Visual Pursuit Test – Cranial Nerves 3, 4 & 6: The Oculomotor,Trochlear, & Abducens Nerves

Definition:

Ocular movements are controlled synergistically by a group of muscles, supplied by three cranial nerves: Oculomotor, Trochlear and Abducens.

The visual pursuit test aims to assess the proper function and integrity of these nerves and associated musculature.

Test procedure:

The visual pursuit test is performed by asking the patient to follow the practitioner’s finger or the tip of a pen with their eyes whilst keeping their head still. The examiner moves the object in a vertical, horizontal and diagonal axis, asking the patient to follow the movement only with their eyes. This test is done under the assumption that the examiner’s visual fields are intact.

Test findings (inc Positive & Negative results):

With proper functioning of the ocular muscles and cranial nerves, the patient should be able to follow the practitioner’s finger or pen tip in all the different planes without experiencing any diplopia, strabismus, or nystagmus.

Findings outside of the aforementioned may be indicative of a pathology.

Considerations:

Strabismi and nystagmi may be of a sinister origin, though these are also a common benign finding. An extensive and thorough clinical picture is invaluable in determining the exact cause.

Diplopia may be the result of a muscular or neurological lesion/deficit, whereby the left and right eyes are not focusing on the same point at the same time.