Functional Effects of Epigallocatechingallate on Retinal Function in Glaucoma

Twenty ocular hypertension and twenty early open angle glaucoma patients will be randomly divided into two groups: 1. placebo group [ocular hypertension, n = 10, early glaucoma (n=10)], taking an oral placebo in addition to standard beta-blocker treatment for ocular hypertension; 2. Treatment group [ocular hypertension, n = 10, early glaucoma (n=10)], taking Epigallocatechingallate oral treatment (200 mg/day) in addition to standard beta-blocker treatment for ocular hypertension. The patients will undergo standard clinical examination including automated Humphrey perimetry (30-2), pattern electroretinogram recording and measurement of retinal nerve fiber layer thickness by Optical Coherence Tomography (OCT stratus) at baseline, 3 and 6 months of treatment and follow-up. All patients will be again tested at 3 and 6 months after changing, in a cross-over design, placebo with drug assumption and vice versa.

Main outcome measure will be pattern electroretinogram amplitude. Secondary measures will be Humphrey perimetry mean deviation and corrected pattern standard deviation, and the thickness of optic nerve fibers measured by OCT.

Pattern Electroretinogram recordings.

Stimuli will be horizontal gratings of 1.6 cycles/degree spatial frequency, modulated in counterphase at 8.14 Hz and electronically generated on a high-resolution TV monitor (contrast: 70%; mean luminance: 80 cd/m2; field size: 31° [width] x 24° [height]). Subjects fixate at the center of the stimulating field with natural pupils, whose size will be measured, at a viewing distance of 57 cm. The subjects or patients will wear full refractive correction for the test distance. Signals will be recorded by a standard, flat-cup, 9 mm Ag/AgCl electrode taped on the skin of the lower eyelid. A similar electrode, placed over the eyelid of the contralateral, unstimulated eye, will be used as reference. Responses will be amplified (100, 000), bandpass filtered (1-30 Hz), sampled with a resolution of 12 bits and averaged (250 events) with automatic artifact rejection. Two replications will be obtained for each record to verify reproducibility. Peak-to-peak amplitude (in microV) of the Fourier analyzed response 2nd harmonic will be measured.

Retinal Nerve Fiber Thickness by OCT