Systemic Glutathione Level in Normal Tension Glaucoma

Patients were included in the normal tension glaucoma group according to the following criteria.

Inclusion Criteria (normal tension glaucoma group):

• Clinical Diagnosis of Normal Tension Glaucoma: Patients underwent diurnal IOP phasing and were diagnosed as having normal tension glaucoma(IOP always lesser than 22 mm Hg by applanation tonometry), glaucomatous optic disc cupping on fundoscopic examination, open anterior chamber angles by gonioscopy(Schaffer grade III or more), and repeatable VF defects consistent with the diagnosis of glaucoma, according to results obtained with program 24-2 of the Humphrey Field Analyzer.
• Must be able to provide intravenous blood sampling

Exclusion Criteria (normal tension glaucoma group):

• Narrow iridocorneal angles
• Any evidence of secondary open-angle glaucoma
• Any other ocular disease except cataract
• History of previous intraocular surgery including cataract
• Any other systemic disease except hypertension

The control group was composed of age-matched healthy volunteers who had neither glaucoma nor other ocular diseases such as cataract, diabetic retinopathy or age related macular degeneration. The control group did not show any glaucomatous optic disc cupping on fundoscopic examination or visual field defects with program 24-2 of the Humphrey Field Analyzer. The healthy volunteers in the control group must be able to provide intravenous blood sampling.

Exclusion criteria for both groups:

• Smoking
• History of any chronic systemic disease with presumed low glutathione levels, including autoimmune diseases, alcoholic liver disease, cancer, and diabetes mellitus.