title: Relationship between dry eye symptoms and pain sensitivity.
abstract: OBJECTIVE
  Dry eye disease (DED) is common, but little is known about factors contributing to symptoms of dry eye, given the poor correlation between these symptoms and objective signs at the ocular surface.
  
  
  OBJECTIVE
  To explore whether pain sensitivity plays a role in patients' experience of DED symptoms.
  
  
  METHODS
  A population-based cross-sectional study of 1635 female twin volunteers, aged 20 to 83 years, from the TwinsUK adult registry.
  
  
  METHODS
  Dry eye disease was diagnosed if participants had at least 1 of the following: (1) a diagnosis of DED by a clinician, (2) the prescription of artificial tears, and/or (3) symptoms of dry eyes for at least 3 months. A subset of 689 women completed the Ocular Surface Disease Index (OSDI) questionnaire. Quantitative sensory testing using heat stimulus on the forearm was used to assess pain sensitivity (heat pain threshold [HPT]) and pain tolerance (heat pain suprathreshold [HPST]).
  
  
  RESULTS
  Of the 1622 participants included, 438 (27.0%) were categorized as having DED. Women with DED showed a significantly lower HPT (P = .03) and HPST (P = .003)--and hence had higher pain sensitivity--than those without DED. A strong significant association between the presence of pain symptoms on the OSDI and the HPT and HPST was found (P = .008 for the HPT and P = .003 for the HPST). In addition, participants with an HPT below the median had DED pain symptoms almost twice as often as those with an HPT above the median (31.2% vs 20.5%; odds ratio, 1.76; 95% CI, 1.15-2.71; P = .01).
  
  
  CONCLUSIONS
  High pain sensitivity and low pain tolerance are associated with symptoms of DED, adding to previous associations of the severity of tear insufficiency, cell damage, and psychological factors. Management of DED symptoms is complex, and physicians need to consider the holistic picture, rather than simply treating ocular signs.
authors.affiliation: Department of Twin Research & Genetic Epidemiology, King's College London, St Thomas' Hospital, Waterloo, London, England2Department of Ophthalmology & Epidemiology, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: Jelle
authors.initials: J
authors.lastname: Vehof
authors.forename: Diana
authors.initials: D
authors.lastname: Kozareva
authors.forename: Pirro G
authors.initials: PG
authors.lastname: Hysi
authors.forename: Juliette
authors.initials: J
authors.lastname: Harris
authors.forename: Ayrun
authors.initials: A
authors.lastname: Nessa
authors.forename: Frances K
authors.initials: FK
authors.lastname: Williams
authors.forename: David L H
authors.initials: DL
authors.lastname: Bennett
authors.forename: Steve B
authors.initials: SB
authors.lastname: McMahon
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Fahy
authors.forename: Kenan
authors.initials: K
authors.lastname: Direk
authors.forename: Tim D
authors.initials: TD
authors.lastname: Spector
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hammond
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006941:Hyperesthesia / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D017288:Pain Threshold / Q000502:physiology; D011795:Surveys and Questionnaires; D014427:Twins; D055815:Young Adult