Cover Test
February 4th, 2020
Overview
The cover test is a useful test for determining the presence of a tropia (constant, or manifest strabismus).
In strabismus, there is a normal eye that tends to fixate on objects, an an affected eye that is deviated slightly outward, inward, upward or downward.
How to Perform
- Ask the patient to look at an object such as the wall in front of them. Cover one eye using a hand or an opaque cover for a few seconds, and look for movement of the non-covered eye.
Interpretation
- Non-covered eye does not move - means that no strabismus is present, or the non-covered eye is the normal eye
- Non-covered eye moves inward - suggests an exotropia of the non-covered eye (i.e. that it is angulated outward)
- Non-covered eye moves outward - suggests an esotropia of the non-covered eye (i.e. that it is angulated inward)
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