title: Comparison of stereoscopic digital imaging and slide film photography in the identification of macular degeneration.
abstract: BACKGROUND
  This study compared the sensitivity and specificity of stereoscopic digital photography of the retina through a dilated pupil with a 45 degrees nonmydriatic camera and Joint Photographic Experts Group (JPEG) compression of the images with the sensitivity and specificity of 35-mm slide film photography in the identification of age-related macular degeneration (AMD).
  
  
  METHODS
  Consecutive patients with a diagnosis of AMD were enrolled. Stereoscopic retinal images of the disc, macula and temporal macula were captured with a digital 45 degrees nonmydriatic camera (then compressed into JPEG format) and with a standard fundus camera and slide film. A single retinal specialist graded both image formats in masked fashion, at least 1 month apart, using a modified Age-Related Eye Disease Study (AREDS) severity scale. The digital images were displayed on a monitor and viewed with the use of liquid crystal display shutter glasses and stereo imaging software. The film images were mounted on a light box and graded with the use of a stereoviewer. Primary outcome measures included the presence or absence of AMD pathological features. Positive and negative predictive values (PPVs and NPVs), sensitivity, specificity and weighted kappaw statistics were calculated.
  
  
  RESULTS
  We photographed 203 eyes (of 103 patients) with both digital and slide film cameras. Correlation of the 2 image formats was substantial in identifying AREDS level 3a or greater (kappaw=0.64, standard error=0.08, PPV=0.95, NPV=0.66, sensitivity=0.93, specificity=0.74) and excellent in identifying level 4b or greater (kappaw=0.83, standard error=0.05, PPV=0.81, NPV=0.98, sensitivity=0.94, specificity=0.94).
  
  
  CONCLUSIONS
  High-resolution stereoscopic, mydriatic, 45 degrees digital images captured with a nonmydriatic camera and JPEG compressed correlate well with stereoscopic slide film photographs in the identification of moderate to advanced AMD (AREDS level 3a or greater).
authors.affiliation: Department of Ophthalmology, Royal Alexandra Hospital, University of Alberta, Edmonton, Canada.
authors.forename: Riz
authors.initials: R
authors.lastname: Somani
authors.forename: Matt
authors.initials: M
authors.lastname: Tennant
authors.forename: Chris
authors.initials: C
authors.lastname: Rudnisky
authors.forename: Ezekiel
authors.initials: E
authors.lastname: Weis
authors.forename: Andrew
authors.initials: A
authors.lastname: Ting
authors.forename: Jayson
authors.initials: J
authors.lastname: Eppler
authors.forename: Mark
authors.initials: M
authors.lastname: Greve
authors.forename: Brad
authors.initials: B
authors.lastname: Hinz
authors.forename: Alex
authors.initials: A
authors.lastname: de Leon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D008268:Macular Degeneration / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*