Abstract
Abstract: :
Purpose: We have previously developed a non-proprietary program based on Adobe Photoshop TM Actions (Adobe Systems Inc., San Jose, CA) to measure drusen area in digitized fundus photographs. In this study, we assessed the suitability of this software for measuring drusen area in a drusen reduction randomized controlled trial. Methods: Consecutive fluorescein angiograms in patients with a diagnosis of age-related macular degeneration (AMD) taken in King’s College Hospital between April 1999 and November 2002 were reviewed. Patients who had choroidal neovascularization in one eye and significant drusen in the other eye were included. The presence of significant drusen was defined as more than 5 large drusen or more than 20 small drusen in the macular area. Color digital fundus images of these patients were analyzed to determine whether they were suitable to be assessed by this software based on its previously determined limitations. Results: A total of 100 images were analyzed. Of these, 79 were found to be suitable for analysis by the software. Of the 21 considered unsuitable, 13 had extensive mixed retinal pigment epithelial (RPE) changes limiting drusen identification, 5 had a significant number of reticular drusen, which are poorly identified by the software, and 3 had multiple small areas of RPE atrophy, which are difficult to distinguish from drusen. These three factors were found to be the main limitations in quantifying drusen area using this software. Conclusion: Manual quantification of drusen load is time consuming. This study demonstrates that this semi-automatic software has the potential to assess the change of drusen area in the majority of high-risk patients with age-related maculopathy in a drusen reduction trial.
Keywords: age-related macular degeneration • drusen • imaging/image analysis: clinical