Longitudinal Analysis Of The Topographic Progression Of Geographic Atrophy Secondary To Age-related Macular Degeneration

Abstract

 

Purpose:

 

To determine the topographic progression of geographic atrophy (GA) in patients with age-related macular degeneration (AMD).

 

Methods:

 

Confocal scanning laser ophthalmoscopy fundus autofluorescence images (FAF, exc = 488, em 500-700nm) from 410 eyes of 410 patients (median age 77.0 years, Inter quartile range [IQR] 72.0 - 82.8 years) of the Geographic Atrophy Progression (GAP)- study were retrospectively analyzed. Using a modified Early Treatment Diabetic Retinopathy Study (ETDRS) grid to divide the posterior pole into nine different subfields plus periphery, the localization, size and progression of atrophic patches were determined over time. GA progression rates in different subfields, zones (center, inner and outer) and slices (nasal, temporal, inferior, superior) were compared using the Friedman-test.

 

Results:

 

The center and inner zones were involved in almost all patients (>95%), while atrophy was less common in the subfields of the outer zone (76%). Retinal areas beyond the ETDRS grid were affected in only 10%. Inner zone atrophy size (median 3.99mm²) and progression rate (0.67mm²/year) were significantly greater than in the outer zone (0.59mm² and 0.42mm²/year) (p <0.001), respectively. There was a trend towards outer zone subfield and periphery involvement with increasing total size of atrophy.

 

Conclusions:

 

Distribution and progression of existing GA patches depend both on the eccentricity from the center and total GA size. Central macula areas appear most susceptible for the occurrence and expansion of GA. Refined analysis of distribution and directional spread is important to understand the natural history of the disease and for the definition of efficacy endpoints in interventional clinical trials.

 

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