Glaucoma Symptoms, Testing and Diagnosis

Angle-closure glaucoma

This less common form of the disease is caused when “the iris bulges forward and blocks the drainage angle in the eye,” says Sayoko Moroi, chair and professor of ophthalmology at the Ohio State University’s Havener Eye Institute. When the drainage angle gets completely blocked, eye pressure rises quickly. You might also hear this referred to as closed-angle glaucoma or narrow-angle glaucoma. 

Glaucoma testing

In most cases of glaucoma, patients notice no symptoms. Testing during a comprehensive, dilated eye exam will reveal if there is a concerning rise in your eye pressure, loss of peripheral vision or damage to the optic nerve that indicates glaucoma. You will find out your glaucoma test results in the office during your appointment. Here is what vision specialists use to diagnose glaucoma, according to the Glaucoma Foundation:

• Specific eye measurements. The tonometer measures your intraocular pressure (IOP), or the pressure in your eye. The test may include a brief puff of air onto the eyeball or applying a pressure-sensitive tip near your eye. High IOP alone doesn’t diagnose glaucoma, according to the National Eye Institute. The pachymeter measures the thickness of your cornea, which plays an important role in glaucoma risk and diagnosis. This test can help confirm a glaucoma diagnosis, as well as the type of glaucoma you have, per the Glaucoma Research Foundation. There are a couple of types of pachymetry, one of which is no-contact and uses imaging to take corneal measurements. Another requires numbing drops before a handheld device touches your cornea, taking measurements.

• Glaucoma visual field test. The earliest symptom of open-angle glaucoma is usually some loss of peripheral vision, which can only be found through measurable findings at an eye exam, Iwach says. In this test you look straight ahead at a fixed point and tell your doctor when you see a light or object off to your side.

• Ophthalmoscopy. This test allows your vision provider to examine the back of your eye, including your optic nerve, for evidence of damage from glaucoma. Other names for this test include funduscopy, and there are also different types of ophthalmoscopy, such as slit-lamp ophthalmoscopy. This test is performed by shining a light into dilated eyes through a magnifying lens. This gives your eye care professional a straight line of sight to your optic nerve.

• Gonioscopy. This test allows your provider to visualize the inside of your eye to ensure fluid is draining out of the eye properly. Your provider needs to place a special mirrored contact lens into each eye to see its drainage angle. To minimize discomfort, numbing drops will be applied to your eyes before these contacts are placed. Next, your eye care professional will shine a light into the eye, using the mirror to look at the drainage angle.

• Optical coherence tomography. An OCT test for glaucoma first involves dilating your eyes. Next, a machine takes pictures of your eye, which doctors use to examine the health of your optic nerve, per NYU Langone Health.

Glaucoma risk factors

Everyone is at risk for glaucoma, but some folks are more vulnerable, such as people who:

• Are African American, Asian American or Hispanic
• Are over age 40
• Take steroids
• Have a family history of glaucoma
• Have a past eye injury
• Have diabetes, high blood pressure, heart disease or sickle cell anemia
• Smoke
• Wear glasses or contacts to correct nearsightedness or farsightedness 

Glaucoma symptoms

Alarmingly, there are often no noticeable symptoms of glaucoma, which is why getting regular, comprehensive eye exams is so critical in detection. (You cannot test for glaucoma at home.)

However, people with the less common angle-closure glaucoma can experience symptoms of an acute attack, including:

• Headache
• Nausea and/or vomiting
• Seeing rainbow-colored rings or halos around lights
• Severe eye pain
• Sudden blurry vision

Anyone with these symptoms should be checked by their ophthalmologist or vision care specialist as soon as possible; angle-closure glaucoma can cause irreversible vision loss if not treated right away. 

Glaucoma treatment

Regular checkups and proper glaucoma treatment can help slow or prevent vision loss, especially if symptoms are detected early. “There is a risk of losing significant vision from the disease. But for most people, the earlier we can catch it, the more we can save.... Early diagnosis is paramount,” Iwach says. 

While glaucoma damage cannot be reversed, Iwach says, most patients can typically control and manage the disease with medicated eye drops, in-office laser treatment or surgery.

Medication for glaucoma

Prescription eye drops, used every day, are the most common way to lower eye pressure and control glaucoma. Your doctor may prescribe one, or more to be used in combination. Some tackle glaucoma by reducing the amount of fluid your eye produces; others increase the amount of fluid that drains out of the eye. 

Prostaglandin analogs are the treatment of choice for many patients. They lower pressure by increasing the outflow of fluid in the eye. This category includes latanoprost (Xalatan), travoprost (Travatan), bimatoprost (Lumigan) and latanoprostene bunod (Vyzulta).  

Other drugs, Rho kinase inhibitors, which include netarsudil (Rhopressa), also lower IOP by helping with the outflow of fluid. Rocklatan, another option, contains netarsudi and latanoprost, a combination that can be very effective.  

