Blood viscosity in primary open-angle glaucoma.

To determine whether hemorrheologic factors play a part in optic nerve cupping and visual field loss in glaucoma, blood viscosity was measured at three shear rates in 27 patients with primary open-angle glaucoma and 18 healthy control subjects matched for sex, mean arterial blood pressure and smoking habits. The study was conducted between 1984 and 1986. The mean viscosity was significantly higher in the glaucoma group than in the control group at all three shear rates. The possible relevance of raised blood viscosity as a causal factor in optic nerve cupping in patients with glaucoma is discussed.