What causes convergence insufficiency (CI)?

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.