Computerised PCO Evaluation with EPCO:
A Reliability Study
Ch. Nimsgern, M.R. Tetz, G.U. Auffarth
Introduction: Posterior capsule opacificaten (PCO) is a common complication following modern cataract surgery with lOL implantation. It appears in 10-50% according to literature. One reason for this wide range is the different PCO definition. We developed an easy-to-use software called EPCO (Evaluation of PCO), that is based exclusively on morphological assessment of secondary cataract. ln this study reliability af this system is examined.
Method: Using a modified Zeissâ slitlamp standardized retroillumination photographs were taken digitally. On a personal computer the density of PCO is interactively scored on a scale from 0 to 4, and multiplied by the area involved. In order to evaluate the reliability of the EPCO system we examined in experiment A the interindividual reliability. Three observers analyzed ten identical clinical PCO images. Experiment B focused on intraindividual reliability with one observer scoring the same image on ten consecutive days. In experiment C different photographs of the same eye were evaluated.
Results: Morphological PCO-scores were found to be very reliable. With PCO values ranging from 0 to 4, the interindividual reliability revealed standard deviations between 0.2 and 0.4. The intraindividual reliability showed standard deviations between 0.1 and 0.4. The standard deviation was 0.2 when scoring different photographs of the same eye.
Conclusion: This method allows evaluation of large numbers of eyes with PCO whereby it is faet and easy to handle. lt reveals good reliability and tolerable investigator-dependent variations. Systematic errors can be largely excluded by using a standardized photographic setup and trained examiners.
Department of Ophthalmology, INF 400, 69120 Heidelberg, Germany