Glaucomatous damage not only occurred to retinal ganglion cells in the eyes, but went across optic nerves, visual chiasm, lateral geniculate nucleus (LGN) and finally the visual cortex; the neural degenerations could be identified through the whole visual tract, which suggests the central nerve system may play a vital role in the progression of glaucoma. The investigators used MRI to investigate changes of visual pathway in vivo.

Inclusion Criteria:

• Primary open angle glaucoma diagnosed on the basis of glaucomatous optic disc cupping ratio (in particular, thinning of the inferior and/or superior rim, cup-to-disc ratio asymmetry of >0.2)
• matching glaucomatous visual field defects (European Glaucoma Society (2008) Perimetry )

Exclusion Criteria:

• optic neuropathy
• neurological disorder
• other diseases and use of systemic medications which affect optic nerve or the visual field underwent complete eye examination and visual-field testing.

All subjects recruited from the Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Clinical ophthalmic assessments including measurement of visual acuities, intraocular pressure, slit-lamp microscopes and funduscopes examinations, cup-to-dick ratio (CDR) evaluation, visual field test [Octopus 101 Automated Perimeter, Haag-streit, Switzerland. Program G2], optical coherence tomography for retinal nerve fiber layer thickness(RNFLT) around the optic disk[Stratus OCT，Carl Zeiss Meditec, Dublin, CA .Scan Type :Fast RNFLT 3.4, Scan Length: 10.87mm].