Eyes are considered very important organs in life, especially when we are still children, because almost all learning requires vision. Therefore, the eyes are an important part of physical, mental, emotional, and sensory development. If the eyes have abnormalities that reduce the level of vision, such as strabismus, it will cause problems in one way or another.
What is Strabismus?
Strabismus is a condition where both eyes are not aligned and do not work together, for example, the eyes may turn inward, outward, upward, or downward when looking at the same object. The patient will use only the normal eye to look at the object, while the eye that is crossed or turned will not be used.
Causes of Strabismus?
Strabismus occurs due to imbalance in the eye muscles or weak eye muscles. Some cases have strabismus from birth or it may develop later. Medically, strabismus can be inherited genetically, and there are many factors that trigger different types of strabismus, such as
- Congenital Strabismus
occurs in newborns or may develop within 6 months after birth due to uncoordinated eye muscle function. Most cases are inward turning (Congenital Esotropia / Infantile Esotropia) or outward turning (Congenital Exotropia).
- Strabismus Related to Refractive Errors
can be caused by nearsightedness, farsightedness, or astigmatism, which result from abnormal refraction of light passing through the lens. Commonly, children with moderate farsightedness have inward strabismus because they need to focus more to see clearly.
Additionally, children with central nervous system abnormalities, such as those with Down syndrome or delayed physical development, have a higher chance of having strabismus than other children.
Types of Manifest Strabismus
Manifest strabismus is a type of strabismus that can be clearly seen. It has several forms, including
- Inward turning (Esotropia)
characterized by the pupil of the crossed eye turning inward or toward the nose. This type is more common than others and is often found in infants aged 4 months or older. It may be called congenital esotropia (Crossed eye). It is believed to be caused by visual abnormalities, making the child focus excessively on near objects, causing the pupil to turn inward, or due to imbalance in the nerve control of eye muscles.
- Outward turning (Exotropia)
characterized by the pupil of the crossed eye turning or slanting outward toward the ear. This type is less common than esotropia and is rarely seen in children. It is often associated with nearsightedness or conditions such as corneal disease, cloudy lens, vitreous opacity, narrow pupil, or retinal nerve abnormalities, causing the eye to be unable to focus and thus turn outward. People with this type often have a history of trauma. - Upward turning (Hypertropia)
characterized by the pupil of the crossed eye drifting upward. It may be caused by abnormalities of the eye muscles and is a rare type. - Downward turning (Hypotropia)
characterized by the pupil of the crossed eye drifting downward. This type results from abnormalities of the eye muscles or scarring of the eye muscles after injury, causing the eye to be pulled downward. It is also a rare type.
What is Pseudostrabismus and its Characteristics?
Pseudostrabismus is a condition seen in children whose nasal bridge is still flat with the skin and the inner eye corners are wide, making it look like the eyes are turned inward. However, as the child grows and the nasal bridge becomes higher, this appearance disappears. Pseudostrabismus may also be caused by
- a narrow face, causing the eyes to be very close together, even if the nose is prominent, making it look like inward strabismus
- a wide face, causing the eyes to be spaced wider than normal, making it look like outward strabismus
How is Strabismus Treated?
Children should receive a thorough eye examination, including retinal examination to detect any internal eye abnormalities that may cause strabismus, and receive appropriate treatment. Most strabismus cases respond better to early treatment. If the child also has amblyopia, the doctor may treat the amblyopia first before treating the strabismus. Treatment for amblyopia may involve glasses or patching the normal eye, depending on the cause of amblyopia.
If strabismus is left untreated until the child is older, treatment will only be able to realign the eyes through surgery but will not restore normal clear vision. The coordinated function of both eyes, especially three-dimensional vision (stereopsis), will also be lost.
