Glaucoma isn't one disease. Instead, it's a group of diseases that cause damage to the optic nerve. In most cases, this damage is the result of increased pressure within your eye. As the optic nerve deteriorates, the patient gradually loses the ability to see to the side (peripheral vision). In time your central vision may begin to decrease as well. If glaucoma isn't treated, it eventually may lead to total blindness. In fact, glaucoma is the second most common cause of blindness. That's because glaucoma often gives no warning sign until permanent damage has already occurred. In most cases the onset is so gradual you're not aware you've lost some of your peripheral vision.

There are several types of glaucoma, including primary open-angle glaucoma, angle-closure glaucoma, congenital glaucoma and secondary glaucoma. Primary open-angle glaucoma develops slowly and painlessly when normal eye fluid known as aqueous humor doesn't drain properly, causing pressure to build up within your eye. It accounts for 60 percent to 70 percent of all glaucoma cases. About 10 percent of people with glaucoma have angle-closure glaucoma, which occurs suddenly and often causes dramatic symptoms. This type of glaucoma is a medical emergency and requires immediate treatment. A much smaller number of people have congenital glaucoma, which is present at birth, or secondary glaucoma, which results from trauma, chronic steroid use or disease. Still, the news about glaucoma is encouraging. When it's detected and treated early, glaucoma need not cause blindness or even severe vision loss for most people.

The signs and symptoms of glaucoma vary, depending on the type of glaucoma. Primary open-angle glaucoma Primary open-angle glaucoma often goes undetected for years. Pressure within the eye increases gradually, with no early warning signs. But eventually, you lose more and more of your side vision until only a narrow section of your visual field remains clear. This type of glaucoma tends to affect both eyes, although you may have symptoms in just one eye first. In addition to reduced peripheral vision, the signs and symptoms of primary open angle glaucoma may include: • Sensitivity to glare • Trouble differentiating between varying shades of light and dark Angle-closure glaucoma Attacks of angle-closure glaucoma often develop suddenly, but you also may have preliminary warnings weeks or even months ahead of a severe attack. Glaucoma attacks usually occur in the evening when the light is dim and your pupils are dilated. The pain may be very severe and cause vomiting. Other signs and symptoms of acute glaucoma may include: • Blurred vision, usually in just the eye involved • Halos appearing around lights • Reddening of your affected eye Congenital glaucoma This type of glaucoma is usually present at birth, but signs and symptoms — such as eyes that seem cloudy, are often watery or teary or are sensitive to light — may not appear until an infant is a few months old.

You may not need any treatment if your eye pressure is only slightly elevated and there's no damage to your optic nerve. Instead, your doctor may choose to monitor your condition with regular eye exams. But if you have signs of optic nerve damage, treatment can help slow its progression. Unfortunately, it's not currently possible to reverse damage that has already occurred. Most people have good results with glaucoma medication, but some may need surgery instead. Medications for glaucoma Most glaucoma medications are applied directly to your eyes in the form of drops, although a few may be taken orally. Because a portion of the drops may be absorbed into your bloodstream, you sometimes may have side effects unrelated to your eyes. In addition, some medications may lose their effectiveness over time. In that case, you may need to change or add medications or have surgery to control your glaucoma. It's not always easy to use glaucoma medication as directed. Drops usually need to be applied several times each day, and if you're using more than one medication, you need to wait at least 5 to 10 minutes between applications. This rigorous schedule can sometimes seem time-consuming and confusing. Furthermore, because glaucoma rarely causes symptoms in its early stages, you may not notice any change in your vision when you start using medication. Still, it's extremely important to follow your treatment plan exactly as your doctor prescribes. Skipping even a few doses of medication can cause your glaucoma to become worse. If you have trouble with your treatment plan, tell your doctor. Surgery for glaucoma When medications aren't effective or well tolerated, surgery may be an option. Keep in mind that surgery doesn't cure glaucoma. As a result, you may need to keep using antiglaucoma medications even after surgery. In some cases, you may need a second operation. Laser surgery (trabeculoplasty) In this procedure, your doctor uses a beam of high energy light to shrink part of the meshwork of your eye's drainage angle. This causes other areas of the meshwork to stretch, which helps aqueous fluid drain more easily. Laser surgery, which usually takes between 10 and 20 minutes, will likely be performed in your doctor's office under local anesthesia. Following surgery you should have almost no discomfort, but you'll need to continue taking eyedrops, at least for a time, and you may need more surgery within 5 years. In some cases intraocular pressure actually may increase following laser surgery. In most cases this is temporary, but sometimes the rise in pressure may be permanent, leading to further vision loss. Trabeculectomy In this procedure a surgeon creates a new drainage pathway for fluid in the white part of your eye (sclera) using traditional surgical techniques. Many people who have had this type of surgery no longer need eyedrops. But there are also risks. In some cases, scars may form that close the drainage channels. This is a particular problem in young people, blacks and people who have had cataract surgery. Drainage implants This may be an option for adults when other treatments have failed as well as for infants and children. In this procedure a small silicon tube is inserted in your eye to help drain aqueous fluid. Possible complications include the clouding of the lens of your eye (cataracts) and implant failure. Medications and surgery for acute glaucoma Doctors may administer several different medications during an attack of acute glaucoma in an effort to reduce eye pressure as quickly as possible. Once your eye pressure is brought under control, you may have an emergency operation known as an iridotomy to create a drainage hole in your iris. This surgery is now almost exclusively performed with lasers, which allow specialists to form an opening without making an incision in your eye. Laser iridotomy is an outpatient procedure that avoids many of the risks of traditional surgery. After treatment you can usually resume your normal activities right away.