title: The association of headache and monocular blur effect in a clinical population.
abstract: OBJECTIVE
  Because some headaches are known to be associated with errors in binocular vision and because monocular visual acuity has been observed to change in different directions of gaze during binocular viewing, a study was designed to see if headaches were associated with this phenomenon.
  
  
  METHODS
  This cross-sectional study cross-classifies each subject in a sample selected in consecutive order from an optometric practice by whether or not the patient has at least three headaches per month and by whether or not the patient has the monocular blur effect. Each of the two examiners conducted this cross-classification separately on the same sample. The laterality of the headache and the side which exhibited the monocular blur effect were also noted.
  
  
  RESULTS
  The resulting two-way tables are presented along with the results of the chi 2 tests. The results are statistically significant.
  
  
  CONCLUSIONS
  It appears that a relation exists between the occurrence of headache and binocular vision anomalies associated with the action of the eye muscles. The extraocular muscles and relevant neurological and vascular physiology are discussed as they relate to headache.
authors.forename: D F
authors.initials: DF
authors.lastname: Sucher
mesh_terms: D003430:Cross-Sectional Studies; D007839:Functional Laterality; D006261:Headache / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D015835:Ocular Motility Disorders / Q000150:complications; D009801:Oculomotor Muscles / Q000502:physiology; D014786:Vision Disorders / Q000150:complications; D015357:Vision Disparity / Q000502:physiology*; D015349:Vision, Monocular / Q000502:physiology*