Advanced Binocular Vision (ABV) Exam 2 Practice

Testing for monocular suppression in a binocular field depends on creating a controlled difference between the eyes without fully occluding either eye. Placing a single red lens over one eye does just that by dimming that eye’s input relative to the other eye. With both eyes open and a common fixation target, the brain’s tendency to use the clearer image reveals whether the eye under the red lens is being suppressed. If suppression is present, the patient mainly perceives the target through the other eye, indicating the hidden eye’s input is being suppressed; if there’s no suppression, fusion occurs and the patient sees a single combined image. This method is preferred because it is quick, preserves binocular viewing, and uses a simple, well-tolerated tint. Full occlusion with tape would remove binocular input entirely, which isn’t how suppression is assessed in a binocular field, and using green or blue filters is less standard for this purpose.