title: The role of retinopathy distribution and other lesion types for the definition of examination intervals during screening for diabetic retinopathy.
abstract: OBJECTIVE
  It has previously been shown that the intervals between screening examinations for diabetic retinopathy can be optimized by including individual risk factors for the development of the disease in the risk assessment. However, in some cases, the risk model calculating the screening interval may recommend a different interval than an experienced clinician. The purpose of this study was to evaluate the influence of factors unrelated to diabetic retinopathy and the distribution of lesions for discrepancies between decisions made by the clinician and the risk model.
  
  
  METHODS
  Therefore, fundus photographs from 90 screening examinations where the recommendations of the clinician and a risk model had been discrepant were evaluated. Forty features were defined to describe the type and location of the lesions, and classification and ranking techniques were used to assess whether the features could predict the discrepancy between the grader and the risk model.
  
  
  RESULTS
  Suspicion of tumours, retinal degeneration and vascular diseases other than diabetic retinopathy could explain why the clinician recommended shorter examination intervals than the model. Additionally, the regional distribution of microaneurysms/dot haemorrhages was important for defining a photograph as belonging to the group where both the clinician and the risk model had recommended a short screening interval as opposed to the other decision alternatives.
  
  
  CONCLUSIONS
  Features unrelated to diabetic retinopathy and the regional distribution of retinal lesions may affect the recommendation of the examination interval during screening for diabetic retinopathy. The development of automated computerized algorithms for extracting information about the type and location of retinal lesions could be expected to further optimize examination intervals during screening for diabetic retinopathy.
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark.
authors.forename: Giovanni
authors.identifier: http://orcid.org/0000-0002-0900-4847
authors.initials: G
authors.lastname: Ometto
authors.affiliation: Section for Biostatistics, Department of Public Health, University of Aarhus, Aarhus C, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Erlandsen
authors.affiliation: School of Computer Science, University of Lincoln, Lincoln, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hunter
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark.
authors.forename: Toke
authors.initials: T
authors.lastname: Bek
mesh_terms: D000328:Adult; D000465:Algorithms; D003718:Denmark / Q000453:epidemiology; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015994:Incidence; D008297:Male; D008403:Mass Screening / Q000379:methods*; D010781:Photography / Q000379:methods*; D012160:Retina / Q000473:pathology*; D012189:Retrospective Studies
keywords: decision model; diabetic retinopathy; grading; screening