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Early Symptoms of Glaucoma

Contributor: David S. Friedman, MD, PhD, MPH
8 minute read
A smiling man wearing glasses.

Glaucoma is the second leading cause of blindness in the world. People can go years without detecting the condition; they typically experience symptoms only when vision loss becomes permanent.

According to David S. Friedman, MD, PhD, MPH, a Mass General Brigham glaucoma specialist, about 90% of people in developing countries are unaware they have the disease. Even in the United States, about half of people with glaucoma don’t know they have it.

“We have come a long way in our ability to diagnose and treat glaucoma from when I first began practicing medicine,” says Dr. Friedman. “But much work needs to be done, especially when it comes to catching the condition sooner.”

Dr. Friedman serves as director of the Glaucoma Service at Mass Eye and Ear. He explains how patients can identify glaucoma signs and symptoms and what treatments can stop or prevent further damage.

What is glaucoma?

The optic nerve connects the eye to the brain. If the nerve is damaged, the message from the eye is not recognized. Glaucoma, a form of damage to the optic nerve, can lead to vision loss, or blindness, if left untreated.

Glaucoma risk factors

While glaucoma can develop at any age, it is much more common in older adults. Those at an increased risk of glaucoma include people who:

  • Are over age 60
  • Have a first-degree relative with glaucoma
  • Have had a major eye injury, one where bleeding occurs at the front of the eye. This usually happens after being hit in the eye directly, like from a punch or a car accident.
  • Are highly near- or far-sighted

Race and ethnicity elevate risk, too. African Americans and Hispanic Americans are much more likely to develop glaucoma than white people.

“While many people might just think of high eye pressure when they think of glaucoma, about half of all glaucoma cases occur in eyes with pressure in the normal range. That’s why checking the health of the optic nerve is so crucial.”

David S. Friedman, MD, PhD, MPH
Glaucoma Specialist
Mass General Brigham 

What is the first sign of glaucoma?

Patients rarely notice glaucoma signs and symptoms until it is too late. No current treatments can reverse damage from the condition, let alone vision loss.

Two main types of glaucoma exist: 

1. Primary open-angle glaucoma symptoms

Primary open-angle glaucoma is the most common type of glaucoma. 

The condition develops slowly, and few obvious symptoms occur at its earliest stages. While experts are unsure of what causes this type of glaucoma, they suspect eye pressure plays a role. Too much pressure presses liquid inside the eye against the optic nerve, damaging it.

Early symptoms include:

  • Clouded vision

  • Difficulty seeing when lighting conditions change or in low-light situations

In later stages of the disease, patients may experience:

  • Loss of side vision

  • Damage to central vision

2. Angle-closure glaucoma symptoms

The blue or brown ring of the eye, known as the iris, controls how much light enters the eye. The iris can sometimes block fluid draining from the eye. When this happens, angle-closure glaucoma occurs.

While most people with angle-closure glaucoma do not experience symptoms, some can experience sudden spikes in eye pressure.

High eye pressure symptoms

A sudden spike in eye pressure can lead to acute and permanent vision loss. This is considered a medical emergency. Symptoms and signs may include:

  • Eye pain

  • Seeing halos around lights

  • Dilated pupils

  • Red eyes

  • Nausea and vomiting

How is glaucoma diagnosed?

A thorough eye exam helps diagnose glaucoma. Eye exams can assess damage to the optic nerve, even during early stages of the condition. If a doctor suspects damage, they will order additional tests. These include a visual field test to examine side vision. The test can identify vision loss a patient might not know about.

“While many people might just think of high eye pressure when they think of glaucoma, about half of all glaucoma cases occur in eyes with pressure in the normal range,” says Dr. Friedman. “That’s why checking the health of the optic nerve is so crucial.”

Glaucoma treatment options

Treatments aim to slow or stop the progression of vision loss. There are three main treatments, all of which help lower pressure in the eye. The right treatment depends on several factors, including:

  1. Glaucoma type

  2. Severity of disease

During each treatment, a doctor regularly checks eye pressure. They also monitor the patient’s side vision and image the optic nerve. If eye pressure, side vision, or health of the optic nerve worsen, they will likely recommend additional treatment to prevent more damage.

Laser treatment for glaucoma

Patients with open angle glaucoma can benefit from laser treatment to lower the eye pressure. This is the most successful initial treatment for glaucoma with open angles. 

The procedure allows the eye to drain more fluid, which lowers eye pressure. According to Dr. Friedman, the procedure has been remarkably safe since its introduction in the 1970s. Beginning treatment with lasers, he adds, can lead to better outcomes than beginning treatment with eye drops. 


Prescribed eye drops can reduce pressure in the eye. While many patients may only need one type of eye drop, some may need a combination of different drops. Doctors may use eye drops as an alternative for laser treatment, especially for patients with open-angle glaucoma.


Dr. Friedman recommends surgery for the most severe glaucoma cases. He also recommends surgery when glaucoma worsens and there are no other ways of effectively lowering eye pressure. 

Glaucoma research

Dr. Friedman feels optimistic about the future of glaucoma care. Researchers are currently trying to figure out why glaucoma damages the optic nerve and studying new treatments in animals. A Mass Eye and Ear scientist has even identified a molecule that could unlock a glaucoma cure.

A few developments he is most excited about are:

  • Virtual reality testing: Headsets used to test vision and side vision could track glaucoma’s progression. The technology could lead to more frequent testing, which may help doctors identify glaucoma at earlier stages. 

  • New drug-delivery methods: Implantable devices in the eye, or contact lenses that deliver drugs to the eye, may offer doctors a new way of delivering eye pressure medications.

  • Gene and stem cell therapy: Gene therapies currently used for retinal conditions could translate into treatments for glaucoma. Stem cells used for creating new tissue may help replace those damaged by the condition. 

Breakthroughs in any one of these developments could lead to care more successful than current options. 

Until then, he urges patients to undergo regular eye exams so they can catch the disease as early as possible. Those who may benefit most from regularly monitoring their eye health include:

  • African Americans

  • Hispanic Americans

  • People with a family history of glaucoma

“Although optic nerve damage from glaucoma cannot be reversed, routine eye evaluations can catch the disease early,” he says. “And those who are under care for glaucoma mostly do well.”

David S. Friedman, MD, PhD, MPH


Glaucoma Specialist