Glaucoma

What It Is and Its Causes

What Is Glaucoma?

Glaucoma is a disease that damages the eye’s optic nerve. Its main risk factor is high eye pressures. Glaucoma is a leading cause of blindness for people over 60 years of age. Blindness from glaucoma can often be prevented with early treatment.

What Causes Glaucoma?

Your eye constantly makes aqueous humor, a fluid that nourishes the lens and cornea. The lens and cornea have no blood vessels in them allowing them to be clear so we can see through them. The lens and cornea rely on this aqueous fluid to stay healthy. As new aqueous fluid flows into the eye, the same amount should drain out. The fluid drains out through an area called the drainage angle. If the drainage angle is not working properly, fluid builds up. This causes the pressure in the entire eye to go up and this damages the optic nerve.

The optic nerve is made up of approximately 1.2 million nerve fibers. As these nerve fibers are damaged, they die off and you develop blind spots in your vision. Most people do not notice these blind spots until most of the optic nerve fibers have died. If all of the fibers die, you will become blind.

Types of Glaucoma

Primary Open-angle Glaucoma

Primary open-angle glaucoma is the most common type of glaucoma. It happens very gradually as the fluid in the eye does not drain as it should. As the pressure builds, if left untreated, it damages the optic nerve. This type of glaucoma is painless and the patient does not notice vision changes at first. This type is best picked up early by having regular eye exams.

Normal Tension Glaucoma

Normal tension glaucoma patients have eye pressures that are in the normal range. In spite of the seemingly normal pressures they develop damage to their nerves and blind spots in their field of vision.

Angle-closure Glaucoma

Angle-closure glaucoma (narrow-angle glaucoma) is a type of glaucoma that causes a relatively rapid, severe increase in eye pressure. This occurs in people who have narrow drains and the iris can block the drain. Unlike the other types of glaucoma, this type can cause symptoms of: blurred vision, eye pain, headache, halos and nausea/vomiting.

It is a true emergency, and you should be seen as soon as possible if you have these symptoms as it can cause blindness if not treated right away.

Diagnosis and Treatment

How Is Glaucoma Diagnosed?

The only sure way to diagnose glaucoma is with a complete eye exam. A screening that only checks eye pressures is not enough to find glaucoma, especially the normal-tension type.

During your glaucoma exam your ophthalmologist will:

  • Measure your eye pressure
  • Inspect the drainage angle of your eye
  • 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

How Is Glaucoma Treated?

Glaucoma damage is permanent—it cannot be reversed. Eye drops and surgery help stop further damage. If you are diagnosed with this disease, you can expect to be seen about every 4-6 months. You have many options for treatment.

Medications
Glaucoma is most commonly controlled with eye-drop medications. These prescription drops must be used every day to control the pressures and prevent vision loss. There are many different medications (drops) to help control eye pressures.

Laser Surgery
There are two main types of laser surgery to treat glaucoma. They work by helping the aqueous fluid to drain more efficiently from the eye. These may be done in the office.

  • Trabeculoplasty is a laser for open-angle glaucoma. It may be used instead of or in addition to medications. The laser is used to make the drainage angle work better, therefore lowering the eye pressure. It is successful 75% of the time and may last for an average of 2-3 years. By 5 years half of patients have increased eye pressures and the laser may need to be repeated or another treatment used.
  • Iridotomy is used for angle-closure glaucoma. The laser is used to make a tiny hole in the iris to help the fluid drain to the angle.

Durysta Implant is a small implant that may be injected into the front of the eye to slowly release bimatoprost, a glaucoma medication that lowers eye pressures. This may last as long as 6-24 months before it needs repeating.

Operating Room Surgery
Dr. Gleason and Dr. Janky offer glaucoma surgery done in an operating room. Some of these surgeries can be done at the same time as your cataract surgery.

  • Cataract surgery itself can help patients with the narrow angle type of glaucoma. Removing the cataract (cloudy lens) creates more space for the fluid to leave the eye.
  • Goniotomies or surgically opening the drain allows better flow of the aqueous.
  • Tiny titanium stents (iStent infinite) can be placed in the drain to allow better out flow of the aqueous. Most insurance companies cover these procedures. Goniotomies and stents may be done at the same time as cataract surgery or separate from cataract surgery.
  • Sustained release medications (iDose TR) may be placed in the eye to slowly release travoprost (a glaucoma medication) to help control elevated eye pressures.

For patients with more resistant disease, there are other surgeries: trabeculectomy, tube shunt surgery or cyclophotocoagulation.