Glaucoma: Symptoms, Eye Pressure, Screening and When It Is an Emergency

What it involves

The MedlinePlus encyclopedia explains that glaucoma is a group of eye conditions that can damage the optic nerve, the nerve that sends images to the brain. Most often the damage is caused by increased pressure in the eye. A complete eye exam by an eye doctor is the only way to diagnose it.

Who this is for

• Adults with a parent or grandparent who had open-angle glaucoma.
• People who use steroid medicines, or who have diabetes or a past eye injury.
• Patients who have not had a complete eye exam in years and want to know when to book one.
• Anyone who has noticed blind spots or narrowing of side vision, or halos around lights.

What to expect

• Questions about family history, medicines, diabetes, eye injuries and changes in your vision
• A review of your risk factors and blood sugar, which the practice can check with blood work
• Advice on when your next complete eye exam is due
• A referral to an eye doctor for the eye pressure check, dilated exam and visual field testing

Call 911 or go to the ER for an eye attack

MedlinePlus says severe eye pain or a sudden loss of vision needs immediate medical help, because these may be signs of closed-angle glaucoma. It calls an acute angle-closure attack a medical emergency and warns that you can become blind within a few days without treatment. Other signs are cloudy or steamy vision, rainbow halos around lights, nausea and vomiting, a red eye and an eye that feels swollen. Do not wait for a routine appointment, and the blurry vision guide explains other vision changes.

The quiet kind

Open-angle glaucoma is the most common type. The encyclopedia says the cause is unknown, that pressure rises slowly and you cannot feel it, and that most people have no symptoms. The pressure pushes on the optic nerve and causes blind spots, and the main loss is slow narrowing of side vision, sometimes called tunnel vision. Advanced glaucoma can lead to blindness. It tends to run in families, and risk is higher if a parent or grandparent had it and in people of African descent.

Other types and what raises the risk

Closed-angle glaucoma happens when fluid is suddenly blocked, and dilating eye drops and certain medicines may trigger an attack. Secondary glaucoma has a known cause such as corticosteroid medicines, inflammation inside the eye, diabetes or an eye injury, and congenital glaucoma is present in babies. Blood sugar control matters for eye health, and the high blood sugar guide explains symptoms and checks. Dry, irritated eyes are a separate issue, covered in the dry eye guide.

How it is diagnosed

The encyclopedia says the only way to diagnose glaucoma is a complete eye exam. Your eye doctor checks eye pressure with tonometry, usually dilates your pupil, and looks at the optic nerve. Because pressure varies through the day and can be normal in some people with glaucoma, other tests may be used, including gonioscopy, optic nerve imaging, a visual field test and a slit-lamp exam. These are done by an eye doctor, so your primary care visit ends with a referral rather than a pressure check.

Treatment and keeping your sight

The goal of treatment is to reduce eye pressure. MedlinePlus lists eye drops, laser treatment, pills and, when those do not work, surgery to open a new channel for fluid, and for an acute attack drops, pills and medicine through a vein, sometimes with a laser to make a new channel. Open-angle glaucoma cannot be cured, but the encyclopedia says you can manage it and keep your sight by following your eye doctor's directions. All of this is eye specialist care.

How often to have an eye exam

The encyclopedia says you cannot prevent open-angle glaucoma and that there is uncertainty about the best way to screen for it, but a complete eye exam can find it early when it is easier to treat. It says all adults should have a complete eye exam once during their 20s and twice during their 30s, and sooner if you are at risk. A yearly physical is a good time to ask, and the annual physical guide describes what to bring.

Sources

• MedlinePlus Medical Encyclopedia: Glaucoma
• MedlinePlus: Glaucoma