A patient with alternating exotropia

Left secondary exotropia from ROP

Exotropia correctable with minus lenses. The minus 
lens stimulate accommodation and hence convergence.

Exotropia is less common than esotropia in the ocular motility examination. However, it is commonly seen in patients with 
poor vision from varied causes such as chronic retinal detachment or optic neuropathy. Most cases seen in the examination
will either be intermittent exotropia or consecutive exotropia from over-correction of esotropia.

In intermittent exotropia, three types may be seen.

1) Divergence excess
On cover/uncover test for near fixation, the eye is orthophoric but on alternating cover test, there is a large exophoria which recovers slowly. With distant fixation, the eye shows exotropia which becomes straight after one or two blinks. The exotropia increases on alternating cover test.

2) Convergence weakness
In this condition, the exotropia is worse with near fixation.

3) Basic
The magnitude of the exotropia is the same for near and distant fixation.

Other examination:
  • mention that you would like to perform ocular motility. Patients usually has a V pattern ie. the exotropia increases 

  • on upgaze
  • if the patient has constant exotropia mention that you would like to test the visual acuity. The exotropia may be 

  • secondary to poor vision
  • in patients with evidence of DVD (dissociated vertical deviation) during the cover/uncover test consider the 

  • possibility of consecutive exotropia and examine the eye for previous squint surgery (conjunctival scar).


1. How would you manage a patient with intermittent exotropia?

2. What is meant by secondary exotropia and how would you manage the patient?

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