Cover Test

The cover test is a powerful and simple probe into a person’s visual alignment status, or ‘posture’. Download the attached documents to learn how to do a simple cover test sequence.

You will learn how to

  • Tell the difference between an expected eye turn and one that might be a concern.
  • Describe the difference between an ‘eso’ posture and an ‘exo’ posture.
  • Distinguish between a strabismus and a ‘phoria’.
  • Distinguish between a constant and an intermittent strabismus.
  • And more.

These are not necessarily easy documents to follow, but the VIP Cover Test protocols are perhaps ‘easier’.

While there remains much more to the movement and alignment picture, the cover test combined with some basic visuomotor skills testing can reveal a lot about how a child is managing with vision skills. See your optometrist to learn more.

Learn more about testing visuomotor skills here:


Videos: The following clips include cover testing as part of a larger set of visuomotor and ocular alignment testing.

This first is an example of a slight ‘exo’ posture, or exophoria. Some would argue this is the ‘ideal posture’ for reading at near distance:

This next video is a similar case to the above, where there is an ‘exophoric’ posture. Again, this should not pose an obstacle to reading but is starting to verge on the high side of near phoria:

This final video shows a convergence insufficiency with an intermittent right exotropia, and very strong left exophoria. The patient can regain fusion when presented with a strong stimulus (end of the video). NB: There is no problem with the audio, it was simply omitted for most of the video.

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