Glaucoma is an eye disease where the pressure inside the eye is too high. The result of undiagnosed and untreated glaucoma is damage to the optic nerve, visual loss, and blindness. Part of routine eye care should always include the measurement of intraocular pressure to identify this disease and start treatment. There are two kinds of glaucoma called primary open-angle glaucoma and angle-closure glaucoma (or narrow-angle glaucoma or closed-angle glaucoma). The first has a gradual onset and is why eye doctors should always check your intraocular pressure and look at the optic nerve in the back of the eye for signs of damage. The second can be a medical emergency as the pressure in the eye rises very rapidly. This second condition then requires immediate attention from an experienced ophthalmologist as it can very quickly lead to blindness if untreated.
These are known risk factors for developing glaucoma. Although everyone should have their eye pressure checked routinely and their optic nerve examined, those who fall into these risk categories have greater reason to do so.
Although these factors increase your risk of having glaucoma, glaucoma is seen in people with none of these conditions. We always tell our patients that the worst risk factor is never having your eye pressure checked or your optic nerve examined!
The tests that we do for glaucoma include checking the intraocular pressure and examining the eyes. We look at the cornea in the front of the eye and measure the corneal thickness. Checking the optic nerve for signs of damage is something we do on every exam. We routinely check the drainage angle at the front of the eye and test your peripheral (side) vision. When necessary, we take photos or do computer-assisted measurements of the optic nerve.
In this form of glaucoma, fluid does not drain well at the front of the eye and pressure builds up. There is no pain and people will not notice any visual problems at first. The pressure gradually damages the optic nerve and the person’s vision. Some people have optic nerves that are more sensitive to pressure than others do. Thus, we always look at the optic nerves in both eyes along with checking intraocular pressure to make sure that an overly-sensitive optic nerve is not showing damage even in the high-normal pressure range. It is called “normal tension glaucoma” when the optic pressure is still within the normal range but optic nerve damage happens. When we discover that you have this condition, with high or normal pressure, there are several possible treatments.
There are two different procedures that we can use to treat this kind of glaucoma at our office in Calgary. One uses a laser and the other requires an eye operation.
Trabeculoplasty: We use a laser to improve the drainage angle of the eye, increase the rate of drainage, and reduce the pressure in your eye.
Trabeculectomy: This is a surgical procedure in which we make a little flap in the sclera (the white of the eye) or a pocket in the conjunctiva called a “filtration bleb.” Both of these are hidden under the upper eyelid and not readily visible. The eye fluid (aqueous humor) will drain out of the eye and be absorbed there, thus reducing pressure in the eye.
Glaucoma Drainage Tube: Sometimes we will drain fluid from the eye using a tube instead of simply making a drainage hole. This decision is based on technical factors and is something that we will discuss with you if it becomes necessary.
If the iris of a person’s eye lies too close to the drainage angle at the front of the eye, the iris can block the angle and stop drainage just like blocking the drain of a sink. When this blockage becomes complete the pressure inside the eye goes up very quickly. This acute attack of glaucoma is an eye emergency and needs immediate treatment to avoid blindness.
When to suspect an acute attack of angle-closure glaucoma:
Because the blockage in angle-closure glaucoma may be severe but not complete, this eye disease can also come on more slowly but the end result of undiagnosed and untreated angle-closure glaucoma is still blindness. However, because the progression of visual problems is slower in the chronic form of the condition, there is a better chance of catching it before damage is complete.
When a patient has this type of glaucoma, we may use medications to help reduce the pressure, and for pain, but this problem always requires eye surgery to fix it.
These are all short-term measures.
Peripheral Iridotomy: Using a laser, we make two little holes in the iris of your eye. These drainage holes let fluid drain out and reduce pressure in the eye. We use this procedure to treat both the acute for chronic forms of closed-angle glaucoma.
Surgical Iridectomy: This is a less common treatment in which we operate on your eye to make a small opening in the shape of a triangle in your iris. This allows for better drainage and lower eye pressure.
The vast majority of our glaucoma patients do very well with eye drop therapy and have few or no side effects. When we need to we can change or combine therapies for the best results. When eye drops are not stopping the progression of your glaucoma we will recommend surgery and explain your options. In the case of acute narrow-angle glaucoma attacks, we are available 24 hours a day to attend to this eye emergency.
The most important part of dealing with glaucoma is to know that you are at risk and getting frequent eye exams to measure your pressure and examine the optic nerve. Please contact us if you have any questions or to make an appointment for an eye exam.