Geographic Atrophy

A sharply circumscribed area of geographic atrophy of the RPE (>125 microns) associated with atrophy of the choriocapillaris and photoreceptors; choroidal vessels can be seen within the atrophied area.
  • Represents the most advanced form of nonneovascular AMD.
  • Pathogenesis is unclear, but may raise from:
    • Areas of confluent large, soft drusen that undergone regression
    • Multiple reticulated areas of hyper- or hypopigmentation (non-geographic atrophy) which may progress to one large area of GA, spreads contiguously around the fovea and eventually surrounding it
    • Spontaneous flattening of a pigment epithelial detachment

Clinical Features

  • Symptoms:
    • Gradual or progressive loss of vision, depending on the extend and the location of the atrophy relative to the foveal center
    • Reduced contrast sensitivity
  • Signs:
    • Single or multiple discrete areas of hypopigmentation or depigmentation or absent of the RPE forming an areolar pattern 
    • Often appear as bilateral and symmetric disease, although they may have different onset and progression rates 
    • Visualization of the larger caliber choroidal vessels within the atrophied area
    • May be accompanied by calcified drusen which appears as glistening, bright yellow specks 
    • The areas of atrophy will continue to enlarge over time

Fluorescein angiography findings:

  • Early and discrete bright hyperfluorescence
  • Slowly or entirely absent of choriocapillaris filling within the GA zone
  • Persistent staining of the atrophied area with a maintaining border in the late phase