Effect of Ginkgo Biloba Extract on Macula and Peripapillary Perfusion Examined Using Optical Coherence Tomography Angiography

Objective: To evaluate the effect of ginkgo biloba extract (GBE) on optical coherence tomography angiography (OCT-A) macula and peripapillary perfusion parameters among patients with treated early-to-moderate primary open-angle glaucoma.

Design: Clinical trial.

Participants: Seventeen patients with early-to-moderate (≥10 dB MD) primary open-angle glaucoma were matched to 17 control patients based on age, sex, and glaucoma status. A total sample size of 34 was determined for effect size 0.5, alpha 0.05, power 0.81, and critical t = 2.03. Normality was confirmed using the Kolmogorov-Smirnov and Shapiro-Wilk tests.

Methods: The intervention was 120 mg oral GBE twice daily for 4 months. OCT-A scans (15° × 15°) of the macula and peripapillary retina were acquired, two-dimensional projection slab images of the superficial vascular complex were exported, and image analysis was performed. Student's t test was used to compare perfusion density between groups, and between baseline and follow-up for each group. The main outcomes were perfusion density of the superficial vascular complex of the macula and the peripapillary region.

Results: Comparison between baseline and 4 months' supplementation with GBE revealed no significant change in perfusion density in the macular area, 0.32 (0.04) versus 0.30 (0.04); p = 0.17, and was significantly lower in the peripapillary area, 0.44 (0.05) versus 0.42 (0.04); p = 0.02. No differences were observed in the control group.

Conclusion: Four-month supplementation with GBE did not result in clinically significant improvement in macula or peripapillary perfusion density in patients with treated early-to-moderate primary open-angle glaucoma. Larger studies are needed to confirm an absence of neuroprotective effects of GBE.