Geographic atrophy

Geographic Atrophy

Fundus image showing geographic atrophy

Geographic atrophy (GA) is an advanced form of age-related macular degeneration (AMD), a progressive eye condition that affects the retina. It is characterized by the degeneration of the retinal pigment epithelium (RPE) and the overlying photoreceptors, leading to a gradual loss of central vision.

Pathophysiology

Geographic atrophy occurs when there is a progressive loss of the RPE, which is crucial for the maintenance and function of the photoreceptor cells. The RPE provides essential support to the photoreceptors, including the recycling of visual pigments and the phagocytosis of photoreceptor outer segments. In GA, the degeneration of the RPE leads to the death of the overlying photoreceptors, resulting in areas of atrophy that appear as well-demarcated regions on the fundus of the eye.

Clinical Features

Patients with geographic atrophy typically experience a gradual decline in central vision. The condition is often bilateral, affecting both eyes, although the severity may differ between eyes. Symptoms include difficulty reading, recognizing faces, and performing tasks that require fine visual acuity. The progression of GA can vary, with some patients experiencing a slow decline over many years, while others may have a more rapid progression.

Diagnosis

The diagnosis of geographic atrophy is primarily made through a comprehensive eye examination and imaging studies. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) are commonly used to assess the extent of atrophy and monitor its progression. On fundus examination, GA appears as well-defined areas of depigmentation, often with visible underlying choroidal vessels.

Management

Currently, there is no cure for geographic atrophy. Management focuses on monitoring the progression of the disease and providing supportive care to optimize remaining vision. Patients may benefit from low vision aids and visual rehabilitation services. Research is ongoing to develop treatments that can slow the progression of GA, including gene therapy, stem cell therapy, and pharmacological interventions targeting the underlying pathophysiological mechanisms.

Related Pages

• Age-related macular degeneration
• Retinal pigment epithelium
• Photoreceptor cells
• Optical coherence tomography