Ginkgo biloba extract increases ocular blood flow velocity

We evaluated a possible therapeutic effect of Ginkgo biloba extract (GEE) on glaucoma patients that may benefit from improvements in ocular blood flow. A Phase I cross-over trial of GEE with placebo control in 11 healthy volunteers (8 women, 3 men: Age; 34 +/- 3 years, mean +/- SE) was performed. Patients were treated with either GEE 40 mg or placebo three times daily orally, for 2 days. Color Doppler imaging (Siemens Quantum 2000) was used to measure ocular blood flow before and after treatment. There was a two week washout period between GEE and placebo treatment. Ginkgo biloba extract significantly increased end diastolic velocity (EDV) in the ophthalmic artery (OA) (baseline vs GEE-treatment; 6.5 +/- 0.5 vs 7.7 +/- 0.5 cm/sec, 23% change, p=0.023), with no change seen in placebo (baseline vs GEE-treatment; 7.2 +/- 0.6 vs 7.1 +/- 0.5 cm/sec, 3 % change, p=0.892). No side effects related to GEE were found. Ginkgo biloba extract did not alter arterial blood pressure, heart rate, or IOP. Ginkgo biloba extract significantly increased EDV in the OA and deserves further investigation in ocular blood flow and neuroprotection for possible application to the treatment of glaucomatous optic neuropathy as well as other ischemic ocular diseases.