-Inclusion Criteria:  New NTG patients naïve to treatment. Patient with 360 degrees open angles on gonioscopy. Patients with glaucomatous optic neuropathies (GON). Patients with three repeatable visual field defects over two visits. Subjects must have IOPs ≤ 21 mmHg and no recorded IOPs > 21 mmHg at any time.  Glaucomatous optic neuropathy and visual field criteria:  Category 1 and 2 of the glaucoma diagnostic criteria of the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) will be adopted in this study.  ISGEO Category 1 classification of glaucoma:  Reliable and repeatable visual field defects consistent with a glaucomatous optic neuropathy, and either a vertical cup-disc ratio (VCDR) at the 97.5th percentile of the normal population (about 0.7 VCDR), or VCDR asymmetry between the right and left eyes at the 97.5th percentile of the normal population (i.e., about 0.2).  ISGEO Category 2 classification of glaucoma:  Visual field results are not definitive or are unattainable due to patient inability to perform an adequate quality test, and optic disc has VCDR of at the 99.5th percentile of the normal population (i.e., VCDR of about 0.9) or VCDR asymmetry between the right and left eyes at the 99.5th percentile of the normal population (i.e a CDR asymmetry of about 0.3).  -Exclusion Criteria  Patients with IOPs greater than 21 mmHg at any previous point in time Patients with corneal pathology Previous ocular surgery in the past 6 months Patients with any other types of glaucoma other than NTG Patients who are unwilling or unable to follow-up for a 3-month period Patients with systemic conditions where a non-glaucomatous optic neuropathy cannot be ruled out. Subjects who are pregnant, breastfeeding, or considering becoming pregnant Subjects who could be pregnant will be screened for pregnancy thus: Those who are not pregnant nor considering becoming pregnant and are not on any birth-control at the time of recruitment will be excluded from participation because of the risk of pregnancy unknown to the patient at the time of recruitment.