Is Normal Tension Different From High Tension: Genetic/Epidemiological Factors

Epidemiologic and genetic studies suggest that patients with normal tension glaucoma (NTG) have a different set of pre-disposing risk factors compared with patients with primary open angle glaucoma (POAG), high-tension open angle glaucoma (HTG) or ocular hypertension. In particular, Asians (especially Japanese) are at increased risk for NTG compared to other populations. Genetic studies of NTG families as well as NTG case/control samples have identified genes that could influence optic nerve susceptibility. A different set of genetic factors appear to influence risk of high-tension open angle glaucoma. These results suggest that the disease mechanisms underlying NTG may not be the same as those contributing to high- tension glaucoma.