Glaucoma is an eye condition. Fluid normally moves in and out of different parts of the eye. In people with glaucoma, this fluid often does not flow correctly and pressure builds in the eye. The increased pressure may damage the main nerve in the eye. The 2 common types of glaucoma are acute and chronic glaucoma. Acute glaucoma happens suddenly and causes severe eye pain and rapid loss of vision. It is a medical emergency that requires immediate treatment. Chronic glaucoma, sometimes called primary open-angle glaucoma (POAG), develops slowly and painlessly over many years. Some people with POAG never develop noticeable vision problems, whereas others do. Glaucoma is diagnosed through a combination of tests, which often includes measuring the pressure in the eye by using an instrument called a tonometer. Treatment includes eye drop medications or surgery. The USPSTF wanted to determine whether doctors should screen patients for POAG. Screening means looking for a condition in people who have no signs or symptoms of it.