A New View of Normal Tension Glaucoma: Autoregulation and Systemic Blood Pressure

Glaucoma is an eye disease that leads to damage of the optic nerve, visual field loss and can progress to blindness. Traditionally, glaucoma and its treatment have been closely linked to intraocular pressures. In normal tension glaucoma, damage to the optic nerve occurs without any increase in intraocular pressure. Normal tension glaucoma most often occurs in the elderly and can lead to loss of sight and significant disability. Subjects with progressive visual field loss are often a highly motivated group of subjects, ready to take an active part in the treatment of their condition. Investigating the risk factors that contribute to the development of normal-tension glaucoma may shed light on the progression of the disease. Subjects with normal tension glaucoma will have their demographic and clinical characteristics recorded and their eyes examined at baseline, 6-months and 12 months. Subjects will wear an external blood pressure cuff for 48 hours that will record blood pressure every 30 minutes. This same blood pressure recording procedure will be performed at baseline, at 6 months, and at 12 months. At these same time intervals, visual fields will also be measured, as per routine clinical care, by the treating ophthalmologist. The results of the visual field testing will be recorded. The primary outcome of the study will be visual field abnormalities and their relationship to dips in systemic blood pressure. Results will be published and will be used as a base for future projects that may impact treatment and the understanding of risk factors of normal tension glaucoma.