To develop a multiscale analysis framework for investigating the relationships between geographic atrophy (GA) growth rate and choriocapillaris (CC) blood flow impairment using optical coherence tomography (OCT) and OCT angiography (OCTA).

Retrospective case series.

We developed an OCT/OCTA analysis framework that quantitatively measures GA growth rates at global and local scales and CC impairment at global, zonal, and local scales. A geometric GA growth model was used to measure local GA growth rates. The utility of the framework was demonstrated on 7 eyes with GA imaged at 2 time points using a prototype 400-kHz, 1050-nm swept-source OCTA system.

Qualitatively, there was a trend of increasing GA growth rate with increasing CC impairment. The local analysis model enabled growth rates to be estimated at each point on the GA boundary. However, there was no generally observed trend between local GA growth rates and local CC impairment.

The global, zonal, and local analysis framework may be useful for investigating relationships between GA growth and CC impairment at different spatial scales. The geometric GA growth model enables spatially resolved growth measurements that capture the anisotropy of GA growth and may improve the characterization of GA progression.