Only eye exams can detect most early symptoms of glaucoma


“It’s almost always silent,” says Shivani Kamat, MD, assistant professor of ophthalmology at UT Southwestern Medical Center and spokesperson for the American Academy of Ophthalmology. “Many people don’t notice vision loss themselves until they’ve lost more than 50 percent.”

One of the reasons peripheral vision loss is so sneaky is that our brain tends to “fill in” missing parts of the picture, says Thomas Brunner, president and CEO of the Glaucoma Research Foundation.

Only in its advanced stages does the most common type of glaucoma, open-angle glaucoma, affect central vision, which is needed for reading and many other daily tasks.

A less common form, called angle-closure glaucoma, can sometimes have dramatic immediate symptoms (see below).

But the best way to detect most early signs of glaucoma, as well as other eye problems, is to have regular eye exams, according to the Academy of Ophthalmology and the American Optometric Association. The US Preventive Services Task Force says more research is needed on glaucoma screening.

How eye exams can reveal signs of glaucoma

The American Academy of Ophthalmology recommends that all adults have at least one comprehensive eye exam before age 40 and regular exams thereafter. People over 65 should have exams at least every year or two, depending on the group. But eye doctors can urge high-risk people to get checked out sooner or more often.

African Americans over 40 are at particularly high risk for glaucoma. Overall, African Americans are six to eight times more likely than whites to have glaucoma, according to the CDC. Other risk factors include diabetes and a strong family history of glaucoma, he says.

“We usually tell patients that if they have a family history, [especially in] parent or sibling, their risk of developing glaucoma may be 10 times higher than if they didn’t,” says Thomas Samuelson, MD, eye surgeon and assistant professor of ophthalmology at the University of Minnesota.

Whether you’re having your eye exam with an ophthalmologist (doctor) or an optometrist (the eye health professional many people see for routine care), the exam should include several steps that can catch signs before -runners of glaucoma. These include tests for:

  • The appearance of your optic nerve. The defining characteristic of glaucoma is a damaged optic nerve, Kamat says. During a full exam, you should be given drops to enlarge your pupils, so the examiner can see the inside of your eye, including your retina and optic nerve.
  • The pressure inside your eye (intraocular pressure). Your eyes contain fluid that is constantly being drained and replenished. If for some reason fluid builds up, eye pressure may increase. This pressure can be measured with a variety of devices, including one that delivers a quick puff of air to your eye. The amount of eye pressure needed to damage the optic nerve differs from person to person, and some people with seemingly high pressure never develop glaucoma, Samuelson says. Glaucoma can also occur in people with seemingly normal blood pressure.
  • Yesour field of vision – or how well you can see from all angles. In the “quick and dirty” test often done during routine eye exams, the examiner wiggles a few fingers at various points in your field of vision to check for any gaps, Kamat says.

If warning signs appear, you may be referred to a specialist for further testing, Kamat says. Some people may hear that even though they don’t have glaucoma, they are “glaucoma suspects”, which means that the appearance of their optic nerve or eye pressure is concerning enough that they need to be followed closely for some time, she said.

The Other Type of Glaucoma: Knowing the Signs

In open-angle glaucoma, the most common type, the openings to the drainage channels at the front of the eye appear clear, although the channels may be blocked lower down, allowing fluid to collect and to the pressure to increase. But in angle-closure glaucoma, these openings are partially or totally blocked by the lower edge of the iris, the colored part of the eye. This less common condition can develop slowly, without immediate symptoms, much like open-angle glaucoma. An eye exam can detect signs of blockage, as well as damage to the optic nerve, Kamat says.

But sometimes a blockage suddenly develops and “eye pressure rises very quickly,” causing dramatic symptoms, Kamat says. It’s called acute angle-closure glaucoma, and it’s an eye health emergency, she says. Symptoms can include:

  • Severe eye pain
  • Eye redness
  • Headache
  • Blurred vision
  • See rainbows or halos
  • Nausea and vomiting

If you have these symptoms, your vision is at risk and you should go to the emergency room, Kamat says.

What happens after the diagnosis?

If you have open-angle glaucoma, with or without high eye pressure, the first treatment will usually be medicated eye drops that lower the pressure or a laser procedure to improve drainage. Laser treatments, which need to be repeated from time to time, can reduce or eliminate the need for drops in some patients, so they are increasingly being used as initial treatments, says Samuelson. Another newer option, he says, is an injected drug lozenge that can last up to six months.

When those approaches don’t work, surgery to open the drainage channels or implant a tiny stent may be the next step, he says. These surgeries can sometimes be done at the same time as the necessary cataract surgery, he adds.

People with angle-closure glaucoma also benefit from laser procedures and surgery, Samuelson says. A laser can be used to create a small hole in the iris and improve drainage. Cataract surgery alone can also help improve drainage, he says, because it involves the removal of an often thickened lens that sits behind the iris.

Treatment is crucial because as glaucoma progresses, loss of side vision can hamper everything from driving to descending stairs, Kamat says. Loss of central vision is even more debilitating. Once vision is lost, it does not return.

Brunner says no treatment cures glaucoma, but with effective management, “most people with glaucoma never go blind.”

Kim Painter is a contributing writer specializing in health and psychology. She writes frequently for AARP’s Staying Sharp and previously worked as a health reporter and columnist at USA today.

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