Local Progression Kinetics of Geographic Atrophy in Age-Related Macular Degeneration Are Associated With Atrophy Border Morphology.

Purpose To assess the impact of distinct atrophy border characteristics based on spectral-domain optical coherence tomography (SD-OCT) imaging on local atrophy progression. Methods Patients with geographic atrophy (GA) secondary to AMD were recruited in the context of the Longitudinal Fundus Autofluorescence in Age-related Macular Degeneration and Directional Spread in Geographic Atrophy studies (NCT00393692, NCT02051998). Horizontal and vertical SD-OCT scans were acquired at sequential visits using a device allowing for anatomically accurate registration of follow-up to baseline scans. For quantification of local atrophy progression, the lateral spread of GA (LSGA) was measured. Further, border types were independently graded. Comparison of LSGA between the different border types was performed using linear mixed-effects models. Results Seventy-two eyes of 49 patients (27 female) aged 74.0 years (Inter quartile range [IQR], 68.1-79.0) were included into this analysis. A total of 258 border sections were analyzed longitudinally over a median period of 1.2 years (IQR, 0.9-1.6). At baseline, 17.1% borders were classified as 'regular', 47.7% as 'irregular', and 35.3% as 'splitting'. Sixty-two percent of the eyes exhibited more than one border type. LSGA was slowest in 'regular' borders (62.85 ± 25.29 μm/y), followed by 'irregular' borders (91.15 ± 15.05 μm/y) and fastest in 'splitting' borders (183.15 ± 18.17 μm/y). Differences between the 'splitting' and each other border type were statistically significant (P < 0.001). Conclusions The results indicate that SD-OCT-based assessment of local GA border morphology can serve as a predictor for local atrophy progression. These observations help to better understand the natural history and potential pathogenetic factors of GA development and progression.