Geographic Atrophy Size Progression Correlates Better with Longitudinal Changes in Quantitative Contrast Sensitivity...

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• Geographic atrophy (GA) is an advanced stage of age-related macular degeneration (AMD) characterized by progressive vision loss.
• Current methods for assessing GA progression and treatment efficacy often rely on visual acuity (VA), which may not fully capture functional decline.

Purpose of the Study:

• To investigate the cross-sectional and longitudinal correlations between total geographic atrophy (GA) size and quantitative contrast sensitivity function (qCSF).

Main Methods:

• A prospective, observational study involving 83 eyes with GA cross-sectionally and 30 eyes longitudinally.
• Measurements included contrast sensitivity (CS) using qCSF, spectral-domain OCT, and fundus autofluorescence (FAF) to assess GA size.
• Mixed-effects multivariate regression models were used to analyze associations between GA size, qCSF metrics, and VA.

Main Results:

• Cross-sectionally, GA size was significantly associated with multiple qCSF outcomes, including area under the logarithm of contrast sensitivity function (AULCSF) and CS thresholds at various spatial frequencies (P < 0.05).
• Longitudinally, an increase in GA size was associated with statistically significant decreases in CS metrics (AULCSF, low contrast VA [LCVA], CS thresholds) but not with VA (P > 0.05).
• The impact of GA size increase on CS metrics was substantially greater (11-20 fold) than its non-significant impact on VA.

Conclusions:

• Total GA size and its longitudinal changes are significantly associated with changes in qCSF, highlighting CS as a sensitive functional endpoint.
• Contrast sensitivity, measured by qCSF, appears to be a more effective functional endpoint than VA for evaluating treatment effects in GA.
• These findings support the use of qCSF in clinical trials for GA to better detect treatment-induced functional improvements.