Convergence insufficiency (CI) is a common eye muscle coordination problem. When reading or doing close work, a person’s eyes must turn in (converge) for the words to be clear and single. This usually happens easily, without thinking. In CI, the eyes do not turn in easily and as a result, extra convergence effort must be used to force the eyes to turn in. This additional effort can cause a number of symptoms such as eyestrain, headaches, blurred vision, double vision, difficulty concentrating, loss of place and concentration, and reading slowly. CI has no obvious signs and is only detected through an eye examination.
Virtually all people that have convergence insufficiency have 20/20 vision. However, it is not enough to have 20/20 vision and be able to see clearly. For the visual system to function properly we must use our two eyes together in a very precise and coordinated fashion. This ability is referred to as eye teaming or eye coordination. The technical term for this ability is BINOCULAR VISION.