A strabismus is an eye condition in which the two eyes are not properly aligned. This causes one eye to be able to focus directly on an object while the other eye is not properly looking at the same object.
Types of Strabismus
There are two main categories of strabismus – vertical and horizontal strabismus. These two types are differentiated by the direction the eye turns away from alignment.
Within the category of horizontal strabismus, there are two main types. There is exotropia where the eye will turn out, away from the nose and line of sight. There is also esotropia where the eye will turn in towards the nose, but still away from the line of sight.
Within the category of vertical strabismus, there are also two types of strabismus. There is hypertropia where the eye is higher than it should be and there is also hypotropia where the eye is lower than it should be.
All forms of strabismus are marked by one of the eyes being turned or rotated away from the proper alignment.
Constant vs Intermittent Strabismus
A strabismus can be either a constant strabismus or an intermittent strabismus. A constant strabismus occurs when at least one of the eyes is always out of alignment.
A constant strabismus may be an alternating strabismus where the eye that is turned and the eye that is fixating can switch between the two eyes, but if the strabismus is constant, there will always be an eye turned away.
An intermittent strabismus occurs when the eye or eyes are not always turned out of alignment. In an intermittent strabismus, there can be times where both eyes are aligned properly and fixate together.
A constant strabismus is often more problematic than an intermittent strabismus as the intermittent strabismus allows occasional fusion with both eyes.
Causes of Strabismus
A strabismus can be due to abnormal eye findings such as a high amount of refractive power in one eye, a reduction in the eyes’ ability to converge or diverge, or if there is an issue with the eyes keeping vision clear and single.
If a strabismus develops later in life, it may be more likely that it is due to an issue with the overall health of the body and the strabismus is a sign of another problem.
A major cause of strabismus is a palsy of the cranial nerve which are responsible for moving the eyes and having the eyes turn in and turn out.
A cranial nerve palsy can occur from a stroke, trauma, or as a result of damage to the blood vessels from a chronic disease like diabetes.
There are multiple options for treating a strabismus or an eye turn.
Initial treatment may include patching the eye, using a medicated eye drop in the turned eye to blur the image, or wearing a specific pair of glasses.
Other interventions include vision therapy and surgery if the strabismus is severe enough.
Depending on the type of strabismus and how the vision in the eye with the strabismus is, it can be determined by an eye doctor.