Clinical features 1. Open-angle glaucoma a. Painless, increased IOP (may be the only sign), characteristic changes in optic nerve b. Progressive and insidious visual field loss (usually sparing central vision until end-stage disease) 2. Closed-angle glaucoma a. Red, painful eye b. Sudden decrease in visual acuity (blurred vision), seeing “halos,” markedly elevated IOP c. Nausea and vomiting (common), headache d. Involved pupil is dilated and nonreactive (in mid-dilation)