Knowledge Base

Normal-tension glaucoma

Normal-tension glaucoma (NTG) is a form of glaucoma in which damage occurs to the optic nerve even in cases when intraocular pressure values are low and stable. Its causes aren't well known. It may be that the optic nerve is more sensitive or fragile, so even normal amounts of pressure can damage it. Periods of abnormally low blood pressure either from excessive reaction to blood pressure medicine or from having had severe blood loss may also play a role in its development. This type of glaucoma also could be caused, in part, by not enough blood getting to the optic nerve.