title: Development of a forced choice photographic questionnaire for photic phenomena and its testing - repeatability, reliability and validity.
abstract: OBJECTIVE
  To design, develop and test a system for analysis of photic phenomena.
  
  
  METHODS
  Extensive background research, patient interviews and theoretical studies led to development of a set of photographic images resembling photic phenomena experienced by patients. These photographic images were processed and digitally altered to create scales of severity for each photic phenomenon in which patients indicated their severity of symptoms by choice of image. The system was tested for stability and validity.
  
  
  RESULTS
  The system showed excellent repeatability and reliability. Face, content, criterion and construct validity were all found to be acceptable.
  
  
  CONCLUSIONS
  The photographic images of photic phenomena analyser is an acceptable, validated measure for the assessment of photic phenomena, in both pseudophakic patients and those with cataract.
authors.affiliation: Princess Alexandra Eye Pavilion, Edinburgh, UK. TAslam@aol.com
authors.forename: T M
authors.initials: TM
authors.lastname: Aslam
authors.forename: B
authors.initials: B
authors.lastname: Dhillon
authors.forename: V R
authors.initials: VR
authors.lastname: Tallentire
authors.forename: N
authors.initials: N
authors.lastname: Patton
authors.forename: P
authors.initials: P
authors.lastname: Aspinal
mesh_terms: D002755:Choice Behavior; D019466:Glare; D006801:Humans; D008027:Light; D010781:Photography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000175:diagnosis*