Glaucoma is a disease of the optic nerve. Glaucoma is a leading cause of blindness in the United States, especially for older people. But loss of sight from glaucoma can often be prevented with early treatment.
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.
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
- 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.
New Findings in Glaucoma:
A recent study, called the Ocular Hypertension Treatment Study, revealed that measuring corneal thickness is an important variable in helping the doctor to decide whether patients with ocular hypertension need to be treated or not. Dr. Sacks performs this test with Ultrasonic Pachymetry.
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.
Open-angle glaucoma, the most common form of glaucoma, accounting for 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.
“Open-angle” means that the angle where the iris meets the cornea is as wide and open as it should be. Open-angle glaucoma is also called primary or chronic glaucoma. It is the most common type of glaucoma, affecting about three million Americans
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)