Progression of Primary Geographic Atrophy in Patients with Age-Related Macular Degeneration and Relation to Reticular Macular Disease

Abstract

 

Purpose:

 

To determine progression of primary geographic atrophy (GA) in age-related macular degeneration (AMD) and factors related to its progression using fundus autofluorescence (FAF) and near infrared (IR) images.

 

Methods:

 

121 eyes of 90 patients with a diagnosis of primary GA were retrospectively identified. A minimum of 2 examinations with FAF or IR imaging were performed at least 6 months apart. Exclusion criteria were other macular diseases or atrophy secondary to choroidal neovascularization. Areas of GA and progression rates were calculated using custom interactive software. At baseline, the presence of reticular macular disease (RMD), also known as reticular pseudodrusen or subretinal drusenoid deposits, and of peripapillary atrophy were determined. GA was classified into unilobular or multilobular patterns and foveal or extrafoveal in location. Areas of GA and of RMD were determined in each of the 5 fields of a modified Wisconsin grid.

 

Results:

 

The mean duration of follow-up was 19.4 months (range 6 - 51 months). The mean age at baseline was 83 years (standard deviation ±6.8 years). At baseline, 103 (85.1%) eyes showed peripapillary atrophy and 115 (95%) had RMD. The GA pattern was unilobular in 6 eyes (4.9%) and multilobular in 115 (95%) and the GA location was extrafoveal in 31 eyes (25.6%). Four eyes progressed to foveal GA. Three of these had the multilobular pattern. The mean GA size at baseline was 2.8mm². The mean GA growth rate was 0.8mm²/yr with a statistically significantly difference between the unilobular (0.2mm²/year) and multilobular groups (0.8mm²/year, p=0.003). With respect to initial GA size, the lower 50th percentile had a lower progression rate than the upper 50th percentile (0.6mm²/year vs 1.0 mm²/year, p<0.05). Among eyes that presented with RMD, 113 (98.3%) showed GA progressing in areas previously involved by RMD. Age and gender did not influence GA progression (p<0.05).

 

Conclusions:

 

Serial imaging suggests that the progression rate of primary GA is higher in eyes with larger initial lesions size and a multilobular pattern. The high correlation between the presence of RMD and primary GA may imply a common pathway. The observation of GA expanding in areas of RMD suggests that reticular macular disease could correspond to the beginning of retinal atrophy.

 

Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: natural history • imaging/image analysis: clinical