title: Relationship between difficulty in performing daily activities and clinical measures of visual function in patients with retinitis pigmentosa.
abstract: OBJECTIVE
  To assess the level of perceived difficulty experienced by patients with retinitis pigmentosa (RP) in the performance of everyday activities and to determine the correlation between patients' self-reported difficulty and clinical measures of visual function.
  
  
  METHODS
  One hundred sixty-seven patients with typical RP and Usher syndrome type 2, with a wide range of disease severity, rated their difficulty in the performance of 33 activities. We obtained data on visual acuity and visual field area for all patients, and electroretinogram (ERG) recordings on a subgroup of 49 of these patients. Results from the questionnaire were analyzed with factor analysis, and patients' self-reports were compared with their clinical data using correlational analyses and multiple regression.
  
  
  RESULTS
  The patients' questionnaire responses clustered into 6 factors: activities involving central vision, miscellaneous activities (no discernible common factor), activities related to mobility, driving, negotiating steps, and eating meals. Of the clinical tests, visual acuity was most strongly related to the patients' ratings of their difficulty in performance. Visual field area also was related to patients' self-assessments but not as strongly as visual acuity. Because visual field area and the ERG measures were correlated, adding ERG information did not improve predictability.
  
  
  CONCLUSIONS
  In patients with RP, perceived difficulty in performing common tasks was most strongly related to level of visual acuity and visual fields. Although certain ERG amplitude measures did show positive correlations with some self-reported activities, overall, the ERG amplitude measures showed the least relationship with patients' self-reports. Our results provide insight into RP patients' perceived difficulties in performing everyday activities and the clinical measures of visual function that most highly correlate with these difficulties.
authors.affiliation: Department of Ophthalmology and Visual Sciences, UIC Eye Center, University of Illinois at Chicago, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Szlyk
authors.forename: G A
authors.initials: GA
authors.lastname: Fishman
authors.forename: K R
authors.initials: KR
authors.lastname: Alexander
authors.forename: B I
authors.initials: BI
authors.lastname: Revelins
authors.forename: D J
authors.initials: DJ
authors.lastname: Derlacki
authors.forename: R J
authors.initials: RJ
authors.lastname: Anderson
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003638:Deafness / Q000151:congenital; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000503:physiopathology; D012174:Retinitis Pigmentosa / Q000503:physiopathology*; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*