Objective: To evaluate the effect of Ginkgo biloba extract (GBE) on preexisting visual field damage in patients with normal tension glaucoma (NTG).
Design: Prospective, randomized, placebo-controlled, double-masked cross-over trial.
Participants: Twenty-seven patients with bilateral visual field damage resulting from NTG.
Intervention: Patients received 40 mg GBE, administered orally, three times daily for 4 weeks, followed by a wash-out period of 8 weeks, then 4 weeks of placebo treatment (identical capsules filled with 40 mg fructose). Other patients underwent the same regimen, but took the placebo first and the GBE last. Visual field tests, performed at baseline and at the end of each phase of the study, were evaluated for changes.
Main outcome measures: Change in visual field and any ocular or systemic complications.
Results: After GBE treatment, a significant improvement in visual fields indices was recorded: mean deviation (MD) at baseline versus MD after GBE treatment, 11.40 +/- 3.27 dB versus 8.78 +/- 2.56 dB (t = 8.86, P = 0.0001, chi-square test); corrected pattern standard deviation (CPSD) at baseline versus CPSD after GBE treatment, 10.93 +/- 2.12 dB versus 8.13 +/- 2.12 dB (t = 9.89, P = 0.0001, chi-square test). No significant changes were found in intraocular pressure, blood pressure, or heart rate after placebo or GBE treatment. Any ocular and systemic side effects were recorded for the duration of the trial.
Conclusions: Ginkgo biloba extract administration appears to improve preexisting visual field damage in some patients with NTG.