title: The effectiveness of screening for diabetic retinopathy by digital imaging photography and technician ophthalmoscopy.
abstract: OBJECTIVE
  To evaluate the introduction of a community-based non-mydriatic and mydriatic digital photographic screening programme by measuring the sensitivity and specificity compared with a reference standard and assessing the added value of technician direct ophthalmoscopy.
  
  
  METHODS
  Study patients had one-field, non-mydriatic, 45 degrees digital imaging photography prior to mydriatic two-field digital imaging photography followed by technician ophthalmoscopy. Of these patients, 1549 were then examined by an experienced ophthalmologist using slit lamp biomicroscopy as a reference standard. The setting was general practices in Gloucestershire. Patients were selected by randomizing groups of patients (from within individual general practices) and 3611 patients were included in the study. Patients for reference standard examination were recruited from groups of patients on days when the ophthalmologist was able to attend. The main outcome measure was detection of referable diabetic retinopathy (DR) as defined by the Gloucestershire adaptation of the European Working Party guidelines.
  
  
  RESULTS
  For mydriatic digital photography, the sensitivity was 87.8%, specificity was 86.1% and technical failure rate was 3.7%. Technician ophthalmoscopy did not alter these figures. For non-mydriatic photography, the sensitivity was 86.0%, specificity was 76.7% and technical failure rate was 19.7%.
  
  
  CONCLUSIONS
  Two-field mydriatic digital photography is an effective method of screening for referable diabetic retinopathy. Non-mydriatic digital photography has an unacceptable technical failure rate and low specificity.
authors.affiliation: Gloucestershire Eye Unit, Cheltenham General Hospital, Cheltenham, Oxford Eye Hospital, Oxford, UK. peter.scanlon@egnhst.org.uk
authors.forename: P H
authors.initials: PH
authors.lastname: Scanlon
authors.forename: R
authors.initials: R
authors.lastname: Malhotra
authors.forename: G
authors.initials: G
authors.lastname: Thomas
authors.forename: C
authors.initials: C
authors.lastname: Foy
authors.forename: J N
authors.initials: JN
authors.lastname: Kirkpatrick
authors.forename: N
authors.initials: N
authors.lastname: Lewis-Barned
authors.forename: B
authors.initials: B
authors.lastname: Harney
authors.forename: S J
authors.initials: SJ
authors.lastname: Aldington
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D006801:Humans; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009184:Mydriatics; D009887:Ophthalmoscopy / Q000379:methods*; D010781:Photography / Q000379:methods*; D011237:Predictive Value of Tests; D014331:Tropicamide
chemical_list: D009184:Mydriatics; D014331:Tropicamide