Effect of Metformin on Visual Function in Patients With Glaucoma

• Age between 18-65 years old;
• The baseline value of intraocular pressure ≤ 21 mmHg in either eye whether untreated or treated by ≤ 2 eye drops (laser or filtering surgery should be performed over 3 months).
• Over two times of experience of visual field examination (24-2 or 30-2 visual field examinations) in the past two years, or false positive/false negative ratio less than 33%;
• Diagnosed POAG by Glaucoma specialists from Zhongshan Ophthalmic Center with open angle, and impairment in optic disc or visual field in one or both eyes.
• Patient is at risk of glaucomatous progression, as determined by the documented presence of optic disc hemorrhage within 12 months in either eye, OR ≥2 of the following risk factors:
• Vertical cup-to-disc ratio >0.8 in one or both eyes
• Mean deviation in visual field worse than \<10 dB in either eye (verified by the reading center)
• Pseudoexfoliation in either eye
• Family history (parent or sibling) of glaucoma
• Hypertension
• Systemic hypertension requiring medical treatment Migraine (defined by the International Headache Society with or without aura, Raynaud's syndrome, or both:

• The main organs are functioning normally and meet the following criteria:

  1. Blood sample should meet the following criteria: (no blood transfusion within 14 days) A. Hemoglobin (> 90g/L); B. Platelet count (>105*10e9/L)
  2. Biochemical and urinary examinations should meet the following criteria:

  <!-- -->

  1. . Urine bilirubin \< 1.25 times ULN (Upper Limit of Normal);
  2. . ALT and AST \< 2.5 times ULN;
  3. . CREA ≤ ULN;

Exclusion criteria:

• Secondary open-angle glaucoma (such as pigmentation syndrome, trauma, etc.) or angle-closure glaucoma.
• The best corrected visual acuity of either eye is less than 6/36;
• The mean derivation of visual field in either eye is less than - 22dB.
• Use of >2 topical (or any oral) IOP-lowering products at the baseline visit.
• Any ocular pathology in either eye that may have interfered with the ability to obtain visual field, disc imaging, or accurate IOP readings such as uveitis, refractive opacification;
• Eye drops such as neuroprotective therapies have been used in the past three weeks might affect this clinical study, for inclusion need 8 weeks of wash period.
• Pregnant or nursing women;
• Diabetes mellitus, definite impairment of liver and kidney function, or severe heart, liver or kidney diseases;
• In the last three months, ophthalmic surgery (including cataract surgery) has been performed
• Enrolled in other clinical study at the same time.
• Could not complete the study according to the requirements in this research .
• History of epilepsy or severe mental illness, including schizophrenia, bipolar disorder or severe depression