Recovering right III nerve palsy. Minimal RE ptosis. Patient is looking up and to the right. Cover-uncover of RE, no movement of the LE. Cover-uncover of the LE, upward movement of the RE; right superior rectus underaction. Movement of RE becomes greater, more easily observed with alternating cover test. This reveals overaction of the contralateral synergist in the LE; in this case the left inferior oblique. When the LE is covered with the patient looking up and to the left there is no observed movement of the RE. When the RE is covered the LE moves down slightly. During the alternating cover test the RE moves upwards to take up fixation indicating a right inferior oblique underaction. The LE can be seen to move down to take up fixation indicating overaction of the contralateral synergist, left superior rectus.