What is convergence insufficiency (CI)?
Convergence insufficiency (CI) is a vision disorder. It is a disorder involving binocular vision — vision using both eyes.
Convergence describes the way our eyes move together and point inward when we look at near objects. With CI, the eyes do not point together inward as one looks at objects close-up.
CI affects children and adults. It often goes undiagnosed. Doctors who do diagnose it often identify CI when children are learning to read.
How common is convergence insufficiency (CI)?
CI occurs in an estimated 2 to 13 percent of people in the U.S.
Symptoms and Causes
What causes convergence insufficiency (CI)?
Problems coordinating the eye muscles and eye movements cause CI. Instead of coming together to focus on near objects, one or both eyes remain pointing away from the target. Eye movements are controlled by the brain. The eye muscles themselves are normal in patients with CI. In some cases, a brain injury or neurodegenerative disease (cells in the nervous system stop working) such as Parkinson’s disease can cause CI.
What are the symptoms of convergence insufficiency (CI)?
People with CI may experience several symptoms when reading or looking at objects close-up. These symptoms include:
- Double vision
- Written words that look blurry
- Difficulty concentrating on close-up materials, such as on a cell-phone
Diagnosis and Tests
How is convergence insufficiency (CI) diagnosed?
Eye specialists called optometrists or ophthalmologists diagnose CI. They take your medical history and perform a complete vision exam.
A routine eye exam with the familiar 20/20 eye chart does not diagnose CI. People can pass the standard eye exam even if they have CI.
A specialized CI evaluation measures the ability of the eyes to converge when looking at an object as it moves closer to the face.
Management and Treatment
How is convergence insufficiency (CI) managed or treated?
Eye movement exercises treat CI. These exercises improve the eyes’ ability to move inward together. They may be performed with an orthoptist or therapist in the doctor’s office and repeated at home. Occasionally patients require prism glasses.
Eyeglasses, eye patches or surgery usually don’t improve CI.
What complications are associated with convergence insufficiency (CI)?
In some people with CI, the brain suppresses (shuts down) vision in one eye to avoid experiencing double vision. Most of the complications associated with CI relate to the discomfort it creates and the interference with activities that require near vision. There are no effects on eye health.
What are the risk factors for convergence insufficiency (CI)?
People with brain injuries often develop CI. Doctors have not identified any other risk factors.
Can convergence insufficiency (CI) be prevented?
Because doctors do not know what causes the poor muscle coordination of CI, you cannot prevent it.
Outlook / Prognosis
What is the prognosis (outlook) for people with convergence insufficiency (CI)?
Most people who undergo eye exercise treatment for CI experience fewer symptoms and improved vision.
When should I call the doctor?
Contact your child’s doctor if he or she experiences symptoms of CI when doing up-close work such as reading.
What questions should I ask my doctor?
If you have CI, you may want to ask your doctor:
- Have you performed the necessary test to diagnose CI?
- Can you refer me to someone who can administer the exercise treatments?
- How long will treatment take?
When can I go back to my regular activities?
People with CI go back to their normal activities immediately. With treatment, close-up activities such as reading and studying will become more comfortable.