The aim is to circumvent the tendency to suppress the field of view of the weaker eye and to train the capacity for binocular vision.
[2] An alternating occlusion device (the so-called Translid Binocular Interaction Trainer (TBIS) operating at a rate of 9 to 11 Hz) was introduced by Merrill Allen in 1967 to favor parallel processing of the eyes.
[1] Reported results of the use of alternating occlusion devices include improved vision, as well as occasional side effects of headaches or discomfort.
[5] It was found that the flicker rates of 9 to 11 Hz that were employed in the TBIS device are slow enough and the stimulus weak enough to avoid any risk of epileptic seizure.
Strictly speaking, alternating occlusion is a form of visual deprivation and as such may have negative effects during a critical period of development.