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Extraocular muscle function testing

Definition

Extraocular muscle function testing is an examination of the function of the eye muscles. A doctor observes the movement of the eyes in six specific directions.

Alternative Names

EOM; Extraocular movement; Ocular motility examination

How the test is performed

You are asked to sit or stand with your head erect and a forward gaze. Your health care provider will hold a pen or other object 12 inches in front of your face. He or she will then move the object in several directions and ask you to follow it with your eyes, without moving your head.

How to prepare for the test

No special preparation is necessary for this test.

How the test will feel

The test involves only normal movement of the eyes.

Why the test is performed

This test is performed to evaluate any weakness or other problem in the extraocular muscles, which may result in double vision or rapid, uncontrolled eye movements.

Normal Values

Normal movement of the eyes in all directions.

What abnormal results mean

Eye movement disorders may be due to abnormalities of the muscles themselves or problems in the sections of the brain that control these muscles. Your doctor will discuss any abnormalities identified.

What the risks are

There are no risks associated with this test.

Special considerations

Slight nystagmus with an extreme sideways gaze that stops quickly is normal.

References

Baloh RW, Jen J. Neuro-ophthalmology. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 432.

Griggs RC, Jozefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 403.

Eye
The eye is the organ of sight, a nearly spherical hollow globe filled with fluids (humors). The outer layer or tunic (sclera, or white, and cornea) is fibrous and protective. The middle tunic layer (choroid, ciliary body and the iris) is vascular. The innermost layer (the retina) is nervous or sensory. The fluids in the eye are divided by the lens into the vitreous humor (behind the lens) and the aqueous humor (in front of the lens). The lens itself is flexible and suspended by ligaments which allow it to change shape to focus light on the retina, which is composed of sensory neurons.
Eye muscle test
The extraocular muscle function test is performed to evaluate any weakness, or other defect in the extraocular muscles which results in uncontrolled eye movements. The test involves moving the eyes in six different directions in space to evaluate the proper functioning of the extraocular muscles of the eyes.

Review Date: 1/21/2013
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.

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