What is glaucoma?
Glaucoma is an eye disease that results from increased pressure within the eye caused by fluid backup. Over time, this elevated pressure will cause damage to the optic nerve and lead to blindness.
Risk Factors for Glaucoma:
- Family history of glaucoma
- African American
- Past ocular injury
- Increased eye pressure
- Possibly corneal thickness (i.e., thin corneas may underestimate true eye pressure)
It is important to understand that increased eye pressure, although frequently associated with Glaucoma, is not necessary for the diagnosis since the optic nerve can continue to lose function in the face of “normal pressure” in many patients.
Most common type of glaucoma
There are several types of glaucoma. The two main types are open-angle and angle-closure. These are marked by an increase of intraocular pressure (IOP), or pressure inside the eye.
Primary open-angle glaucoma is the most common type of glaucoma.It develops over time, when your eye does not drain fluid as well as it should (think of a clogged drain). As a result, your eye pressure increases and starts to damage the optic nerve. Because primary open-angle glaucoma is a chronic condition, it has to be managed for life. At least 90% of all glaucoma cases:
- Is caused by the slow clogging of the drainage canals, resulting in increased eye pressure
- Has a wide and open angle between the iris and cornea
- Develops slowly and is a lifelong condition
- Has symptoms and damage that are not noticed.
Angle-closure glaucoma, a less common form of glaucoma:
- Is caused by blocked drainage canals, resulting in a sudden rise in intraocular pressure
- Has a closed or narrow angle between the iris and cornea
- Develops very quickly
- Has symptoms and damage that are usually very noticeable
- Demands immediate medical attention.
It is also called acute glaucoma or narrow-angle glaucoma. Unlike open-angle glaucoma, angle-closure glaucoma is a result of the angle between the iris and cornea closing.
Normal-Tension Glaucoma (NTG)
Also called low-tension or normal-pressure glaucoma. In normal-tension glaucoma the optic nerve is damaged even though the eye pressure is not very high. We still don’t know why some people’s optic nerves are damaged even though they have almost normal pressure levels.
Other Types of Glaucoma
Variants of open-angle and angle-closure glaucoma include:
- Secondary Glaucoma
- Pigmentary Glaucoma
- Pseudoexfoliative Glaucoma
- Traumatic Glaucoma
- Neovascular Glaucoma
- Irido Corneal Endothelial Syndrome (ICE)
How is Glaucoma Detected?
Regular eye examinations are the best way to detect glaucoma. An eye screening that only checks eye pressure is not sufficient. A thorough glaucoma evaluation includes:
- Tonometry: Measures intraocular pressure
- Gonioscopy: Allows visualization of the drainage angle of the eye
- Optic nerve evaluation: To evaluate if there is optic nerve damage. This can be done by direct visualization with proper equipment. An additional method is with a new technically advanced optic nerve analyzer using scanning laser tomography. This highly advanced system is now available at the California Eye Medical Center.
- Visual Field Testing: This tests the function of the optic nerve by mapping out the peripheral vision
- Stereo optic disc photos
Symptoms can be hard to notice:
At first, primary open-angle glaucoma has no symptoms. There’s no pain and your vision stays normal. However, if left untreated, glaucoma will cause you to slowly lose your peripheral (side) vision. Imagine looking through a tunnel, where the objects on either side are getting lost. That’s what vision with glaucoma is like. If the condition remains untreated, vision loss will continue and that tunnel will get smaller and smaller. Once your vision is lost, you can’t get it back. That’s why early diagnosis—and continued management—are so important.
Early detection is the key to saving your sight. A simple test during regular eye exams can catch glaucoma in its earliest stages. Glaucoma can be treated with eye drops, pills, laser surgery, traditional surgery or a combination of these methods. The goal of any treatment is to prevent loss of vision, as vision loss from glaucoma is irreversible. Medications and eye drops are the usual first course of action in treating glaucoma. Following your doctors’ directions is crucial in preventing damage and loss of sight.
Medications: Glaucoma is usually controlled with eye drops taken on a daily basis. These medications decrease eye pressure.
- Laser surgery: Laser surgery treatments may be recommended for different types of glaucoma. In chronic open angle glaucoma, a procedure called a trabeculoplasty is performed to help facilitate fluid to exit through the natural drain of the eye and therefore, decrease intraocular pressure. This is done in an office setting, and usually takes less than five minutes. Dr. Sacks performs Selective Laser Trabeculoplasty (SLT) in his office to lower intraocular pressure. SLT is a safe and effective in-office procedure. It usually requires only one treatment and may reduce or eliminate the need for topical glaucoma drops. In many instances SLT can be used as a primary treatment, instead of drops. Insurance covers the procedure in most cases. Ask Dr. Sacks if SLT is right for your glaucomatous eye. In angle closure glaucoma, or narrow angles, a laser peripheral iridotomy is performed to create a small opening in the iris. This too takes less than five minutes in most cases and can be done in the office setting. Both procedures are painless.
- Surgery in the operating room: Microsurgical instruments are used to create a new drainage channel for the fluid in the eye. This is typically done as an outpatient at a surgery center or hospital. This procedure, called a trabeculectomy, or another procedure, called a “shunt” procedure is usually done if medications or laser cannot control the pressure.