Nick Strouthidis MBBS MD PhD FRCS FRCOphth FRANZCO

Do Patients With Glaucoma Always Have High IOP?

Up to 40% of people with glaucoma never have a high IOP reading (usually called normal tension glaucoma). This is, in fact, the most common presentation of glaucoma in people of Japanese or Korean origin. Normal tension glaucoma is usually considered a variant on the spectrum of primary open angle glaucoma.

Certain other risk factors may be associated with the development of normal tension glaucoma:

• History of migraine

• History of Raynaud's Phenomenon (cold hands and feet)

• History of significant blood loss

• Very low blood pressure during sleep or when lying flat

All of these risk factors are assumed to be related to a predisposition to reduced blood flow to the optic nerve, which may contribute (along with IOP) to the development of glaucoma in people with normal tension glaucoma.