Glaucoma is a disease of the optic nerve – the part of the eye that carries the images we see to the brain. The optic nerve is made up of many nerve fibers, like an electric cable containing numerous wires. When damage to the optic nerve occurs, blind spots develop. These blind spots usually go undetected until the optic nerve is significantly damaged. If the entire nerve is destroyed, blindness results.
Early detection and treatment by your ophthalmologist (Eye M.D.) are the keys to preventing optic nerve damage and blindness from glaucoma.
Glaucoma is the leading cause of blindness in the United States, especially for older people. But loss of sight from glaucoma can often be prevented with treatment.
What causes glaucoma?
Clear liquid called aqueous humor circulates inside the front portion of the eye. To maintain a healthy level of pressure within the eye, a small amount of this fluid is produced constantly while an equal amount flows out of the eye through a microscopic drainage system. (This liquid is not part of the tears on the outer surface of the eye).
Because the eye is a closed structure, if the drainage area for the aqueous humor – called the drainage angle – is blocked, the excess fluid cannot flow out of the eye. Fluid pressure within the eye increases, pushing against the optic nerve and causing damage.
Treatment for glaucoma requires teamwork between you and Dr. Dixon. Dr. Dixon can prescribe treatment for glaucoma, but only you can make sure that you follow your doctor’s instructions and use your eyedrops.
Glaucoma is usually controlled with eyedrops taken daily. These medications lower eye pressure, either by decreasing the amount of aqueous fluid produced within the eye or by improving the flow through the drainage angle.
Never change or stop taking your medications without consulting Dr. Dixon. If you are about to run out of your medication, call Dr. Dixon’s office to ask for a refill.
Glaucoma medications can preserve your vision, but they may also produce side effects. You should notify Dr. Dixon’s Office if you think you may be experiencing any side effects.
All medications can have side effects or can interact with other medications. Therefore, it is important that you make a list of the medications you take regularly and share this list with Dr. Dixon’s Office along with the list of medications that you are allergic to.
Laser Surgery treatments may be recommended for different types of glaucoma.
In open-angle glaucoma, the drain itself is treated. The laser is used to modify the drain (trabeculoplasty) to help control eye pressure.
In closed-angle glaucoma, the laser creates a hole in the iris (iridotomy) to improve the flow of aqueous fluid to the drain.
When medications or laser treatment cannot lower eye pressure enough, surgery is usually recommended. Of the possible procedures, glaucoma filtration surgery, also called trabeculectomy, is the most common.
In performing a trabeculectomy, Dr. Dixon makes a small flap in the white of the eye, called the sclera. A filtration bleb, or reservoir, is created under the conjunctiva, the thin and clear coating that covers the sclera. The aqueous humor inside the eye can then drain through the flap to collect in the bleb, where it absorbed into the lymph and blood vessels around the eye. After the bleb is carefully constructed, the incision is closed with tiny stitches. Some of these stitches may be removed after surgery to increase fluid drainage.
When the risk is high that a trabeculectomy will fail, especially in neovascular glaucoma or glaucoma associated with inflammation in the eye, an aqueous shunt surgery may be recommended. An aqueous shunt is a small tube or valve placed in the eye through a tiny incision. The shunt drains excess fluid into a small reservoir placed on the eye.
When attempts to increase the amount of fluid draining from the eye through the trabecular meshwork fail, another treatment option is to reduce the amount of fluid entering the eye. Cyclophotocoagulation is a procedure that uses a laser beam to treat parts of your eye’s ciliary body. The ciliary body is a band of tissue, located behind where the cornea meets the white part of your eye, that produces the aqueous humor. Treating parts of the ciliary body can reduce the production of aqueous humor, thus lowering eye pressure. Cyclophotocoagulation is generally used to treat advanced or aggressive open-angle glaucoma. It is usually used after other treatments have proven unsuccessful.