Predictors of Geographic Atrophy Growth and Visual Decline in a longitudinal Asian cohort.

Purpose

To characterize GA growth and visual outcomes in Asian eyes with geographic atrophy (GA) secondary to age-related macular degeneration and to evaluate the incremental prognostic value of deep learning-derived optical coherence tomography (OCT) biomarkers.

Design

Prospective longitudinal observational cohort study.

Participants

One hundred fifty-five eyes of 139 patients with GA and 12-month follow-up.

Methods

Participants underwent baseline and month-12 multimodal imaging with fundus autofluorescence (FAF) and spectral-domain OCT. GA area was quantified on FAF. A validated deep learning algorithm segmented retinal pigment epithelium layer loss (RPEL), photoreceptor degeneration (PRD), hypertransmission (HTR), and retinal pigment epithelium and outer retinal atrophy (RORA). Layer-specific excess metrics beyond RORA were derived. Multivariable mixed-effects models were constructed to identify predictors of GA growth and month-12 best-corrected visual acuity (VA), with nested models assessing incremental value beyond conventional demographic and imaging features. MAIN OUTCOME MEASURES Twelve-month change in GA area and month-12 VA.

Results

Mean baseline GA area was 3.89±4.24 mm2 and increased by 0.83±0.92 mm2 at month 12 (P<0.01). In lesions with baseline area ≥2.5mm2, one year growth rate was 1.32 ± 0.96 mm2. Baseline GA area, multifocality, and subretinal drusenoid deposits (SDD) were independently associated with faster growth. When analysed by baseline GA area, SDD were associated with increased growth in eyes with smaller baseline GA area (<2.5mm2). PRD-RORA excess was independently associated with GA growth and provided incremental predictive value beyond conventional predictors (ΔR2=0.02, P=0.04). Predictors differed by baseline lesion size. Mean VA decreased minimally from 0.68±0.56 at baseline to 0.72±0.57 logMAR at 1-year (P<0.01). Central 1-mm OCT occupancy measures provided greater explanatory value for month-12 VA than 6-mm OCT occupancy.

Conclusions

Photoreceptor degeneration extending beyond established atrophy provided modest incremental prognostic information beyond conventional features evaluated. Central 1-mm OCT features showed limited association with month-12 VA and may serve as complementary structural correlates of visual function.