title: Comparison of 4 methods for quantifying posterior capsule opacification.
abstract: OBJECTIVE
  To compare the results of posterior capsule opacification (PCO) quantification and the repeatability of a fully automated analysis system (Automated Quantification of After-Cataract [AQUA]) with that of 2 other quantification methods and subjective grading of PCO. A test set of digital retroillumination images of 100 eyes with PCO of varying degrees was used.
  
  
  METHODS
  Department of Ophthalmology, University of Vienna, Vienna, Austria.
  
  
  METHODS
  One hundred digital retroillumination images of eyes (100 patients) with PCO were selected to attain an even distribution from mild to severe cases. The images were evaluated by 4 methods: subjective grading by 4 experienced and 4 inexperienced examiners, the subjective Evaluation of Posterior Capsular Opacification (EPCO) system, posterior capsule opacification (POCO) software, and the AQUA system. Ten images were presented twice to assess the reproducibility of the analysis systems.
  
  
  RESULTS
  Subjective grading correlated best with the subjective EPCO system and the objective AQUA system (r = 0.94 and r = 0.93, respectively). The POCO system showed very early saturation and therefore a much weaker correlation (r = 0.73). The POCO scores reached the maximum of 100% in several minimal to mild PCO cases. The reproducibility of the AQUA software was perfect and that of the other analysis systems, comparably satisfactory.
  
  
  CONCLUSIONS
  The objective AQUA score correlated well with subjective methods including the EPCO system. The POCO system, which assesses PCO area, did not adequately describe PCO intensity and includes a subjective step in the analysis process. The AQUA system could become an important tool for randomized masked trials of PCO inhibition.
authors.affiliation: Department of Ophthalmology, University of Vienna, Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Findl
authors.forename: Wolf
authors.initials: W
authors.lastname: Buehl
authors.forename: Rupert
authors.initials: R
authors.lastname: Menapace
authors.forename: Michael
authors.initials: M
authors.lastname: Georgopoulos
authors.forename: Georg
authors.initials: G
authors.lastname: Rainer
authors.forename: Hannes
authors.initials: H
authors.lastname: Siegl
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kaider
authors.forename: Axel
authors.initials: A
authors.lastname: Pinz
mesh_terms: D002386:Cataract / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D006801:Humans; D015203:Reproducibility of Results; D012984:Software