts), primary defects in the eye muscles responsible for eye movements and even neurological diseases. In general, we can say that eyes with poor vision tend to deviate, so it is very important, if any suspicion of an eye deviating, to visit a doctor specialising in ophthalmology and strabology.
Intermittent deviation of the eyes before 6 months of age is normal. Any permanent deviation (before or after 6 months of age) or an intermittent deviation that persists beyond 6 months of age is not normal and requires a visit to an ophthalmologist.
Strabismus can only be diagnosed by a strabologist, but the deviation of one eye at certain times is a sign of intermittent strabismus.
There is a certain hereditary component of strabismus, or what is more common, of inheriting the cause that created this strabismus, so it is important to do a family examination if there is a member who suffers from strabismus.
Some types of strabismus can affect the child’s development in terms of depth perception, causing a slower development when walking and interacting with things. At school age, it can affect the ability to read and write, so an adequate assessment of vision and mobility is necessary if these problems appear or are suspected.
A true strabismus does not cure itself, it always requires clinical and/or surgical treatment depending on the case. Sometimes there are cases that simulate or look like a strabismus, but in reality they are not: this is called “pseudostrabismus” and is generally due to the appearance and configuration of the eyelids or the bridge of the nose. It may disappear as the child grows.
As we have mentioned, strabismus can be caused by several factors, so the strabologist will determine the cause of the strabismus and treat it. Among the different treatments there would be the correction of refractive defects, eye occlusions, surgery or injections of substances such as botulinum toxin.
