Monocular eye closure in bright illumination is a common occurrence in intermittent exotropia. In a series of patients with intermittent exotropia with normal retinal correspondence and stereopsis while the eyes were in the straight position, monocular eye closure occurred in 90% of patients with normal retinal correspondence while exotropic and in only 35% of patients with abnormal retinal correspondence while exotropic. Monocular eye closure occurs in people with intermittent exotropia to avoid diplopia and visual confusion even though these are not usual complaints. The cortical adaptation of anomalous retinal correspondence prevents diplopia and visual confusion and obviates the need to close one eye in bright sunlight.