title: Item by item analysis strategy of the relationship between symptoms and signs in early dry eye.
abstract: OBJECTIVE
  The present study aimed at analyzing the relationship between several particular symptoms, risk factors or global questionnaire scores and some tear clinical signs in early dry eye patients.
  
  
  METHODS
  A total of 77 volunteers were enrolled in the study without any prior classification, although patients with severe dry eye were excluded. Two questionnaires were used to assess ocular symptoms and risk factors, and clinical tear signs were evaluated with four tests (osmolarity, ferning, break-up time and the phenol red thread test). Multiple linear regression analysis was performed to determine the relative predictive value of each particular ocular symptom and risk factor, for each clinical sign. This analysis was repeated using symptoms and risk factors global scores.
  
  
  RESULTS
  The symptom "eyes stuck shut in the morning" was the only predictor variable for the sign "ferning crystallization" (R = 0.228, p < 0.05) and "dryness" for "break-up time" (R = -0.315, p < 0.01). "Burning sensation" and "computer use for more than 3 h" were predictor variables for "tear osmolarity" (R = 0.342, p < 0.01), while "itching" and "female gender" were found to predict the outcomes of the "phenol red thread test" (R = -0.462, p < 0.05). Global questionnaire scores were not found to predict any tear clinical sign.
  
  
  CONCLUSIONS
  The present findings support the informative value of exploring the associations between clinical signs, ocular symptoms and risk factors by following an item by item strategy rather than opting for global questionnaire scores.
authors.affiliation: Ocular Surface Research Group, Optics and Optometry Department, Universitat Politècnica de Catalunya, Terrassa, Catalonia, Spain. julio@oo.upc.edu
authors.forename: Gemma
authors.initials: G
authors.lastname: Julio
authors.forename: Sara
authors.initials: S
authors.lastname: Lluch
authors.forename: Genís
authors.initials: G
authors.lastname: Cardona
authors.forename: Albert
authors.initials: A
authors.lastname: Fornieles
authors.forename: Dolores
authors.initials: D
authors.lastname: Merindano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000378:metabolism / Q000473:pathology*; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000378:metabolism; D042241:Early Diagnosis; D005260:Female; D019793:Fluorescein / Q000008:administration & dosage; D005456:Fluorescent Dyes / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008858:Microscopy, Phase-Contrast; D008875:Middle Aged; D009883:Ophthalmic Solutions; D009994:Osmolar Concentration; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013666:Tears / Q000737:chemistry*; D013997:Time Factors; D055815:Young Adult
chemical_list: D005456:Fluorescent Dyes; D009883:Ophthalmic Solutions; D019793:Fluorescein