Variation in Mesopic Retinal Sensitivity Relative to Distance from Geographic Atrophy in Age-Related Macular...

Area of Science:

• Ophthalmology
• Retinal imaging
• Age-related macular degeneration (AMD) research

Background:

• Age-related macular degeneration (AMD) is a leading cause of vision loss.
• Geographic atrophy (GA) is an advanced form of AMD characterized by progressive photoreceptor and retinal pigment epithelium cell death.
• Understanding the relationship between GA lesion borders and visual function is crucial for managing AMD progression.

Purpose of the Study:

• To analyze the relationship between the distance from geographic atrophy (GA) lesion borders and mesopic retinal sensitivity in patients with age-related macular degeneration (AMD).

Main Methods:

• Utilized longitudinal microperimetry data from a phase II clinical trial.
• Assessed mesopic retinal sensitivity using a fundus-guided microperimetry device with a custom T-shaped test pattern.
• Calculated the distance from the closest GA lesion border (GA distance) for individual test loci.
• Employed repeated-measures regression to analyze the relationship between GA distance and retinal sensitivity.

Main Results:

• A significant perilesional zone of approximately 2.05° (∼580 μm) around GA borders was identified where retinal sensitivity changes steeply.
• Retinal sensitivity increased quadratically for GA distances <2.05° (approx. 1.99 dB/°) and linearly for distances ≥2.05° (approx. 0.56 dB/°).
• A significant decline in retinal sensitivity over time was also observed (-0.07 dB/month).

Conclusions:

• A distinct perilesional zone around GA borders exhibits rapid changes in retinal sensitivity.
• This zone is a key area for evaluating interventions aimed at preserving or restoring visual function in AMD.
• Decreased visual function extends beyond GA borders, impacting clinical trial design and understanding of AMD pathophysiology.