Article
Configuration and topography of geographic atrophy secondary to age-related macular degeneration
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Published: | June 15, 2011 |
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Purpose: To determine the topographic distribution and configuration of atrophic patches in patients with geographic atrophy (GA) secondary to age-related macular degeneration.
Methods: Fundus autofluorescence images of 413 GA eyes of 413 patients were analyzed. The macula was divided in ten different sector using a grid in order to determine the local presence of GA. In addition, the prevalence and configuration of peripapillary atrophy (PPA) was evaluated. Determination of linear dimension and regression of the buffer zone (shortest distance between PPA and central atrophy) was performed in a subset of eyes (n=42, 18 months follow-up).
Results: Sector analysis showed atrophy involvement within 600 microns from the foveal center to be present in 95% of eyes. The parafovea (circle of 1800 microns) showed GA more frequently (99%) when compared to the outer macula (circle of 3600 microns; 80%). A total of 357 of 413 (86%) eyes showed additional PPA that was non-confluent to central GA in 328 eyes. In the 4 out of 42 eyes that converted into confluent atrophy within 18 months, the mean puffer zone with 147 µm (Range 79–175 µm) was significantly smaller in comparison to the 38 eyes (Mean puffer zone 1481 µm, range 158–3117 µm) that stayed non-confluent (p<0.0002).
Conclusions: The results indicate an eccentricity-dependent development and an asymmetric topographic distribution of GA in relation to the foveal center. The additional presence of PPA is a common phenomenon in GA. However, PPA is seldom confluent to central atrophy. Refined analyses of topographic distribution and directional spread of GA is important both for the understanding of the natural history of the disease as well as for the design and outcome measures for interventional clinical trials.