title: Objective quantification of posterior capsule opacification after cataract surgery, with optical coherence tomography.
abstract: OBJECTIVE
  To evaluate posterior capsule opacification (PCO) in humans after cataract surgery with intraocular lens (IOL) implantation, by using optical coherence tomography (OCT-1).
  
  
  METHODS
  Sixty-six eyes with PCO and 20 eyes with a normal posterior capsule were analyzed. A 3-mm-long horizontal scan of the posterior capsule was obtained. Measurements at three points and their average were recorded. Intraoperator and interoperator reliabilities were assessed. Investigated was peak intensity (PI) and posterior capsule thickening (PCT), with PCT indicating the distance between two reflectivity spikes, with an approximate axial resolution of 10 microm. Results were compared with visual acuity (VA) and PCO type.
  
  
  RESULTS
  Intraoperator reliability was 0.59 and 0.97 for average PI and PCT, respectively. The interoperator concordance correlation coefficient was 0.70 and 0.82 for average PI and PCT, respectively. Median (interquartile range) intensities of the reflectivity spike were 16.88 (dB) (range, 12.88-20.41) and 11.9 (8.58-14.28), respectively, in the PCO and control eyes (P = 0.001). PCT was found in PCO eyes (median: 86.13 microm; range, 46.33-115.33), whereas no second spike appeared in control eyes (P = 0.001). The area under the receiver operating characteristic curve of the average PCT for differentiating pearl-type from fibrosis-type PCO was 0.87 (P = 0.001). For a cutoff point of 55.3 microm, the sensitivity was 97.5%, and the specificity was 69%. Worse VA correlated significantly only with larger PCT (r(o) = 0.66; P = 0.01).
  
  
  CONCLUSIONS
  OCT-1 appears useful to quantitate PCO. In addition, this system seems to discriminate between different types of PCO. PCT may be a previously unrecognized factor in VA degradation.
authors.affiliation: Department of Ophthalmology, Clínica Universitaria, Facultad de Medicina, Universidad de Navarra, Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Moreno-Montañés
authors.forename: Aurora
authors.initials: A
authors.lastname: Alvarez
authors.forename: Miguel J
authors.initials: MJ
authors.lastname: Maldonado
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002386:Cataract / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005355:Fibrosis; D006801:Humans; D007903:Lens Capsule, Crystalline / Q000473:pathology*; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D018918:Phacoemulsification; D011183:Postoperative Complications; D012372:ROC Curve; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity