Eye pain doesn't always signal a serious problem. It also doesn't always mean you have a problem with your eyes. Sometimes another type of health condition is to blame. Infection Eye infections can be painful and serious. For instance, bacterial keratitis is an infection that needs treatment quickly because it can eventually cause blindness. It causes sudden eye pain, watery eyes, and changes in vision. Cellulitis is another eye infection that causes pain. The eye swells and turns red. Cellulitis affects vision and may bring on a fever. It needs treatment to prevent spreading and causing serious damage to the eyes. Conjunctivitis (pink eye) is a very common eye infection. It's especially common in children. The infection causes redness, watering eyes and eye irritation and discomfort. Injury Eye injuries can cause eye pain, too. The source might be a cut, scrape or ulcer that forms on the cornea of the eye. Eye injuries can cause keratitis, an inflammation of the eye. This can happen from wearing contact lenses too often. Pain from an eye injury should go away once the injury heals. Glaucoma Glaucoma also can be a source of eye pain. This is a serious eye disease. It's caused by fluid that builds up in the eye. This increases pressure inside the eye. Some types of glaucoma cause sudden, severe attacks that reduce vision and cause intense pain in the eye. To preserve your eyesight, glaucoma needs medical treatment. Autoimmune Disorder Eye pain sometimes signals problems elsewhere in your body. One cause is an autoimmune disorder. Common ones are lupus, rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis, Graves' disease (a thyroid condition) and inflammatory bowel disease. These diseases occur when your immune system attacks a healthy part of your body, thinking that it's something harmful. Some autoimmune disorders attack the eyes and cause pain. If you have an autoimmune disorder, you may experience a condition called uveitis. That's inflammation of the part of the eye called the uvea. Uveitis causes pain, redness and vision loss. It should always be checked by a doctor. Multiple sclerosis affects the nervous system. The immune system attacks the brain and spinal cord. It often affects the optic nerve, which is the nerve in the eye. Eye pain and vision changes are common in people with multiple sclerosis. These are often the first warning signs of the disease. Cluster and Migraine Headaches Some types of headaches cause eye pain. For instance, cluster headaches are known for causing intense pain around or in one eye or on one side of the head. Migraine headaches also may cause pain around the eyes. If you get the type called migraine with aura, you may notice changes in your vision. You might see spots or wavy, zigzag patterns. Certain medications can treat and even prevent migraines. Lifestyle changes, such as regular sleep and eating schedules, also may help.