Gingko BilobaMeasurement of the Effect of Gingko Biloba Extract on Ocular and Nailfold Blood-flow in NTG

Inclusion Criteria:

Male or female of any race, at least 18 years of age

• Has provided verbal and written informed consent.
• Able and willing to follow instructions, including participation in all study assessments and visits.
• Eyes with NTG will be enrolled.
• Glaucoma severity will be graded using the WHO (World Health Organization)staging system.

NTG diagnosis will be based on the following:

1. Glaucomatous optic disc on slit-lamp biomicroscopy defined as cup-to-disc ratio greater than 0.7, inter-eye asymmetry in cup-to-disc ration greater than 0.2 or neuroretinal rim notching, focal thinning, disc hemorrhage or vertical elongation of optic disc.
2. Glaucomatous visual field defects on at least three reliable visual field examinations as measured by a glaucoma hemifield test (GHT) result outside normal limits and/or the appearance of at least three consecutive test points on the pattern deviation plot with p<1% and at least one at p<0.05%, not including points on the edge of the field.
3. NTG will be defined as those subjects with a history of untreated peak IOP ≤21 mmHg.

• Both eyes will be enrolled

Exclusion Criteria:

• Best-corrected visual acuity less than 20/40
• Age younger than 18 years or older than 85 years
• Refractive error greater than +3.00 diopters (D) or less than -7.00 diopters (D)
• Previous intraocular surgery except for uncomplicated cataract extraction with posterior chamber intraocular lens implantation
• Any other diseases that may cause visual field loss or optic disc abnormalities
• Inability to perform reliably on automated visual field testing.
• Subjects taking any GBE product will be washed out for 2 weeks prior to enrollment.
• Diabetes.
• Seizure disorder.
• Taking any drugs that may interact with GBE (as listed).