Is Normal Tension Different Than High Tension Glaucoma

Open angle glaucoma (OAG) the second leading cause of irreversible blindness in the United States1, comprises 2 major syndromes: primary open angle glaucoma (POAG) and normal pressure glaucoma (NPG). POAG is a disease generally characterized by a clinical triad which consists of 1) elevated intraocular pressure (IOP); 2) the appearance of optic atrophy presumably resulting from elevated IOP; and 3) a progressive loss of peripheral visual sensitivity in the early stages of the disease, which may ultimately progress and impair central visual acuity2. Primary open angle glaucoma affects approximately 0.5% of the American population3 and occurs in 1.3% of white and 4.7% of black Americans over the age of 40 (1.6 million persons)4. Studies have indicated, however, that a surprisingly high percentage of patients with open-angle glaucoma have findings identical to those of POAG but with a singular exception; namely, that the IOP has never been demonstrated to be elevated.