What does having a patient follow a finger in the 6 cardinal positions of gaze evaluate?

The evaluation of a patient's ability to follow a finger in the six cardinal positions of gaze is primarily designed to assess extraocular muscle function. This test helps determine whether the muscles that control eye movement are working properly. When patients are asked to follow an object through these specific positions, it allows the examiner to observe the coordinated movement of both eyes as they track the target in different directions. This can reveal issues such as strabismus, muscle weakness, or neurological conditions affecting eye movement.

While the other options mention important aspects of eye examination—such as visual acuity, depth perception, and pupil response—they are evaluated through different tests. Visual acuity assesses how well a patient can see at varying distances, depth perception tests often involve specific tasks that evaluate binocular vision, and pupil response tests gauge the reflexes of the pupils to light. In contrast, the cardinal positions of gaze specifically focus on the functionality of the eye muscles, making it critical for diagnosing issues relating to extraocular muscle integrity and coordination.