Another advancement in medicated eye drops is the development of a preservative-free latanoprost, Iwach says. Preservatives, which are added to formulas to prevent infection, are known to cause eye irritation for some folks. As people get older, it’s not uncommon to have glaucoma and dry eye. “For these patients, the impact of preservatives can be more pronounced,” he says. Preservative-free formulations allow people to deliver the medication into their eye without this unpleasant side effect. 

Though prescription eye drops can be effective, they’re not necessarily practical. Some patients may forget to use them; others find it challenging to get them into the eye (a particularly tricky endeavor for people with shaky hands). Durysta is a dissolvable pellet, injected into the eye during a five-minute in-office procedure; it slow-releases IOP-lowering medication and is designed to last for up to six months.

Glaucoma surgery

Laser surgery

The most common type of laser surgery performed for open-angle glaucoma is selective laser trabeculoplasty (SLT), in which a laser opens clogged channels in the trabecular meshwork to increase the outflow of fluid. 

SLT is typically used in patients whose glaucoma is being controlled by eye drops, but it can sometimes be used in place of medication. “There has been data to suggest that there are side effects with medications taken every day and they are inconvenient for patients, and that maybe we should consider doing laser treatments before we even start drops,” Iwach says. “There was an interesting study out of the [United Kingdom], which recommended considering doing selective laser trabeculoplasty treatment — which can reduce pressure in approximately 80 percent of patients — and delay the need for eye drops for some patients.”  

A follow-up study published in 2023 found that after six years, the SLT treatment was more effective in preventing disease progression compared to eye drops and reduced the need for surgery. “The past 10 years, there’s been a gradual migration to using lasers earlier in the treatment regimen, though they are not appropriate for everyone. Some patients are happy with a daily eye drop,” Iwach says.  

Non-contact lasers

When doing SLT, eye doctors use a gonioscope (an instrument including a contact lens placed directly over the cornea). Though the procedure isn’t painful, there is a certain, well, ick factor. Direct selective laser trabeculoplasty (DSLT) is performed through the limbus (the border between the cornea and the sclera, the white of the eye) and doesn’t involve a lens, so there’s no contact with the surface of the eye. What’s more, it takes less time to perform than selective laser trabeculoplasty: “about a second or less for the whole treatment,” Iwach says. Alcon, a company that produces vision care products, has newly acquired the technology, which has clearance from the Food and Drug Administration, and expects to make these devices available to physicians by the end of 2024.

Traditional surgery

If eye drops and laser treatments aren’t doing the trick, or you can’t handle the side effects from medications, then your ophthalmologist may recommend conventional surgery to create a new way for fluid to leave the eye. In a trabeculectomy, an opening is made in the sclera to allow excess fluid to drain out of the eye and into a small reservoir, which is hidden under the upper eyelid.

From there, the fluid is absorbed by tissue around the eye. Implant devices also increase the outflow of fluid. A tiny drainage tube is inserted into the front chamber of the eye, leading back behind the eye, where a small collection area is created to drain off excess fluid. 

The standard treatment for closed-angle glaucoma is laser peripheral iridotomy. “A laser is used to make a tiny hole in the iris to help release fluid behind the iris,” says Anne L. Coleman, M.D., a professor and chair of the UCLA Department of Ophthalmology. These procedures are very comfortable and are usually done at the ophthalmologist’s office or an outpatient facility. 

Microsurgery

Several techniques and devices are being used to address glaucoma that don’t have the complexity or carry the risks of traditional surgery, Iwach says. These newer, faster, less invasive procedures, called MIGS (short for micro-invasive glaucoma surgeries), use microscopic equipment and tiny incisions. These procedures are performed in an operating room and can take as little as five minutes. Because these procedures aren’t as effective in lowering eye pressure, however, they’re more appropriate for those in the early-to-moderate stage of the disease. Talk to your doctor and insurance company about coverage. 

MIGS can be done as a standalone procedure but are more commonly done at the time of cataract surgery. “When patients undergo cataract surgery we open the eye, take the cataracts out and put lenses in,” Iwach says. “That gives us opportunity to have access to the trabecular meshwork.”

Performing a two-in-one surgery can also cut down on complications. “One of the risks when doing eye surgery is that the incision can create a potential pathway for bacteria and infection,” Iwach says. “But here you’re making a smaller incision, so there’s less of a chance of that happening.” If you’re going to have cataract surgery, it may be worth asking if your doctor would consider doing one of these procedures at the same time.

Glaucoma prevention

It’s scary stuff, but here’s the good news: If glaucoma is diagnosed in time and treated, you may be able to stop additional vision loss and prevent blindness. “The prognosis is excellent, but people often take their eyes for granted and forget about them until they notice symptoms,” Coleman says. “That’s why it’s important to get examined to assess what your risk is.”

The American Academy of Ophthalmology recommends that adults, beginning at age 40, get regular comprehensive eye exams with an ophthalmologist. People who are 65 and older should get an eye exam every one to two years. Those with chronic conditions such as diabetes or high blood pressure, known eye diseases or other risk factors may need to get checked more often.

Editor's note: This article, originally published on January 7, 2019, was updated to reflect new medical developments.