Glaucoma Evaluations
Glaucoma is a leading cause of blindness in people over forty – yet almost all blindness due to this eye condition is preventable. Glaucoma is not an infection, nor is it contagious. It is a condition in which pressure created by the fluid in one or both eyes builds to an abnormally high level. Ultimately, this pressure causes damage to the delicate visual structures of the eye and when left untreated can cause blindness.
Glaucoma develops when the aqueous humor (normal fluid contained in the front part of the eye) does not drain properly, causing pressure in the eye to rise. Nerve fibers and blood vessels in the optic nerve are compressed and can be damaged or destroyed. As a result, visual messages are not adequately transmitted to the brain, causing impaired vision and, ultimately, blindness.
The most common type of glaucoma, chronic glaucoma, is virtually painless. In fact, most people with chronic glaucoma are not even aware that they are being robbed of their sight since the visual loss is so gradual. In most cases, there are no warning signs before vision is lost. “Tunnel vision” – seeing only a small area in the center of vision — develops and gradually narrows. By the time vision problems develop, irreversible damage may already have occurred.
A less common form of glaucoma, acute glaucoma, is marked by sudden, severe pain in and around the eye. Vision is sharply decreased, and, in many cases, nausea and vomiting is experienced. Emergency treatment (usually laser or traditional surgery) is required to alleviate the pressure and prevent further damage. In addition to these two forms of the condition, glaucoma can also occur as a result of inflammation of, or injury to the eye. In rare instances, infants are born with the condition.
Glaucoma can silently steal your vision without warning. Fortunately, there is something you can do to protect your eyesight. Especially if you are over forty, it is critical to have regular eye examinations. Because chronic glaucoma seldom causes symptoms, early detection and treatment are the only ways to prevent permanent loss of vision.
During your eye examination, inform your doctor if other members of your family have glaucoma. This is extremely important because the condition tends to be hereditary. Also inform your doctor of any medications you are currently taking. After completing the routine exam, specific tests will be conducted to confirm the presence of glaucoma. These tests include:
TONOMETRY
Testing your eye pressure is an important part of a glaucoma evaluation. A high pressure reading is often the first sign that you have glaucoma. During this test, your eye is numbed with eyedrops. Your doctor uses an instrument called a tonometer to measure eye pressure. The instrument measures how your cornea resists pressure. Another method used can involve a puff of air. Normal eye pressure generally ranges between 10 and 21 mm Hg.
GONIOSCOPY
Gonioscopy allows your doctor to get a clear look at the drainage angle to determine the type of glaucoma you may have. Your doctor is not able to see your eye’s drainage angle by looking at the front of your eye. However, by using a mirrored lens, he or she can examine the drainage angle 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).
OPHTHALMOSCOPY
Your 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 (widened) with eyedrops 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. At Family Eye Care Optometry, we also use a special retinal camera to closely monitor any changes in your optic nerves.
VISUAL FIELD TEST
The peripheral (side) vision of each eye is tested with visual field testing, or perimetry. For this test, you sit at a bowl-shaped instrument called a perimeter. While you stare at the center of the bowl, lights flash. Each time you see a flash, you press a button. A computer records your response to each flash. This test shows if you have any areas of vision loss. Loss of peripheral vision is often an early sign of glaucoma.
PACHYMETRY
Because the thickness of the cornea can affect eye pressure readings, pachymetry is used to measure corneal thickness. A probe called a pachymeter is gently placed on the cornea to measure its thickness.
Each of these evaluation tools is an important way to monitor your vision to help ensure that glaucoma does not rob you of your sight. Some of these tests will not be necessary for everyone. Your doctor will discuss which tests are best for you. Some tests may need to be repeated on a regular basis to monitor any changes in your vision caused by glaucoma.
TREATMENT
Glaucoma is treated by reducing and controlling the pressure inside the eye. This may be done through the use of eye medications (drops), the use of lasers, or in some cases, using more advanced surgery to improve the eye's drainage system. Regardless of the method of treatment, it is very important for patients to have their pressures monitored regularly.
Glaucoma develops when the aqueous humor (normal fluid contained in the front part of the eye) does not drain properly, causing pressure in the eye to rise. Nerve fibers and blood vessels in the optic nerve are compressed and can be damaged or destroyed. As a result, visual messages are not adequately transmitted to the brain, causing impaired vision and, ultimately, blindness.
The most common type of glaucoma, chronic glaucoma, is virtually painless. In fact, most people with chronic glaucoma are not even aware that they are being robbed of their sight since the visual loss is so gradual. In most cases, there are no warning signs before vision is lost. “Tunnel vision” – seeing only a small area in the center of vision — develops and gradually narrows. By the time vision problems develop, irreversible damage may already have occurred.
A less common form of glaucoma, acute glaucoma, is marked by sudden, severe pain in and around the eye. Vision is sharply decreased, and, in many cases, nausea and vomiting is experienced. Emergency treatment (usually laser or traditional surgery) is required to alleviate the pressure and prevent further damage. In addition to these two forms of the condition, glaucoma can also occur as a result of inflammation of, or injury to the eye. In rare instances, infants are born with the condition.
Glaucoma can silently steal your vision without warning. Fortunately, there is something you can do to protect your eyesight. Especially if you are over forty, it is critical to have regular eye examinations. Because chronic glaucoma seldom causes symptoms, early detection and treatment are the only ways to prevent permanent loss of vision.
During your eye examination, inform your doctor if other members of your family have glaucoma. This is extremely important because the condition tends to be hereditary. Also inform your doctor of any medications you are currently taking. After completing the routine exam, specific tests will be conducted to confirm the presence of glaucoma. These tests include:
TONOMETRY
Testing your eye pressure is an important part of a glaucoma evaluation. A high pressure reading is often the first sign that you have glaucoma. During this test, your eye is numbed with eyedrops. Your doctor uses an instrument called a tonometer to measure eye pressure. The instrument measures how your cornea resists pressure. Another method used can involve a puff of air. Normal eye pressure generally ranges between 10 and 21 mm Hg.
GONIOSCOPY
Gonioscopy allows your doctor to get a clear look at the drainage angle to determine the type of glaucoma you may have. Your doctor is not able to see your eye’s drainage angle by looking at the front of your eye. However, by using a mirrored lens, he or she can examine the drainage angle 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).
OPHTHALMOSCOPY
Your 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 (widened) with eyedrops 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. At Family Eye Care Optometry, we also use a special retinal camera to closely monitor any changes in your optic nerves.
VISUAL FIELD TEST
The peripheral (side) vision of each eye is tested with visual field testing, or perimetry. For this test, you sit at a bowl-shaped instrument called a perimeter. While you stare at the center of the bowl, lights flash. Each time you see a flash, you press a button. A computer records your response to each flash. This test shows if you have any areas of vision loss. Loss of peripheral vision is often an early sign of glaucoma.
PACHYMETRY
Because the thickness of the cornea can affect eye pressure readings, pachymetry is used to measure corneal thickness. A probe called a pachymeter is gently placed on the cornea to measure its thickness.
Each of these evaluation tools is an important way to monitor your vision to help ensure that glaucoma does not rob you of your sight. Some of these tests will not be necessary for everyone. Your doctor will discuss which tests are best for you. Some tests may need to be repeated on a regular basis to monitor any changes in your vision caused by glaucoma.
TREATMENT
Glaucoma is treated by reducing and controlling the pressure inside the eye. This may be done through the use of eye medications (drops), the use of lasers, or in some cases, using more advanced surgery to improve the eye's drainage system. Regardless of the method of treatment, it is very important for patients to have their pressures monitored regularly.
