E. Randy Craven, M.D. |
John Samples, M.D. |
Glaucoma is a disease that affects the optic nerve, the part of the eye which receives images collected by the retina and sends them to the brain. Every eye maintains a certain amount of internal pressure, called intraocular pressure. When this pressure rises to abnormal levels however, it can put extra stress on the optic nerve, causing significant damage. Optic nerve damage results in loss of vision, and ultimately blindness.
The front of the eye is constantly producing a fluid called aqueous humor. A healthy eye will continually produce small amounts of aqueous humor to ensure consistent pressure within the eye. When normal drainage becomes slowed or blocked, pressure increases, and may lead to glaucoma. There are several different types of glaucoma the two most common types being chronic open-angle glaucoma and closed-angle glaucoma.
CLICK HERE FOR A VIDEO ON GLAUCOMA
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Glaucoma Eye
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| Normal Vision Vision with Glaucoma Damage |
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Open-Angle Glaucoma is the most common form of the disease and occurs when the fluid that normally circulates in the front portion of the eye is blocked from flowing back out of the eye through a tiny drainage system called the trabecular meshwork. When the fluid is blocked from leaving the eye, it will cause the pressure inside your eye to rise. This increase in eye pressure can damage the optic nerve, which causes vision loss. The vision loss as shown in the photograph is frequently a loss of the peripheral vision. This is why testing the visual field is important for glaucoma management and diagnosis. Most patients do not notice anything different with their eyes until they experience impairments with their vision.
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Risk factors for chronic open-angle glaucoma include:
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Advanced age.
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Family history of the disease.
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Higher-than-normal intraocular pressure.
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Certain ethnic races, particularly those of African descent.
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Certain diseases or conditions, especially diabetes, farsightedness or nearsightedness, or previous eye trauma or surgery.
Angle-Closure Glaucoma is also known as acute angle closure or narrow angle glaucoma. With this form of glaucoma, there is a sudden increase in the eye pressure. The iris (colored part of the eye) will sometimes push forward against the drainage canal, blocking the drain. When the drain becomes blocked, it causes the sudden increase in eye pressure. This increase in pressure can cause optic nerve damage. People with angle-closure glaucoma can experience what is known as an angle-closure attack. The attack is caused by the sudden increase in eye pressure. Symptoms of an angle-closure attack include nausea, vomiting, and eye pain. Attacks are considered an emergency. Optic nerve damage and vision loss can occur within hours of an attack.
If you are diagnosed with angle-closure glaucoma, please talk to your doctor about what you can do to help prevent angle-closure attacks.
Chronic-angle closure glaucoma is a slow form of the same problem. It develops slowly and usually does not have the sudden increase in pressure. This may require surgery to treat.
CLICK HERE FOR A VIDEO ON ANGLE-CLOSURE/NARROW ANGLE GLAUCOMA
Symptoms of angle-closure glaucoma include:
High risk factors for closed-angle glaucoma include:
Normotensive or Low-Pressure Glaucoma is different than high-pressure glaucoma. It is most often seen in women in their 40's, but it can also be seen in either sex or other ages. It probably represents 30% of the glaucoma patients. Many patients are missed with the diagnosis because their eye pressure is "normal." The criterion for this diagnosis is usually a pressure of less than 21mmHG. People of Chinese, English and Japanese descent may have a higher prevalence of this problem, and a gene has been identified. The OPTN gene links a higher rate of normotensive glaucoma due to a deficient protective protein for the optic nerve.
Normotensive glaucoma also seems to have something to do with spasm of blood vessels, called vasospasm. This has been studied by various doctors, including Dr. Craven, using blood flow instruments. It is very hard to measure the blood flow to the optic nerve with conventional ultrasound (Doppler) technology. Because of the spasm, it has similarities to migraines and a lot of glaucoma doctors feel that migraines are a risk factor for normotensive glaucoma.
Normotensive Glaucoma Evaluation.doc
Effect of Ginkgo Biloba Extract on Preexisting Visual Field Damage in Normal Tension Glaucoma in Ophthalmology, February 2003.Uveitic Glaucoma
Uveitic Glaucoma is when inflammation of the eye causes redness, light sensitivity and decreased vision. Inflammation causes white cells to form in the front and/or back of the eye. This inflammation can occur after trauma, surgery or from unknown causes (up to 50% of cases). Other causes include infections such as viruses, or systemic autoimmune illnesses such as sarcoidosis or rheumatoid arthritis.
