Headache caused by latent or persistent strabismus, usually occurring after prolonged visual tasks.
A. Frontal headache fulfilling criterion C
B. Strabismus has been identified, with at least one of the following symptoms:
1. blurred vision
3. difficulty switching from near to far focus and/or vice versa
C. Evidence of causation demonstrated by at least two of the following:
1. headache has developed in temporal relation to the onset of the strabismus, or led to its discovery
2. headache has significantly improved after correction of the strabismus
3. headache is aggravated by sustained visual tasks
4. headache is alleviated by closing one eye and/or discontinuation of the visual task
D. Not better accounted for by another ICHD-3 diagnosis.
Most patients with 11.3.3 Headache attributed to heterophoria or heterotropia will seek advice from an ophthalmologist. There is little evidence for this cause of headache other than a number of supportive cases.