Binocular vision anomalies are among the most common visual disorders. They are usually associated with symptoms such as headaches, asthenopia, eye pain, blurred vision, and occasional diplopia. About 20% of patients who come to optometry clinics will have binocular vision anomalies. The most effective way to diagnosis vision anomalies is with the near point of convergence test. During the NPC test, a target, such as a finger, is brought towards the face until the examiner notices that one eye has turned outward and/or the person has experienced diplopia or doubled vision.