Glaucoma is a group of eye conditions that damage the optic nerve and is often related to high pressure in your eye. But it can happen even with normal eye pressure. Glaucoma is one of the leading causes of blindness for people over the age of 60. Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is in its later stages. This is why it's important to have regular eye exams that include measurements of your eye pressure. If glaucoma is recognized early, vision loss can be slowed or prevented.