Inflammatory or uveitic glaucoma consists of optic nerve damage from high eye pressures due to chronic inflammation in the eye. The eye pressure can go up or down during acute inflammation. If the white cells get trapped in the drain (or trabecular meshwork) of the eye, the eye pressure can rise. Additionally, the drain itself can swell causing the fluid to back up inside the eye. Sometimes the pressure can go down since inflammation causes release of prostaglandins, which increases the fluid flow out of the eye.
Inflammation inside the eye can also cause surfaces to stick to each other. This can lead to scarring within the eye between the iris and lens and/or the iris and eye wall. If the fluid gets trapped behind the iris because of heavy scarring, the eye pressure can acutely rise. This situation is called pupillary block glaucoma and requires laser or surgical treatment. When the scar tissue develops between the iris and eye wall, chronic angle closure glaucoma ensues (the angle or drain is closed from scar tissue) which can be treated medically or surgically.
Steroids and aqueous suppressants are used to treat inflammatory glaucoma. If eye pressure cannot be controlled with medical therapy then surgical options are explored, including trabeculectomy or tube shunt.
Glaucoma Suspects generally have a higher than average eye pressure. They may also have a family history of glaucoma or other risk factors for developing glaucoma, such as suspicious looking optic nerves. A glaucoma suspect will not have obvious nerve damage or visual field defects. Glaucoma suspects may or may not develop glaucoma over time so they should be monitored on a regular basis.
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Glaucoma Treatments
There are a wide range of treatments for the disease, including medication, laser surgery and traditional surgery. The treatment (or combination of treatments) for an individual is chosen based upon the type of glaucoma and other details of the particular case.
Medication - Glaucoma can be treated with medications such as prescription eye drops which help to reduce intraocular pressure, or pills called carbonic anhydrase inhibitors which slow down fluid production within the eye.
Laser Surgery has also become a common treatment option for glaucoma. For open-angle glaucoma the doctor may choose a trabeculoplasty, a painless laser procedure which uses light to shrink and stretch eye tissue to allow more drainage of fluid. For closed-angle cases, in which the iris is blocking drainage of aqueous humor, a laser surgery called iridotomy may be preformed.
Traditional Surgeries - Other glaucoma treatment options involve various traditional surgeries. A common surgery for open-angle glaucoma is the trabeculectomy, where a doctor creates a small flap in the sclera (white part of the eye). Underneath the surface of the sclera, the doctor creates a small reservoir, called a filtration bleb, into which aqueous fluid may drain and then be disbursed, further reducing intraocular pressure.
Surgical Options - Trabeculectomy
New Surgeries & Treatments - The following links are the latest surgeries, procedures and products for treating glaucoma. All are available at Specialty Eye Care - please contact us today at 303.794.1111 to schedule a consultation.
Glaukos: New glaucoma surgery being evaluated by the FDA: Denver, Colorado, USA: E. Randy Craven implanted the first Glaukos iStent for open angle glaucoma in the United States (Jun 2005). See on YouTube information about the procedure and what it looks like. Recently at the American Glaucoma Society Meeting in 2009, Dr. Craven presented the two year data from the Europe study on Glaukos iStent.
See the implant: Glaukos iStent Implant
See the 2 year data on the study: American Glaucoma Society Poster 2009 on Glaukos.pdf
Canaloplasty
Lumenis SLT
AquaFlow
Glaucoma Drainage Devices
SOLX 790 Laser
Trabectome Surgery
There are a number of treatments available for Glaucoma patients. If diagnosed with glaucoma, your ophthalmologist will consult with you on your options in order to maintain the best possible health of your eyes.
Surgical Instructions and Documents for Patients
Preoperative Surgery Check List.pdf
The Stages of Recovery From Glaucoma Surgery.pdf
Postoperative Instructions.pdf
Postoperative Routines & Activities.pdf
Advice for Patients - The Supporting Rationale.pdf
Glaucoma Overview for Patients.pdf
If you are experiencing any symptoms of glaucoma, we encourage you to contact us today at 303-794-1111 to schedule a consultation.
Specialty Eye Care Ophthalmologists, Abdulfatah M. Ali, M.D., E. Randy Craven, M.D., C. Starck Johnson M.D. and John Samples, M.D. - Locations in Denver and South Suburban area of Colorado.
Glaucoma Definition, Suspects, Treatments, Procedures and information on Open Angle Glaucoma, Angle Closure Glaucoma, Low Pressure Glaucoma and Uveitic Glaucoma.