Geographic atrophy in Korean patients with dry age-related macular degeneration: incidence, phenotypes, and progression.

OBJECTIVE

To evaluate the characteristics of geographic atrophy (GA) in Korean patients, including incidence, phenotypes, progression patterns, and factors associated with progression rates.

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

Korean patients with intermediate and advanced (prevalent GA) dry AMD, followed for ≥3 years.

METHODS

GA incidence was defined as the percentage of new GA emerging from the intermediate dry AMD group during the follow-up. Baseline phenotypes were evaluated in the prevalent GA group at the initial visit using fundus photography, spectral-domain optical coherence tomography, and fundus autofluorescence (FAF). Progression patterns were assessed by growth rates (mm/year and mm/year using square-root treansformation [SQRT]), and the centripetal growth direction (foveal involvement of extrafoveal lesions). Linear regression was used to identify factors associated with progression rates.

RESULTS

In intermediate dry AMD group (395 eyes/241 patients), GA incidence was 6.8%, while wet conversion was 14.4%, during 60.5 ± 13.5 months. In prevalent GA group (70 eyes/46 patients), the mean lesion size was 7.2 ± 7.1 mm (2.4 ± 1.3 mm [SQRT]), with bilateral involvement in 68.6%, banded/diffuse FAF patterns in 81.4%, extrafoveal and multifocal locations in 51.4% and 84.3%, and drusen and reticular pseudodrusen in 87.1% and 34.3%. The progression rate was 2.0 ± 1.3 mm/year (0.3 ± 0.2 mm/year [SQRT]), with 69.4% exhibiting centripetal direction during 61.2 ± 14.5 months. Large lesion size, banded/diffuse FAF patterns, and extrafoveal locations were positively associated with progression rates (p = 0.006, 0.007, and 0.008).

CONCLUSIONS

The 5-year incidence of GA in Korean patients with intermediate dry AMD was 6.8%, approximately half of the rate of wet conversion. The mean GA progression rate was 2.0 mm/year (0.3 mm/year [SQRT]). Risk factors for fast progression were banded/diffuse FAF patterns, extrafoveal locations, and large lesion size.