Progressing geographic atrophy: choroidal thickness and retinal sensitivity identify two clinical phenotypes

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• Geographic atrophy (GA) is a progressive form of age-related macular degeneration.
• Understanding GA progression and associated factors is crucial for developing effective treatments.
• The role of choroidal neovascularisation (CNV) in the fellow eye on GA progression is not fully understood.

Purpose of the Study:

• To analyze changes in choroidal thickness and retinal sensitivity (Se) in patients with geographic atrophy (GA).
• To compare these changes in patients with GA with and without choroidal neovascularisation (CNV) in the fellow eye.

Main Methods:

• Study included patients with bilateral GA (B-GA) and unilateral GA with CNV in the fellow eye (U-GA).
• Follow-up was conducted every 6 months, evaluating enhanced depth imaging optical coherence tomography (OCT), fundus autofluorescence (FAF), and microperimetry.
• Measurements included GA area, choroidal thickness, and retinal sensitivity (Se) at baseline and during follow-up.

Main Results:

• Mean GA area increased significantly in both groups during follow-up.
• Choroidal thickness was significantly greater in the B-GA group compared to the U-GA group at baseline and follow-up.
• Choroidal thickness decreased significantly only in the U-GA group, while retinal sensitivity (Se) decreased significantly only in the B-GA group.

Conclusions:

• Changes in retinal sensitivity and choroidal thickness differ between patients with GA with or without CNV in the fellow eye.
• These findings suggest at least two distinct GA phenotypes.
• The development and progression of GA may be driven by different pathophysiologic mechanisms in these phenotypes.