Glaucoma & Cornea
Glaucoma, the leading cause of blindness and visual impairment in the United States, is an eye disease that can lead to a permanent loss of vision. This disease has been labeled the “Sneak Thief of Sight” because in its most typical form, there are no symptoms -- no pain, no swelling, no redness. Patients with glaucoma may not notice symptoms until vision has been permanently lost.
Glaucoma is a disease process that progressively damages the optic nerve, the structure that transmits the visual stimulus from the eye to the brain. Most patients with glaucoma have elevated intraocular pressure.. Every eye has fluid, called aqueous humor, which is constantly being produced as well as constantly being drained. In a glaucomatous eye, this fluid does not drain properly resulting in an increase in the pressure inside the eye. This increased pressure destroys vision gradually, usually starting with the peripheral (side) vision. If left untreated, it will lead to eventual blindness by destroying the optic nerve. With early diagnosis and treatment, useful vision may be preserved. The only known treatment for glaucoma is to lower the intraocular pressure. Typically we attempt to lower the intraocular pressure with eye drop medications. This works in most cases but sometimes we have to perform a surgery on the eye to lower the pressure.
There are four types of glaucoma:
- Chronic – This is the most common type of glaucoma and occurs slowly over time. There is no pain, redness, swelling or other symptoms.
- Acute – This happens suddenly and is very painful. Victims of an acute glaucoma attack may complain of serious headache and vomiting. Medical intervention is needed immediately to bring the pressure under control to prevent further vision loss.
- Congenital – Present at birth, congenital glaucoma is a rather rare condition.
- Secondary – Occurring as a result of systemic disease such as diabetes, from medications such as steroids, or from an eye injury.
Glaucoma occurs when the clear fluid that keeps the eye formed and nourished is unable to drain from the eye through the drainage system (Trabecular meshwork). Because the fluid is unable to drain, pressure builds in the eye and over time may cause damage to the optic nerve and lead to vision loss. Medication, laser surgery, or other glaucoma surgeries may be used to lower and control the intraocular pressure.
When is surgery necessary?
When medication and laser treatments cannot control the eye pressure adequately, surgery is usually recommended. Glaucoma filtering surgery (Trabeculectomy) is the most common.
What is a Trabeculectomy and how is it performed?
Your doctor will make a small flap in the sclera (white part of the eye). A filtration bleb, or reservoir is created under the conjunctiva (thin, clear coating over the sclera) . The bleb looks like a blister or bump on the white part of the eye but is usually hidden by the upper lid. The fluid inside the eye can then drain through the flap, collect in the bleb where it is reabsorbed into the body.
After the bleb is constructed, the incision is closed with stitches. These stitches can be removed to increase fluid drainage. Then your physician will apply medications to reduce the risk of scarring.
Some patients will need additional procedures performed if the primary bleb fails due to scarring. The secondary procedure requires the placement of a valve under the conjunctiva with a small tube that is positioned inside the eye to facilitate fluid drainage. This is only performed for those patients with a primary bleb failure, a risk of primary bleb failure, or specific types of glaucoma. Your physician will discuss with you which procedure would be best for your specific diagnosis.
The day of surgery
A trabeculectomy is usually done on an outpatient basis with local anesthesia. You will be given a sedative to help you relax. The procedure usually takes about one hour.
Follow up care is as important to the success of the surgery as the operation itself. During your follow-up examinations your doctor will examine the bleb, the intraocular pressure, the back of the eye and the overall appearance of the eye. You should avoid bending, lifting, or straining until your eye pressure stabilizes.
Pain after surgery is unusual; your eye may be tender and sensitive. A non aspirin pain reliever is usually sufficient to treat any discomfort. However, sudden, severe, or deep seated pain should be reported to your ophthalmologist immediately.
Your vision will fluctuate after surgery; generally your vision will be blurry for several weeks. Surgery cannot restore vision already lost to glaucoma.