Understanding Geographic Atrophy
Geographic atrophy (GA) or dry age-related macular degeneration (AMD) is an advanced form of age-related macular degeneration (AMD) that leads to progressive and irreversible vision loss.1 Early or intermediate AMD may progress to the advanced forms, which include neovascular AMD (“wet” AMD) or GA (“dry” AMD),2 and the risk of developing AMD increases with age.
AMD is the leading cause of permanent vision loss in people over the age of 65 in developed countries.3 Based on published studies, approximately five million people have GA globally.4,5
While there are multiple effective treatments available for wet AMD, there are currently no approved treatments for GA.
In people with GA, photoreceptors, which are light sensitive cells, deteriorate in the macula, a central portion of the retina responsible for central vision and color perception.6 This damage starts as small spots that grow into larger patches. As the cells in the macula die, the person starts to lose vision.6
A person with early AMD may notice problems with reading or night vision.7 Eventually, if the disease progresses to advanced stages, permanent blind spots (scotomas) in the center of the visual field will develop.
The cause of GA is thought to be multifactorial, with numerous environmental and genetic risk factors. The dysregulation of the complement cascade, an important part of the body’s immune system, plays a pivotal role.7
Excessive activation of the complement cascade results in destruction of healthy cells, which can lead to the onset or progression of many diseases including GA.8,9