Why gingko may not help some glaucoma patients as well as others

Gingko, known for nerve and vascular protection qualities, may not help glaucoma patients as much as thought. At least in some patients.A small prospective pilot study was conducted to investigate the supplement’s effect on the microvasculature in the retina using optical coherence tomography angiography (OCT-A). Findings were published in the Canadian Journal of Ophthalmology (CJO). Unlike Doppler ultrasound, which can be used to examine large vessels in the eye, OCT-A provides detailed information about retinal microvasculature. Studies suggest vascular dysregulation may contribute to glaucoma progression in some patients, and that gingko bilboa (GBE) may be useful. “Studies examining systemic vascular ischemic diseases have shown a beneficial effect of GBE on systemic arterial occlusive diseases. A recent study reported that in patients with glaucoma, antioxidants, including GBE, improved ocular blood flow measured using Doppler ultrasound of the ophthalmic artery,” the study said.But the effect of the compound on microvasculature is not established. To study this, the researchers recruited 17 patients with early to moderate primary open-angle glaucoma to receive either GBE supplementation or placebo, and undergo before and after OCT-A imaging.Exclusion criteria included patients with a history of ocular disease that affected ocular perfusion, prior incisional glaucoma surgery, patients on anticoagulant therapy or who had blood disorders, and those using drugs that could potentially interact with GBE such as nonsteroidal anti-inflammatory agents, risperidone, amiodarone or several other medications.Patients in the GBE group were directed to take 120mg of GBE in the form of soft gels twice daily for four months.At four months follow-up time, there was no statistically significant difference between baseline and follow-up perfusion density in the macula area, while there was a reduction in the peripapillary area perfusion density in the GBE group. The control group had no statistically significant difference in the perfusion density changes in either area.“Our pilot study suggests that 4-month supplementation with ginkgo biloba extract does not result in a clinically or statistically significant increase in perfusion density of the macula and peripapillary area in patients with treated early-to-moderate primary open-angle glaucoma,” the study said.However, the authors noted that various previous studies showed positive results with GBE in glaucoma patients. They described one study which showed that retinal ganglion cells had significantly better survival with treatment with GBE compared to a control eye in a rat model. Another study which looked at 42 patients with normal tension glaucoma who received GBE supplements for at least four years had a reduction in the progression of visual field damage. And yet another study, one with 103 normal tension glaucoma patients who received GBE supplementation for an average of 23 months, had improvements in visual field tests. The difference could be related to patient characteristics. “The patients in our study were older and had primary open-angle glaucoma with previously elevated IOP, compared to the healthy young subjects or normal tension glaucoma patients that comprised the prior studies. Some of the risk factors for normal tension glaucoma include low blood pressure, nocturnal hypotension, migraine, and Raynaud’s phenomenon. As such, the potential positive vascular effects of GBE may be more beneficial for patients with lower IOP,” they wrote.

Why gingko may not help some glaucoma patients as well as others

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