title: Plus disease in retinopathy of prematurity: diagnostic impact of field of view.
abstract: OBJECTIVE
  To examine the impact of retinal field of view and magnification on interexpert reliability of plus disease diagnosis in retinopathy of prematurity.
  
  
  METHODS
  Fifteen wide-angle images from infants with retinopathy of prematurity were cropped and adjusted in magnification to create 2 additional image categories: medium angle (40°-50°) and narrow angle (20°-30°). These 45 images were uploaded to a Web-based system and interpreted independently by 13 experts of retinopathy of prematurity using a 3-level (plus, preplus, neither) and 2-level (plus, not plus) classification. Absolute agreement and kappa statistics were calculated to compare interexpert reliability.
  
  
  RESULTS
  In the 3-level classification, ≥ 70% experts agreed on the same diagnosis in 8 of the 15 wide-angle images (53%), but only in 3 of the 15 medium-angle (20%) and 3 of the 15 narrow-angle (20%) images. In the 2-level classification, ≥ 80% experts agreed on the same diagnosis in 11 of the 15 wide-angle images (73%), but only in 9 of the 15 medium-angle (60%) and 3 of the 15 narrow-angle (20%) images. Mean kappa of each expert compared with all other experts was 0.40 to 0.59 in 8 of 13 experts (62%) using wide-angle images, was 0 to 0.19 in 7 of 13 experts (54%) using medium-angle images, and was 0.20 to 0.39 in 9 of 13 experts (69%) using narrow-angle images.
  
  
  CONCLUSIONS
  Interexpert agreement in plus disease diagnosis in wide-angle images is higher than from medium-angle and narrow-angle images. Plus disease is defined using a narrow-angle standard published photograph, yet this study suggests that peripheral findings also contribute to diagnosis.
authors.affiliation: Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Rohini
authors.initials: R
authors.lastname: Rao
authors.forename: Nina J
authors.initials: NJ
authors.lastname: Jonsson
authors.forename: Camila
authors.initials: C
authors.lastname: Ventura
authors.forename: Rony
authors.initials: R
authors.lastname: Gelman
authors.forename: Martin A
authors.initials: MA
authors.lastname: Lindquist
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Casper
authors.forename: Michael F
authors.initials: MF
authors.lastname: Chiang
mesh_terms: D006801:Humans; D007231:Infant, Newborn; D015588:Observer Variation; D009887:Ophthalmoscopy / Q000379:methods*; D012171:Retinal Vessels / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000175:diagnosis*