title: Validation of patient symptom diary in acute posterior vitreous detachment.
abstract: OBJECTIVE
  The purpose of the study is to determine the validity of an original patient symptom diary in recording symptoms of posterior vitreous detachment (PVD).
  
  
  METHODS
  In this prospective cohort study, all patients presenting to the Hotel Dieu hospital emergency eye clinic between September 2008 and July 2009 diagnosed with acute PVD were offered enrollment in the study. Patients were given the Queen's University posterior vitreous detachment patient diary at the initial visit after detailed eye examination, assessment of risk factors for retinal tears and detachments and a thorough explanation of their presenting complaints to record their symptoms related to PVD. At a random point during their six-week follow up, the patients were verbally asked the same questions being recorded in the diary over the phone. At the six-week follow up visit, the diaries were collected and the verbal results were compared with the written results.
  
  
  RESULTS
  There was substantial to near perfect agreement between the verbal questions and written answers. Cohen's kappa scores for flash frequency, flash intensity, floater frequency, and floater type were 0.6229, 0.6389, 0.6495, and 0.8603, respectively.
  
  
  CONCLUSIONS
  The Queen's University posterior vitreous detachment patient diary is a useful tool for investigating the quantity, quality and change in symptoms of patients presenting with PVD in the first 6 weeks of initial presentation.
authors: Queen's University Ophthalmology, Kingston, Ontario, Canada.
authors: Kelly D
authors: KD
authors: Schweitzer
authors: Amaka A
authors: AA
authors: Eneh
authors: Jonathan
authors: J
authors: Hurst
authors: Mark D
authors: MD
authors: Bona
authors: Karim J
authors: KJ
authors: Rahim
authors: Marwan
authors: M
authors: Abouammoh
authors: Sanjay
authors: S
authors: Sharma
keywords: Cohen’s kappa; Inter-rater agreement statistics; Krippendorff’s alpha; Posterior vitreous detachment; Symptom diary; Validation
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