Glaucoma, a leading cause of blindness in the United States, has very few symptoms in its early stages, but catching the disease early is crucial to saving your eyesight. Here’s how you can detect it.
Glaucoma, a leading cause of blindness in the United States, is considered a so-called silent disease — it has no obvious symptoms early on. In fact, as many as half of all people with glaucoma do not know they have the condition, says ophthalmologist Alberto Martinez, MD, a spokesperson for the American Academy of Ophthalmology. Regular eye exams are important for diagnosing and treating glaucoma — and early treatment is key to saving eyesight.
Glaucoma is actually a group of diseases that can harm the optic nerve, the part of the eye that transmits images to the brain. In most cases, glaucoma occurs when there is an increase in the normal fluid pressure inside the eye. That pressure can damage the optic nerve, causing vision loss and blindness.
Doctors don’t know what causes glaucoma, but they have noted certain risk factors:
Being 65 years of age or older
Having a family history of glaucoma
Being of African, Asian, or Spanish descent
Being nearsighted or farsighted
Having had a past eye injury
The Types of Glaucoma
Open-angle glaucoma is the most prevalent type of this eye disease, but it’s not the only one:
Open-angle glaucoma. In healthy eyes, eye fluids flow into, out of, and around the eye at the open angle where the cornea and iris meet; this angle acts like a drain. Open-angle glaucoma occurs when the fluid doesn’t flow out easily from this drain, causing a build-up of fluid pressure in the eye. That pressure can damage the optic nerve, leading to decreased peripheral (side) vision and vision loss. In the early stages of the disease, people with this type of glaucoma have no symptoms — no pain or changes in vision. They may not know they have it until the disease progresses and their peripheral vision becomes affected. Over time, they lose more of their side vision and can eventually become blind.
Normal-tension glaucoma. Sometimes damage to the optic nerve can occur in people with normal eye pressure. Doctors are not sure why this happens, but risk factors for normal-tension glaucoma, also called low-tension glaucoma, include a family history of any type of glaucoma or a history of cardiovascular disease.
Angle-closure glaucoma. This rare type of glaucoma happens when the iris blocks the drain part of the eye. Because eye fluid cannot drain out, pressure can build very quickly, leading to vision loss. Symptoms of angle-closure glaucoma include headache, eye pain, nausea, redness of the eye, and blurred vision. Anyone with these symptoms should seek immediate medical attention. Without treatment, you can lose your sight in just one or two days.
Congenital glaucoma. This rare, sometimes inherited, type of glaucoma is present at birth. A defect in the drainage system of the eye builds fluid pressure inside the eye, damaging the optic nerve. Symptoms of congenital glaucoma are a cloudy-looking cornea, sensitivity to light, and excessive tearing.
What Is Secondary Glaucoma?
Secondary glaucoma can develop because of an eye injury, eye surgery, inflammation, certain eye tumors, or advanced cataracts. This type of glaucoma can also be a side effect of some drugs, such as corticosteroids. Types of secondary glaucoma include:
Pigmentary glaucoma. Pigment granules from the back of the iris break off and block eye drainage.
Pseudoexfoliative glaucoma. A flaky material peels off the outer layer of the eye’s lens and impedes proper drainage.
Traumatic glaucoma. Caused by an eye injury, this glaucoma can occur immediately afterwards or years later.
Neovascular glaucoma. Often linked to diabetes, neovascular glaucoma is marked by the abnormal formation of blood vessels that grow over the iris, blocking drainage.
Iridocorneal endothelial syndrome. This rare form of glaucoma usually occurs in one eye, as cells from the back surface of the cornea spread over its drainage area.
How Glaucoma Is Diagnosed
Because glaucoma symptoms are usually not noticeable until the disease has progressed, early detection and screenings are essential. “Glaucoma can be such a gradual thing that you could be asymptomatic until you lose 80 percent of your vision,” says Dr. Martinez.
Adults who have no signs or risks for eye disease such as glaucoma should get a baseline eye screening exam starting at age 40. If you have any risk factors for glaucoma, screenings should be done every two years, regardless of your age. People age 65 and older should see their eye doctor every one to two years to check for glaucoma and other eye diseases, because risk increases with age.
During a glaucoma exam, your doctor will conduct a tonometry test to measure the pressure inside the eye, as well as an ophthalmoscopy to look at the inside of the eye — the optic nerve in particular. The eye exam may also include a visual acuity test to determine how well you see at various distances, a visual field test to measures your peripheral vision, and a pachymetry test, which measures the thickness of your cornea.
Ways You Can Manage Glaucoma
In the early stages of glaucoma, medication in the form of eye drops or pills can help. Medication can lower pressure in the eye by causing the eye to make less fluid or by helping fluid drain from the eye.
If medication doesn’t help, doctors may recommend surgery. One type of surgery for glaucoma is laser trabeculoplasty, in which a laser is used to stretch the drainage holes to help fluid drain better. If laser surgery isn’t effective, or if the problem occurs again over time, doctors may suggest conventional surgery. This procedure is called filtering microsurgery and involves making a new drainage hole for fluid to leave the eye.
With early detection and treatment, many patients with glaucoma can retain their eyesight and ward off vision impairment.