Longitudinal Changes of Visual Sensitivity With Geographic Atrophy Progression Assessed by Defect-Mapping...

Area of Science:

• Ophthalmology
• Retinal Diseases
• Visual Neuroscience

Background:

• Geographic atrophy (GA) is a leading cause of irreversible vision loss.
• Understanding the relationship between structural and functional changes in GA progression is crucial for developing effective treatments.
• Current methods for assessing GA progression may not fully capture the dynamic interplay between structural changes and visual function decline.

Purpose of the Study:

• To determine the relationship between structural and functional changes over time in the progression of geographic atrophy (GA).
• To assess GA progression using defect-mapping microperimetry, a method optimized for characterizing spatial extent of visual sensitivity losses.
• To evaluate the utility of defect-mapping microperimetry in capturing visual function decline associated with GA progression.

Main Methods:

• Fifty eyes from 50 participants underwent defect-mapping microperimetry testing within the central 8° radius.
• Testing involved 208 locations with 10-dB stimuli, repeated over a median of five visits at 3-month intervals.
• Geographic atrophy (GA) lesion extent on fundus autofluorescence was manually annotated at each visit and correlated with microperimetry results.

Main Results:

• Global change in GA extent explained a significant portion of the variance in missed microperimetry locations (R² = 0.52).
• Local analysis revealed that test locations with increasing GA overlap showed a higher probability of functional worsening (up to 37.9% with 75-100% overlap).
• Test locations within GA lesions had a 2.3% probability of worsening, while those outside had a 0.3% probability.

Conclusions:

• Longitudinal changes in GA extent are significantly associated with functional changes measured by defect-mapping microperimetry.
• These findings confirm the functional relevance of GA progression and the effectiveness of this microperimetry strategy.
• Defect-mapping microperimetry is a promising tool for monitoring visual function decline in geographic atrophy.