Glaucoma is known as the silent thief of vision, and affects nearly three million Americans, but only half of them know they have it. In its early stages, the symptoms of glaucoma are not obvious. Eye exams are the only way to detect glaucoma before it affects your vision. With early detection and treatment, vision loss can be prevented.
At OCB, our fellowship trained glaucoma specialists offer our patients the ongoing comprehensive care required to successfully manage even the most complex cases of glaucoma and protect against further loss of vision.
Glaucoma is a condition characterized by a build-up of fluid in the eye. That extra fluid increases the pressure in the eye which in turn damages the optic nerve and leads to a slow, progressive loss of vision. When glaucoma develops, you usually don’t have any early symptoms. In this way, glaucoma can steal your sight very gradually.
There are several types of glaucoma.
The most common form of glaucoma is called primary open-angle glaucoma. It occurs when the trabecular meshwork of the eye gradually becomes less efficient at draining fluid that circulates in the front part of the eye. Normally this fluid, called aqueous humor, maintains a healthy pressure in the eye. Much like a sink, in the normal eye, the faucet is always on and the drain is always open. In open angle glaucoma, the drain gets clogged and fluid builds up.
As this happens, your eye pressure, called intraocular pressure (IOP), rises. Raised eye pressure may lead to damage of the optic nerve. Damage to the optic nerve can occur at different eye pressures in different patients. There is not one ‘right’ eye pressure that is the same for everyone. Your OCB eye doctor establishes a target eye pressure for you that he or she predicts will protect your optic nerve from further damage.
Typically, open-angle glaucoma has no symptoms in its early stages and your vision remains normal. As the optic nerve becomes more damaged, blank spots begin to appear in your field of vision. You usually won’t notice these blank spots in your day-to-day activities until the optic nerve is significantly damaged and these spots become large.
Low-tension or Normal-tension glaucoma
With this condition, the optic nerve shows signs of damage that are consistent with glaucoma but intraocular pressure is normal or on the low side. The diagnosis is often made after there has been some vision damage. People with low to normal-tension glaucoma are usually treated in the same way as people who have open-angle glaucoma.
This form of glaucoma is a medical emergency and unlike open-angle glaucoma, you are likely to experience symptoms (described below.) Closed angle glaucoma happens when your iris is very close to the eye’s drainage angle. In this case, the iris may block 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. People of Asian descent and those with hyperopia (farsightedness) tend to be more at risk for developing this form of glaucoma.
Call your OCB eye doctor right away should you experience the following symptoms of an acute attack:
Congenital glaucoma is a rare type of glaucoma that develops in infants and young children that is inherited. While far less common than the other types of glaucoma, this condition can result in blindness if not diagnosed and treated early.
Secondary glaucoma is glaucoma that results from another eye condition or disease. For example, someone who has had an eye injury, someone who is on long-term steroid therapy or someone who has a tumor may develop secondary glaucoma.
People who are more risk for developing glaucoma include people who:
With the most common form of glaucoma, open-angle glaucoma, there are no early symptoms. The only way to know if you have glaucoma before it causes irreversible vision loss is to have an eye exam.
On the other hand, a far less common form of glaucoma, closed-angle glaucoma, has severe symptoms and is a medical emergency. Call your OCB eye doctor right away should you experience the following symptoms of an acute attack::
If you are at risk for glaucoma,due to risk factors you should not wait to have an eye exam. Otherwise:
If you have no risk factors or symptoms: You should have a comprehensive eye exam by age 40. This is the time when early signs of disease and changes in vision may begin. Based on the results of the initial screening, your OCB eye doctor will let you know how often to return for follow-up exams.
During your comprehensive eye exam, you OCB eye doctor will evaluate pressure in the eye through tonometry. (See Comprehensive Eye Exam). Normal pressure is 8 to 21 millimeters of mercury (mm Hg) but people with eye pressure in this range may still develop the disease. On the other hand, those who have slightly elevated pressure may not be destined to get glaucoma. How much stress the optic nerve can withstand varies from person to person.
If your OCB eye doctor suspects glaucoma, you can expect to undergo the following tests:
Your OCB eye doctor inspects your optic nerve for signs of damage using an ophthalmoscope, an instrument that magnifies the interior of the eye. Your pupils will be dilated (enlarged) with eye drops to allow your doctor a better view of your optic nerve.
A normal optic nerve is made up of more than one million tiny nerve fibers. As glaucoma damages the optic nerve, it causes the death of some of these nerve fibers. As a result, the appearance of the optic nerve changes. This is referred to as cupping. As the cupping increases, blank spots begin to develop in your field of vision.
If your eye pressure is not in the normal range, or your optic nerve looks unusual, your OCB eye doctor will perform the following glaucoma tests:
Gonioscopy allows your OCB eye doctor to examine the drainage angle of your eye and helps him or her to determine if you have open-angle glaucoma (where the drainage angle is not working efficiently enough), closed-angle glaucoma (where the drainage angle is at least partially blocked), or a dangerously narrow angle (where the iris is so close to the eye’s drain that the iris could block it).
Permimetry (Visual Field Test)
The visual field test will check for blank spots in your vision. Your OCB eye doctor will be able to determine where blank spots appear in your field of vision.
This test is used to measure the thickness of the cornea, the clear window at the front of the eye. A probe called a pachymeter is gently placed on the cornea to obtain this measurement. A very thin cornea may increase your risk of glaucoma.
Most types of glaucoma can be controlled but not cured. The damage caused by glaucoma cannot be reversed, therefore the goal of treatment is to control eye pressure and stop further damage. The most common treatment for glaucoma is medicated eye drops that lower fluid pressure in the eye, preventing any more damage to the optic nerve and further vision loss.
Depending on the severity and responsiveness of your condition, your OCB eye doctor may recommend laser or incisional surgical procedures that will improve drainage of fluid out of the eye, and lower pressure.
If you have glaucoma, preserving your vision requires strong teamwork between you and your OCB eye doctor. Your doctor can prescribe treatment, but it’s important to follow your treatment plan closely. Taking your medications as prescribed is the only way to keep your eye pressure controlled. It is also important to follow through with regular exams as recommended. That way your OCB eye doctor will know whether the fluid pressure in your eye is at a safe range
When you first begin treatment, you may find it challenging to administer your eye drops or keep up with your treatment schedule for a variety of reasons. Be sure to talk with your OCB eye doctor or member of your eye care team about any problems you may have with either keeping on schedule, putting the eye drops in or any side effects you may be experiencing and we will help you find a solution to your unique circumstance. Here are a few tips that help.
To administer your eye drops correctly:
Forgetting to take your eye drops? Try using alert features on your smart phone or e-calendar or put your eye drops near your toothbrush or next to your vitamins you take daily. You could also use a calendar and check it off each day after you take the medication.