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

GBE has been reported to improve blood flow to the brain, eye, and extremeties(hands,
feet,etc.). .As with most supplements, GBE is neither regulated nor FDA approved.

A technique called Optical Coherence Tomography Angiography (OCTA),will be used to measure
the small blood vessels at the back of the eye, the macula (the area of sharpest vision), and
the optic disc (the point at which the nerve fibers from the retina enter to form the optic
nerve, which transmits visual impulses to the brain). This technique uses a camera, capable
of imaging the smallest vessels, so that their density (number) can be calculated by a
computer. This is being done to determine if there is disease causing increasing loss of
these vessels. The imaging is done by a widely used camera which does not contact the eye. It
simply uses visible light to measure the amount of blood vessels present in a determined area
in the back of the eye. Blood flow at the 4th finger nailfold (nailfold capillaroscopy; NFC)
is a standard technique, especially in rheumatology, performed by using a commercially
available light microscope which glides over the base of the fingernail and can image the
tiny capillaries in the nailfold. These images are recorded as videos from which the blood
flow can be analyzed by freely available software for the purpose of quantitative
measurements (amount of blood flow and blood flow velocity).

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 80 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).