Add your answer... 0. The corneal light reflex, cover/uncover test, and six cardinal fields of gaze are used to assess extraocular muscle function. The corneal light reflex may be used to assess extraocular muscle imbalance. The cover/uncover test is used to determine misalignment of the eye. The function of cranial nerves III, IV, VI and eye movement can be assessed with the cardinal fields of gaze. more.