When we use near vision for reading, we turn both eyes inward (converge) to focus on the page.
With convergence insufficiency (CI), the eyes don’t converge enough for near vision. The binocular function (both eyes working together) we use to read is impaired. One or both eyes may turn outward while reading. This makes reading or working on the computer difficult.
Anyone can develop CI, but it is most common in children and young adults.
What Causes Convergence Insufficiency?
The cause of CI is not fully known. It’s thought to be linked to a weakness in the muscles and nerves that control eye movement.
Who Is at Risk for Convergence Insufficiency?
People with a family history of CI are more likely to have it.
Acquired CI (getting it later in life) can be caused by:
- trauma (injury)
- diseases affecting the brain
- autoimmune disease (when the body attacks its own tissues and organs) that harm the eye muscles
Some children with CI may also have learning disabilities. But it’s important to note that learning disabilities are not caused by CI or other eye problems. Learning disabilities are caused by problems with how the brain processes information.
What Are Symptoms of Convergence Insufficiency?
People notice symptoms while reading or doing other near work. They include:
Symptoms of CI vary, and patients may be bothered by one or more. Taking breaks from reading to rest your eyes helps reduce eye strain, fatigue and other symptoms.
Diagnosis of Convergence Insufficiency
CI is usually not found during school vision screenings. An ophthalmologist or orthoptist diagnoses CI. They will:
Some people are diagnosed with CI but are asymptomatic (have no symptoms). They can do near vision tasks without difficulty. Those patients do not need treatment but should tell their doctor if symptoms appear.
How Is Convergence Insufficiency treated?
CI is treated with exercises that improve convergence.
Your orthoptist or ophthalmologist may prescribe in-office exercises, exercises to do at home, or both. There are also computer-based exercises. You and your doctor can decide the best way to do them. They will give you the exercise materials and instructions.
Exercises are not recommended for all cases of CI.
Eye exercises successfully treat the symptoms of CI in about 70 percent (7 out of 10) of patients. Sometimes, CI comes back after successful treatment with exercises. Restarting the eye exercises may help the CI symptoms go away again.
Other treatments for CI include:
- glasses with prism to reduce double vision
- surgery—in rare cases—to strengthen the eye muscles