title: Inter- and intra-observer variability in grading lesions of age-related maculopathy and macular degeneration.
abstract: OBJECTIVE
  To introduce a revised version of the grading system established by the International ARM Epidemiological Study Group for identifying and quantifying abnormalities of age-related maculopathy (ARM) and age-related degeneration (AMD) and to investigate its reliability, specifically the inter- and intra-observer variability.
  
  
  METHODS
  Fifty eyes of 25 patients with ARM or AMD in at least one eye were randomly selected from a large ongoing collection of clinical data and DNA in a tertiary referral UK population. Stereoscopic color fundus photographs were taken with a 30 degrees fundus camera and were centered on the macula. Presence and severity of fundus abnormalities in ARM and AMD were graded using a grid to define macular subfields and standard circles to define the size of lesions. Inter-observer variability was assessed by having three retinal specialists evaluate the color slides and intra-observer variability by re-grading the same set.
  
  
  RESULTS
  The inter-observer agreement for all subfields was fair to substantial for small hard drusen (70-89%; kappa=0.26-0.63) and intermediate soft drusen (76-94%; kappa=0.27-0.69). Agreement ranged between 87% and 100%, between 50% and 92%, and between 78% and 100% for larger drusen, the presence of hyperpigmentation, and the presence of hypopigmentation, respectively. Agreement was moderate to almost perfect for the presence of geographic atrophy (88-98%; kappa=0.60-0.95) and substantial to almost perfect for the presence of choroidal neovascularization (84-100%; kappa=0.62-1.00). The intra-observer variability for the grading of drusen characteristics and pigmentary changes was similar in magnitude, but slightly greater for features of advanced AMD.
  
  
  CONCLUSIONS
  Reproducibility was achieved using a revised version of the grading system established by the International ARM Epidemiological Study Group. This grading system may therefore be used for phenotyping of ARM and AMD.
authors.affiliation: Institute of Ophthalmology, Moorfields Eye Hospital, 162 City Road, EC1 V2PD, London, UK. hendrikscholl@hotmail.com
authors.forename: Hendrik P N
authors.initials: HP
authors.lastname: Scholl
authors.forename: Tunde
authors.initials: T
authors.lastname: Peto
authors.forename: Samantha
authors.initials: S
authors.lastname: Dandekar
authors.forename: Catey
authors.initials: C
authors.lastname: Bunce
authors.forename: Wen
authors.initials: W
authors.lastname: Xing
authors.forename: Sharon
authors.initials: S
authors.lastname: Jenkins
authors.forename: Alan C
authors.initials: AC
authors.lastname: Bird
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological; D005654:Fundus Oculi; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008268:Macular Degeneration / Q000145:classification* / Q000453:epidemiology; D015588:Observer Variation; D010781:Photography; D015203:Reproducibility of Results