What are Crossed Eyes?
The crossed eye is a condition in which the eyes do not align properly and do not work together. In it, the eye points in different directions which may lead to difficulty in vision. Medically, a crossed eye is known as strabismus.
When a person has normal vision the eyes point in the same direction, which helps in seeing properly. In the crossed eye, one eye points forward while the other eye may point inward or downward.
It may affect one eye or alternately the eye may point in different directions. In the United States, it is estimated that 4% of the population has crossed eyes.(1)
Signs of Crossed Eye
The signs that may show a person has crossed eye include:(2)
- Misalignment of eyes
- Eyes would not move together at the same time
- A person may tilt his head while looking at something
- Problems with the perception may also cause crossed eyes
The signs of misaligned eyes can be seen in children aged 3 years or above.(3) It may also occur occasionally and the child may be found tilting his head from side to side.
Crossed eye or strabismus can be classified into different types:
- Esotropia which is the term used for the inward turning of the eyes
- Exotropia which is the outward turning of the eyes
- Hypertropia or the upward turning of the eyes
What Causes Crossed Eyes?
There are muscles that control eye movements. They allow the eye to move at different angles i.e., up, down, right, and left. These muscles are controlled by the brain to work together and for the eye to focus on a single point.
Any problem, affecting these muscles may lead to crossed eyes. These include the following:
- Health conditions including diabetes, Graves’ disease, stroke, thyroid disease, and myasthenia gravis.
- Injury to the head or trauma
- Damage to the eye muscles that may be caused by eye surgery or trauma
- It is a very common condition to occur in childhood but can develop in later years of life as well.
- One of the most common causes of esotropia is far-sightedness.
The crossed eye may occur commonly in children even with no other health condition. It is more common in children who are premature and have brain disorders, brain tumors, or down syndrome.
The risk factors for crossed eyes include:
- A parent or a sibling with crossed eyes
- Uncorrected farsightedness
How is Crossed Eye Diagnosed?
To diagnose crossed eyes, a doctor may take the medical history of a person, assess symptoms, and carry out a range of tests. The test needed for diagnosis of the crossed eye include:
- Visual Acuity: During the test the person has to read letters from different distances to check how close they need to be to the letter to see it clearly.
- Refraction Assessment: Different lenses are placed in front of the eye to check if a person needs lenses to compensate for the vision problem.
- Alignment and Focusing: This test may show how well the eyes are able to move together and focus on a single image.
- Eye Health Examination: The health of the internal and external structures is examined by the doctor to check for any eye diseases. Eye drops may be used by the doctor to affect how the eyes focus temporarily.
All these tests help in diagnosing whether a person has crossed eyes and requires treatment or not.
Treatment for Crossed Eyes
The treatment for crossed eyes includes the following.
- Eyeglasses: Wearing corrective eyeglasses may be helpful in correcting the crossed eye in some individuals.
- Prism Lenses: Prism lenses have one lens thicker than the other. These help in altering the amount of light that enters the eye, bending the direction of the light. This makes the two images from two lenses appear closer. This reduces the need to turn one eye to see clearly.
- Vision Therapy: Eye exercises help in improving eye focus and help them move together. It helps in supporting the connection between the brain and eyes helping them work better together.
- Surgery: Surgery can be helpful in altering the length and position of eye muscles and help in straightening them. Vision therapy may be needed after eye surgery to prevent the eyes from getting crossed again.
- Botox: Injection of botulinum toxin is given into the eye. It works by paralyzing the muscles that prevent proper eye alignment. This treatment may last for a few months and may also lead to permanent improvement.
The crossed eyes can be corrected with early diagnosis and treatment. People can also go ahead with the treatment later in life and not suffer from any discomfort or vision problems due to this condition.(4)