Impact of Ginkgo Biloba Extract on VF Progression in NTG
In this retrospective study, investigators evaluated the long-term effect of Ginkgo biloba extract (GBE) on progression of visual field (VF) defects in patients with normal tension glaucoma (NTG).
They evaluated 42 eyes of 42 patients with treated NTG who received 80 mg GBE 2 times daily and who had at least 5 VF tests using the Humphrey Visual Field Analyzer for more than a 4-year period before and after GBE treatment.
They also evaluated the change of progression rate using mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI) after GBE treatment. Additionally, the investigators analyzed time course of mean total deviation in 10 zones corresponding to the glaucoma hemifield test using a linear mixed effects model with unequal random effect variances.
They noted that the mean follow-up period was 12.3 years and found that the post-therapeutic IOPs before and after GBE treatment were not significantly different (p=0.509 paired t test). The study investigators also reported that before GBE treatment, the regression coefficients (RCs) of MD, PSD and VFI change were –0.619 dB/y, 0.626 dB/y, and –2.153%/y, respectively. After GBE treatment, the RCs of MD, PSD, and VFI change improved significantly to –0.379 dB/y, 0.342 dB/y, and –1.212%/y (p <0.001), respectively. In zone 1, the RC of mean total deviation change was significantly increased after GBE administration (p <0.005).
In conclusion, GBE administration slowed the progression of VF damage in patients with NTG, especially in zone 1 corresponding to the superior central field.