The only sure way to diagnose glaucoma is with a complete eye exam. A glaucoma screening that only checks eye pressure is not enough to find glaucoma.

During a glaucoma exam, your ophthalmologist will:

• Measure your eye pressure
• Inspect your eye’s drainage angle
• Examine your optic nerve for damage
• Test your peripheral (side) vision
• Take a picture or computer measurement of your optic nerve
• Measure the thickness of your cornea

Open-angle glaucoma
With open-angle glaucoma, there are no warning signs or obvious symptoms in the early stages. As the disease progresses, blind spots develop in your peripheral (side) vision.

Most people with open-angle glaucoma do not notice any change in their vision until the damage is quite severe. This is why glaucoma is called the “silent thief of sight.” Having regular eye exams can help your ophthalmologist find this disease before you lose vision. Your ophthalmologist can tell you how often you should be examined.

Angle-closure glaucoma
People at risk for angle-closure glaucoma usually show no symptoms before an attack. Some early symptoms of an attack may include blurred vision, halos, mild headaches or eye pain. People with these symptoms should be checked by their ophthalmologist as soon as possible. An attack of angle-closure glaucoma includes the following:

• Severe pain in the eye or forehead
• Redness of the eye
• Decreased vision or blurred vision
• Seeing rainbows or halos
• Headache
• Nausea
• Vomiting
• Normal tension glaucoma

People with “normal tension glaucoma” have eye pressure that is within normal ranges, but show signs of glaucoma, such as blind spots in their field of vision and optic nerve damage.

Some people have no signs of damage but have higher than normal eye pressure (called ocular hypertension). These patients are considered “glaucoma suspects” and have a higher risk of eventually developing glaucoma. Some people are considered glaucoma suspects even if their eye pressure is normal.

For instance, their ophthalmologist may notice something different about their optic nerve. Anyone who is considered a glaucoma suspect should be carefully monitored by their ophthalmologist.

An ophthalmologist can check for any changes over time and begin treatment if needed.

Your eye constantly makes aqueous humor. As new aqueous flows into your eye, the same amount should drain out. The fluid drains out through an area called the drainage angle.

This process keeps pressure in the eye (called intraocular pressure or IOP) stable. But if the drainage angle is not working properly, fluid builds up. Pressure inside the eye rises, damaging the optic nerve.

The optic nerve is made of more than a million tiny nerve fibers. It is like an electric cable made up of many small wires. As these nerve fibers die, you will develop blind spots in your vision. You may not notice these blind spots until most of your optic nerve fibers have died. If all of the fibers die, you will become blind.

Trabeculoplasty. This surgery is for people who have open-angle glaucoma. The eye surgeon uses a laser to make the drainage angle work better. That way fluid flows out properly and eye pressure is reduced.

Iridotomy. This is for people who have angle-closure glaucoma. The ophthalmologist uses a laser to create a tiny hole in the iris. This hole helps fluid flow to the drainage angle

Laser Surgery
Doctors often recommend laser surgery before incisional surgery, unless the eye pressure is very high or the optic nerve is badly damaged. During laser surgery, a focused beam of light is used to treat the eye’s trabecular meshwork (the eye’s drainage system). This helps increase the flow of fluid out of the eye.

Incisional Surgery
In contrast, incisional surgery (also called filtering surgery) involves creating a drainage hole with the use of a small surgical tool. This new opening allows the intraocular fluid to bypass the clogged drainage canals and flow out of this new, artificial drainage canal.

When laser surgery does not successfully lower eye pressure, or the pressure begins to rise again, the doctor may recommend incisional surgery. Occasionally, glaucoma surgery may have to be repeated especially if excessive scarring cannot be prevented or after long periods of time.