Abstract
Purpose :
The aim of this study was to investigate volumetric characteristics of drusen during their development 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 of the individual eyes and the drusen volume for each ETDRS-field was segmented automatically by a custom-made software.
Results :
61 eyes were scanned regularly for a mean period of 36 months and up to 84 months. All eyes showed dynamic drusen volume development, with 45.9% of eyes showing regression of drusen volume of more than 15% at least once during the observation time. In the remaining 54.1%, a steady increase of the volume was observed over time. However, detailed analysis of the volume per ETDRS-field in those eyes showed a simultaneous regression and progression of drusen in 87.9% of eyes.
During observation time, 7 eyes conversed towards wet AMD and 5 eyes towards geographic atrophy (GA). As expected, in each eye the advent of GA was preceded by an imminent regression of the total drusen volume. The development of CNV was not as distinct. In 4 eyes, a preceding general regression of drusen volume was observed, with regression in the ETDRS-field where CNV later occurred; however, in the other 3 eyes, a considerable increase of drusen volume at the location of the later occurring CNV was observed.
Conclusions :
The majority of eyes in early AMD show a dynamic drusen modeling with progression as well as regression of drusen volume occurring simultaneously at different locations within the same retina. In most cases, small distinct regression events are overridden by a much more substantial progression, resulting in a total increase of drusen volume that can be observed clinically and that is a known risk factor for progression of disease. The development of individual drusen preceding GA or CNV remains an interesting field of research.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.