The early symptoms associated with chronic open angle glaucoma, the most common type, are usually unnoticeable. At first, in most cases, the build up of pressure is gradual without any discomfort or pain. Most people do not detect a change in their vision until substantial sight loss has occurred. Certain parts of peripheral (side) vision are affected first with the top, sides, bottom of the field of vision becoming decreased. Later, in the course of the disease, central vision becomes affected, mild headaches and difficulty with night vision might be experienced. And, if left untreated, total blindness will result.