Abstract

SA.23.04

Grading of age-related macular degeneration – comparison between color fundus photography, angiography and optical coherence tomography

Sandra Liakopoulos1, Tina Ristau1, N. F. Mokwa1, P. A. Keane2, Srinivas R. Sadda2, Bernd Kirchhof1
1Cologne Image Reading Center (CIRCL), Center for Ophthalmology, University of Cologne, Germany; 2Doheny Image Reading Center (DIRC), Doheny Eye Institute, Los Angeles, CA

Objective: Gold standard for the grading of age-related macular degeneration (AMD) has been color fundus photography. Fluorescein angiography (FA) and optical coherence tomography (OCT) however are increasingly used for the grading of eyes with AMD, especially for follow-up studies. Sensitivity and specificity of those three instruments for the detection of various pathological features in AMD have been assessed.
Methods: In this retrospective study, 120 eyes with early or late AMD or no signs for AMD were included. Control eyes were allowed to show signs for chorioretinal diseases other than AMD. Color fundus pictures, FAs and OCT volume-scans (Spectralis, 37 parallel B-scans, 20°x15°, ART mode on with 20 images averaged) have been collected for all patients. All images were graded independently by two certified Reading Center graders and blinded with respect to the other imaging modalities. Pathological features as drusen, atrophy of the retinal pigment epithelium (RPE) and signs for active or previous choroidal neovascularisation (CNV) were detected. Eyes were categorized into 5 different stages: 1- no AMD, 2- early AMD, 3- intermediate AMD, 4- geographic atrophy and 5- neovascular AMD. A feature was considered present if it was visible with at least one of the imaging modalities.
Results: Color fundus photography showed the best sensitivity of all three instruments for detecting signs for AMD as drusen or RPE changes, however the lowest sensitivity for detecting CNV. In contrast, all CNV lesions have been detected by FA and OCT. There were differences between FA and OCT images however regarding the grading of CNV activity. One possible explanation may be that FA and OCT provide different types of information. While FA images visualize the distribution of fluorescein molecules over time, OCT scans demonstrate the arrangement of different layers, spaces or features within or below the retina. However, small lesions can remain undetected with OCT if they are located between two scans.
Conclusions: We could validate fundus photography as the gold standard for the detection of features related to AMD such as drusen and RPE changes. FA and OCT however allowed identification of CNV some cases, in which fundus photography failed to reveal signs for CNV. In contrast to FA, OCT is a non-invasive tool, which can be used even in control patients without any ethical concerns. Further studies are needed to define the role of OCT scans besides fundus photography and FA images for grading and staging of AMD in clinical trials.

Copyright: 2009 Porstmann Kongresse GmbH. All rights reserved. Impressum, Disclaimer.