Perimetry (or visual field testing) is a vision test used to evaluate a patient's peripheral vision. It involves a patient fixating on a central target and pressing a button when they see a spot of light in their peripheral vision. It is an important way of deciding whether Glaucoma is progressing or not. Next generation virtual reality (VR) technologies offer an exciting new way of conducting perimetry in either a clinical or home environment, allowing more affordable and more frequent monitoring of disease progression in glaucoma, and an easier and more comfortable experience for patients. The investigators propose to create a perimetry test using a commercially available head mounted display for VR, and to assess its accuracy in glaucoma patients in relation to standard automated perimetry.