A recent study tries to paint a clearer picture of the correlation between structural and functional markers of geographic atrophy.

Sandrine H. Künzel, MD
University Eye Hospital Bonn
Germany

The variability of geographic atrophy (GA) progression in patients makes monitoring the disease challenging. Although atrophy tends to spread more rapidly in the direction of the periphery of the retina, there is no predictive marker that indicates the direction of spread from the center. Furthermore, the impact of GA on the patient cannot be effectively correlated with common markers of visual function, including best-corrected visual acuity and lesion size.

Vision-Related QOL

Vision-related QOL (VRQOL) captures the patient’s disease experience and GA’s impact on daily life activities, which makes it an important tool to measure patient outcomes. However, few studies have explored the correlation between structural and functional markers of GA, and the existing studies offer conflicting results.

Sandrine H. Künzel, MD, and colleagues conducted a prospective, non-interventional, natural history “Directional Spread in Geographic-Atrophy” study to clarify the correlation between lesion placement and VRQOL in patients with GA. “Our study investigates the relevance of a variety of GA determinants to VRQoL to aid clinicians in making this determination,” Dr. Künzel and colleagues wrote in medRχiv. “To our knowledge, this paper is the first to analyze the relative contribution of structural and functional markers of GA to VRQOL in individuals with AMD.”

The study included 82 participants diagnosed with GA. Among them, 42 were female and 39 were male; the mean age ± standard deviation (SD) was 77.2 ± 7.5 years at baseline. The average detected area of GA was 2.9 ± 1.2 mm² for the better eye (BE) and 3.1 ± 1.3 mm² for the worse eye.

The median score collected from participants who completed the National Eye Institute Visual Function Questionnaire 25 was 70. This questionnaire includes 25 questions that contribute to a composite score and 12 subsets that touch upon a variety of vision-related functioning in daily life. Scores range between 0 to 100 with 100 indicating the highest vision-related functionality.

To understand the Early Treatment Diabetic Retinopathy Study (ETDRS) subfields applied to assess reading acuity, the team performed univariate and multivariate regressions. The researchers noted that the subfields of the BE tended to correlate with a higher VRQOL score. Specifically, the most relevant subfields were the inner lower and inner left areas of the BE (Figure).

Sight in Darkness

Low-luminance visual acuity (LLVA) of BE was the most stand-out factor noted on the composite scale, followed by the inner lower subfield, inner left subfield, and reading speed—all pertaining to BE. LLVA of BE continued its prominence for the multivariate regression across all three scores.

Of all participants, 43 were diagnosed with foveal-sparing GA and analyzed separately. In these examinations, the univariate regression showed the influence of the inner lower subfield of the BE to the compiled composite and distance activity scores when limited to ETDRS subfields.

“This study demonstrates the relative value of structural and functional GA markers to VRQOL,” concluded Dr. Künzel and colleagues. “The inner left and inner lower subfields were most relevant for near activities and distance activities, respectively. Of the functional markers, LLVA was a notable contributor within the analysis. These findings can inform treatment decisions in regard to recently approved interventions for GA secondary to AMD.”