Glaucoma

Glaucoma and Its Treatments

Glaucoma is often called “the silent thief” because Glaucoma can steal your vision, without any warning or symptoms. Of the estimated three million Americans who have glaucoma, only about half are aware they have it. Glaucoma does not cause pain and the damage to your eyesight progresses slowly.

This is one of many reasons why annual eye exams are vital. Glaucoma should be evaluated by your eye doctor, during an eye examination when testing reveals elevated intraocular pressure (IOP) or cupping of the optic nerve.

What Is Cupping of the Optic Nerve?

The optic disc has a center portion called the “cup” which is normally quite small compared to the entire optic disc. In people with glaucoma damage, because of increased pressure in the eye and/or loss of blood flow to the optic nerve, these nerve fibers begin to die.

This causes the cup to become larger in comparison to the optic disc, since the support structure is not there. Optic nerve cupping progresses as the cup becomes larger in comparison to the optic disc.

What Causes Glaucoma?

Glaucoma damages the eye’s optic nerve, which is made up of many nerve fibers, like an electric cable is made up of many wires. The optic nerve connects your retina, where images are projected, to your brain, where the images are interpreted. Elevated IOP damages the fibers in the optic nerve, and if left untreated, this causes blindness.

The precise cause of glaucoma is unknown. A family history of glaucoma raises your risk of developing the disease. Other risk factors include age, African or Hispanic ancestry, past eye injury, and conditions that affect blood flow (migraines, diabetes, low blood pressure).

Early detection of glaucoma and treatment with eye drops, surgery, or both, can slow the progression of glaucoma and preserve the vision you have. There are five simple steps that are essential to managing glaucoma:

1. After the age of 40, have yearly eye examinations that include the measurement of IOP.
2. If you are found to have elevated IOP, follow the doctor’s treatment plan to control it.
3. Continue to have your IOP measured at intervals recommended by your doctor.
4. If surgery is indicated, don’t delay it, and follow the surgeon’s instructions.
5. Continue to follow your doctor’s recommendations for monitoring and treating glaucoma.

Surgical Treatment

While most of the time glaucoma is managed with eye drops that lower IOP, surgery may be recommended for other patients. Glaucoma surgery improves the flow of fluid out of the eye, lowering IOP and can lessen the need for prescription eye drops.

In the eye, a clear fluid circulates inside the front portion. To maintain a constant healthy eye pressure, the eye continually produces a small amount of this fluid, (called aqueous humor) while an equal amount of this fluid flows out of your eye. If you have glaucoma, the aqueous humor does not flow out of the eye properly, elevating the IOP.

There are a number of surgical options that your surgeon may consider:

• SLT Laser: In Selective Laser Trabeculoplasty(SLT), the surgeon uses a low-level energy laser to target specific cells in the mesh-like channels where fluid flows out of the eye. Using very short applications of light, the surgeon enlarges the openings so fluid will flow more readily. The treatment has been shown to lower IOP. The advantage of this laser procedure is that if the pressure elevates the procedure can be repeated.
• YAG PI Laser: This type of laser is used to perform a peripheral iridotomy, which is a treatment for a specific type of glaucoma called narrow angle glaucoma. The surgeon uses the YAG laser to create a small hole at the edge of the iris (the colored part of your eye). This improves the flow of fluid (aqueous humor) through the eye’s internal drainage system. Sometimes this lowers IOP, but the primary goal of this procedure is to reduce the risk of narrow-angle glaucoma.
• Trabeculectomy: In Trabeculectomy, a small flap is made in the outer white coating of your eye. A reservoir, called a bleb, is created. The bleb looks like a bump or blister on the white part of the eye above the iris, but the upper eyelid usually covers it. The fluid (aqueous humor) can now drain through the flap made in the sclera and collect in the bleb, where the fluid will be absorbed into blood vessels around the eye. IOP is effectively controlled in three out of four people who have trabeculectomy. If the new drainage channel closes or too much fluid begins to drain from the eye, additional surgery may be needed.
• Tube Shunt Procedures: If trabeculectomy cannot be performed, tube shunt procedures usually are effective in lowering IOP. A shunt is a small plastic tube or valve connected on one end to a reservoir. The shunt is implanted in the eye through a tiny incision. The shunt redirects fluid to an area beneath your eye. The fluid is then absorbed into the blood vessels. When healed, the reservoir is not easily seen unless you look downward and lift your eyelid.
• iStent: The iStent Trabecular Micro-bypass, a revolution in glaucoma surgery, is implanted at the time of cataract surgery. The iStent is clinically proven to reduce eye pressure in adult patients with both cataracts and mild-to-moderate open-angle glaucoma. This device is the smallest medical implant known to be implanted in the human body. In U.S. trials, iStent was shown to be effective in decreasing IOP, with an excellent safety profile, few complications, fast recovery time, and has been implanted in over 100,000 eyes around the world.