What is Glaucoma ?
Glaucoma is a disease that damages your eye’s optic nerve. It usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve.
Glaucoma is a leading cause of blindness for people over 60 years old. But blindness from glaucoma can often be prevented with early treatment.
Types of glaucoma
There are two major types of glaucoma.
Primary open-angle glaucoma
This is the most common type of glaucoma. It happens gradually, where the eye does not drain fluid as well as it should (like a clogged drain). As a result, eye pressure builds and starts to damage the optic nerve. This type of glaucoma is painless and causes no vision changes at first.
Some people can have optic nerves that are sensitive to normal eye pressure. This means their risk of getting glaucoma is higher than normal. Regular eye exams are important to find early signs of damage to their optic nerve.
This type happens when someone’s iris is very close to the drainage angle in their eye. The iris can end up blocking the drainage angle. You can think of it like a piece of paper sliding over a sink drain. When the drainage angle gets completely blocked, eye pressure rises very quickly. This is called an acute attack. It is a true eye emergency, and you should call your ophthalmologist right away or you might go blind.
Here are the signs of an acute angle-closure glaucoma attack:
- Your vision is suddenly blurry
- You have severe eye pain
- You have a headache
- You feel sick to your stomach (nausea)
- You throw up (vomit)
- You see rainbow-colored rings or halos around lights
Many people with angle-closure glaucoma develop it slowly. This is called chronic angle-closure glaucoma. There are no symptoms at first, so they don’t know they have it until the damage is severe or they have an attack.
Angle-closure glaucoma can cause blindness if not treated right away.
Laser surgery has become increasingly popular as an intermediate step between drugs and traditional surgery though the long-term success rates are variable. The most common type performed for open-angle glaucoma is called trabeculoplasty. This procedure takes between 10 and 15 minutes, is painless, and can be performed in either a doctor’s office or an outpatient facility. The laser beam (a high energy light beam) is focused upon the eye’s drain. Contrary to what many people think, the laser does not burn a hole through the eye. Instead, the eye’s drainage system is changed in very subtle ways so that aqueous fluid is able to pass more easily out of the drain, thus lowering IOP.
Argon Laser Trabeculoplasty (ALT) — for open-angle glaucoma
The laser treats the trabecular meshwork of the eye, increasing the drainage outflow, thereby lowering the IOP. In many cases, medication will still be needed. Usually, half the trabecular meshwork is treated first. If necessary, the other half can be treated as a separate procedure. This method decreases the risk of increased pressure following surgery. Argon laser trabeculoplasty has successfully lowered eye pressure in up to 75 percent of patients treated. This type of laser can be performed only two to three times in each eye over a lifetime.
Selective Laser Trabeculoplasty (SLT) — for open-angle glaucoma
SLT is a newer laser that uses very low levels of energy. It is termed “selective” since it leaves portions of the trabecular meshwork intact. For this reason, it is believed that SLT, unlike other types of laser surgery, may be safely repeated. Some authors have reported that a second repeat application of SLT or SLT after prior ALT is effective at lowering IOP.
Laser Peripheral Iridotomy (LPI) — for angle-closure glaucoma
This procedure is used to make an opening through the iris, allowing aqueous fluid to flow from behind the iris directly to the anterior chamber of the eye. This allows the fluid to bypass its normal route. LPI is the preferred method for managing a wide variety of angle-closure glaucomas that have some degree of pupillary blockage. This laser is most often used to treat an anatomically narrow angle and prevent angle-closure glaucoma attacks.
Two laser procedures for open-angle glaucoma involve reducing the amount of aqueous humor in the eye by destroying part of the ciliary body, which produces the fluid. These treatments are usually reserved for use in eyes that either have elevated IOP after having failed other more traditional treatments, including filtering surgery, or those in which filtering surgery is not possible or advisable due to the shape or other features of the eye. Transscleral cyclophotocoagulation uses a laser to direct energy through the outer sclera of the eye to reach and destroy portions of the ciliary processes, without causing damage to the overlying tissues.