Abstract
Purpose :
The aim of this study was to identify the clinically relevant morphologic risk factors at the level of the retina and retinal pigment epithelium (RPE) during disease progression in early and intermediate age-related macular degeneration (AMD).
Methods :
38 patients with early or intermediate AMD were scanned using Spectralis SD-OCT (scanning area 20°x20°, volume scan 1024x97) in a regular follow-up scheme of every three months for at least one year. The standard ETDRS grid was centered on the fovea and the drusen volume for each ETDRS-field was automatically segmented by a software. Three expert graders reviewed the individual B-scans. The presence of pseudodrusen, RPE-migration, inhomogeneous content of drusen and vortexing of the internal retinal layers within each ETDRS-field was noted, and the integrity of the RPE-layer as well as of the ELM and IS-OS-layer was evaluated.
Results :
61 eyes were observed regularly for a mean period of 36 months and up to 84 months. Progression of drusen volume was observed in all eyes, as well as spontaneous regression, often occurring simultaneously at different locations in the same eye. During follow up, 7 eyes progressed towards CNV and 5 towards geographic atrophy (GA). In eyes where disease progressed, pseudodrusen, RPE-migration, inhomogeneous drusen content and vortexing were present significantly more often than in eyes where disease remained stable, a finding that was even more profound when analyzing the same ETDRS-field where CNV or GA later occurs (p<0.001). Likewise, discontinuities within the RPE and IS-OS line were significantly more frequent in eyes that progressed (p<0.001). Drusen regression is a frequent event, with 93.4% of eyes showing single drusen volume regressions at least once during observation time. However, no morphologic characteristic seems to precede a regression event; only an inhomogeneous drusen content is a slight, but significant protective factor (p<0.05).
Conclusions :
Characteristic morphological features have a significant impact on disease progression from early to advanced AMD. Drusen development was shown to be a dynamic and focally enhanced process, and detailed analysis of the interdependency of risk factors might lead to a more comprehensive understanding of pathomechanisms in AMD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.