title: The correlation between migraine headache and refractive errors.
abstract: OBJECTIVE
  A literature review reveals historical references to an association between migraine headache and refractive errors, but a lack of scientific evidence relating to these claims.
  
  
  METHODS
  In a masked case-controlled study, we investigated the four aspects of refractive errors that have been implicated in the literature as correlated with migraine: spherical refractive error, astigmatic refractive error, anisometropia, and uncorrected ametropia. We also compared the calculated scalar value of refractive error, aided and unaided visual acuity, and spectacle use in migraine and control groups. We then investigated the relationship between refractive components and key migraine headache variables.
  
  
  RESULTS
  Compared with the control group, the migraine group had higher degrees of astigmatic components of refractive error assessed both objectively (C, p = 0.01; C(0), p = 0.01; C(45), p = 0.05) and subjectively (C, p = 0.03; C(0), p = 0.03; C(45), p = 0.05), uncorrected astigmatic components of refractive error (C(0), p = 0.02; C(45), p = 0.04), and anisometropia (p = 0.06).
  
  
  CONCLUSIONS
  Perhaps the historical literature is indeed correct that low degrees of astigmatism and anisometropia are relevant in migraine. Our most significant finding was of higher degrees of astigmatism in the migraine group. This study does indicate that people who experience migraine headaches should attend their optometrist regularly to ensure that their refractive errors are appropriately corrected.
authors.affiliation: The Neville Chappell Research Clinic, The Institute of Optometry, London, UK. dharle@ioo.org.uk
authors.forename: Deacon E
authors.initials: DE
authors.lastname: Harle
authors.forename: Bruce J W
authors.initials: BJ
authors.lastname: Evans
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000209:etiology* / Q000517:prevention & control; D011379:Prognosis; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000150:complications* / Q000534:rehabilitation; D012720:Severity of Illness Index; D014792:Visual Acuity