Retinal sensitivity and choriocapillaris flow are potential early markers of GA progression

This cross-sectional, single-center study analyzed swept-source OCTA images of choriocapillaris perfusion along with measurements of retinal sensitivity to examine the relationship of these two factors as potential early markers of geographic atrophy (GA) progression.

Study design

This single-center, cross-sectional study included 18 eyes of patients with GA secondary to nonexudative AMD and no history or evidence of choroidal neovascularization, and 7 eyes of healthy patients. Swept-source OCTA en face choriocapillaris perfusion images were obtained. The percent area of nondetectable choriocapillaris flow / flow deficits was calculated in the en face OCTA images total analyzed area and for each region of interest. Retinal sensitivity was measured by fundus-guided microperimetry.

Outcomes

When compared with healthy people, patients with GA had greater choriocapillaris flow deficits (mean ± SD: 24.2% ± 7.9% vs 7.9% ± 2.3%) and lower retinal sensitivity (mean difference ± SD: –17.0 ± 1.2 dB). In patients with GA, the choriocapillaris flow deficit decreased (r = –0.40) and retinal sensitivity increased (r = +0.63) in areas farther from the GA margin. Choriocapillaris flow deficits inversely correlated with retinal sensitivity (r = –0.61).

Limitations

The study has a relatively small sample size. The temporal relationship between the loss of choriocapillaris flow, GA, and retinal sensitivity was not studied in this cross-sectional analysis.

Clinical significance

This study shows that reduced retinal sensitivity correlates with increased choriocapillaris flow deficit. As therapies for GA are studied and become more available, detecting earlier markers of disease progression will become increasingly important. However, longitudinal studies of choriocapillaris flow, GA, and retinal sensitivity are needed to establish choriocapillaris flow deficits as an early marker of GA progression.