The cover-uncover test is used to detect heterophoria or abnormalities in conjugate gaze. To perform:
- Ask the patient to look at an object at the end of the room
- Cover the patient’s left eye with your right hand watching for movement in the uncovered right eye to take up fixation
- Uncover the left eye
- Cover the right eye with your left hand watching for movement in the uncovered left eye to take up fixation
- If there is fixation movement, the patient has heterotopia (strabismus)