The term "Glaucoma" describes a number of eye conditions that result in permanent damage to the optic nerve. Generally, glaucoma is thought of as a higher than "normal" intraocular pressure (IOP).
Although a high intraocular pressure is often a major cause of glaucoma, it not the only cause of glaucoma. In fact, there are many different types and causes of glaucoma. Regardless of the type or cause of glaucoma, if it is left untreated, glaucoma can cause permanent vision loss and possibly even blindness.
Between 2.5 and 3 million people in the United States have been diagnosed with glaucoma and another 1 million individuals in the United States probably have glaucoma, but have not yet been diagnosed because they do not have access to eye care. In the United States alone, there are approximately 100,000 patients who are believed to be legally blind from glaucoma. Among adults aged 18-65 in the United States, glaucoma is considered the second leading cause of blindness.
Glaucoma is so threatening because of its slow and progressive onset that usually does not cause patients to experience any visual symptoms or discomfort. Patients can walk around and not know that they are gradually losing their vision until glaucoma is at a very advanced stage.
Glaucoma is best found and diagnosed during routine comprehensive eye examinations. At a minimum, anyone over the age of 50 years old should be screened for glaucoma every two years. If there is any family history of glaucoma, patients should be screened every year beginning at 40. Siblings of glaucoma patients are at particularly high risk for developing glaucoma and should be screened on an annual basis.
Causes & Types of Glaucoma
The cilliary body- a structure located inside your eye behind the colored part (the iris) produces a clear fluid called the aqueous humor. The aqueous humor supplies oxygen and nutrients to the tissues in the eye. Normally, the aqueous humor is drained through a meshwork of tissue that is located at the base of the iris. In most normal patients, the amount of fluid produced is equal to the amount of fluid drained. This equilibrium is what creates the "normal" pressure in the eye.
Primary Open Angle Glaucoma
The most common type of glaucoma is called Primary Open Angle Glaucoma (POAG). With Primary Open Angle Glaucoma, patients often have an elevated Intraocular Pressure (IOP) measurement that may result in damage to the optic nerve if left untreated. The elevated intraocular pressure usually
occurs because the rate of drainage of fluid through the meshwork is insufficient. It is this raised pressure (IOP) that can cause permanent changes and even damage to the optic nerve. The optic nerve is the critical communication pathway between the back of the eye and the brain and is responsible for transmitting signals and images. Once the optic nerve is damaged, it is not capable of regenerating, and this results in vision loss. Thus, it is important to monitor intraocular pressure regularly in order to detect and control elevated intraocular pressure. If left untreated, a high intraocular pressure (IOP) can, over time, lead to slow progressive, permanent damage to the optic nerve that can result in blindness.
Angle Closure Glaucoma
A much less common, but equally significant type of glaucoma, is called Angle Closure Glaucoma.
Angle Closure Glaucoma is characterized by closure or blockage of the drainage structure of the eye-the trabecular meshwork. The trabecular meshwork is really similar to a fine filter. If the filter becomes obstructed or blocked, the pressure can rise quickly and significantly. If the filter becomes closed suddenly, it will cause an acute rise in the intraocular pressure (IOP). This can cause pain, redness, blurred vision and if left untreated permanent loss of vision. There are several different causes of Angle Closure Glaucoma but the most common is Acute Angle Closure Glaucoma due to anatomic variations of the structures within one's eye. This is much more common in far-sighted eyes and is most prevalent between the ages of 45 and 60. If Drs. Berger, Howard and Kessler detect a narrowed angle during your routine eye examination, they may perform a special examination called a gonioscopy to evaluate your risk for Angle Closure Glaucoma.
Acute Angle Closure Glaucoma is most effectively treated with a laser in order to create a small hole in the peripheral iris tissue to redirect the aqueous fluid and prevent the trabecular meshwork from becoming blocked.
Glaucoma Risk Factors
There are a number of factors that may put patients at higher risk for developing glaucoma. Some of these factors are more significant than others, and some are highly predictive.
• Increased Intraocular Pressure-if you have been found to have an elevated intraocular pressure
during a routine eye examination or glaucoma screening, you are considered to be at greater
risk for developing glaucoma.
• Age-the likelihood of developing Glaucoma tends to increase with age, and in particular when
you are above 40-50.
• Race-certain genetic factors seem to predispose African-Americans to a higher likelihood of
• Myopia-the nearsighted eye has anatomical features that can increase the risk of Primary Open
• Hypertension-patients who are being treated for high blood pressure are at greater risk for
• Diabetes-as with hypertension, those being treated for diabetes are considered to be at greater
risk for glaucoma.
• Family History-if others in your family have been diagnosed with glaucoma, your risk of
developing glaucoma increases considerably.
Treatment of Glaucoma
Fortunately, today we have many excellent options for treating glaucoma. For purposes of this discussion we will limit our treatments to those used for treating Primary Open Angle Glaucoma, as it is the most common type of glaucoma.
Medical Treatment of Glaucoma
By far the most common form of treatment for glaucoma is the use of eye drops. In fact 80% of patients diagnosed with glaucoma can be successfully treated with one or more of a large list of prescription medications. These medications work by either decreasing the amount of fluid being produced inside the eye or by increasing the rate of drainage of fluid from the eye. In the vast majority of cases, by using the eye drops as prescribed 1-2 times per day it is possible to effectively control the intraocular pressure and the progression of the disease. Some patients may experience side effects or have reactions to these eye drops that make them a poor treatment option. Also, some patients just do not respond well to the eye drops and thus are unable to achieve adequate control with eye drops alone.
Laser Treatment of Glaucoma
For those patients who cannot be successfully treated with eye drops, laser therapy may be utilized to help control the intraocular pressure (IOP). In fact, today laser treatment for glaucoma is widely used to help prevent vision loss and is becoming a glaucoma treatment of choice for many patients who have problems with eye drops or are unable to instill them properly.
Argon Laser Trabeculoplasty (ALT) is a glaucoma laser treatment that helps to reduce the intraocular pressure by causing more effective drainage of fluid from the eye. It has been used successfully for many years. However, for some patients, the effect of ALT seems to diminish over time. This is
troubling, as ALT cannot be repeated. Another type of laser treatment for glaucoma is called Selective Laser Trabeculoplasty (SLT). This type of laser treatment is growing rapidly as a treatment method for glaucoma because it seems to be a bit gentler on the eye, and more importantly, should the effect be diminished over time, SLT can be repeated several times in order to control the disease and prevent vision loss. SLT is becoming an important treatment option not only for glaucoma patients who are unable to use eye drops or are not responsive to eye drops, but as a primary treatment method to possibly help Glaucoma patients avoid the need for eye drops altogether. Drs. Berger, Howard and Kessler perform SLT at the Litchfield Hills Eye Physicians office in Torrington.
Surgical Treatment of Glaucoma
Finally, in the event that patients are unable to achieve satisfactory results with either eye drops or laser treatment for glaucoma, there are surgical procedures that Drs. Berger, Howard and Kessler might recommend in order to help reduce and stabilize the intraocular pressure (IOP) and prevent vision loss. These include procedures such as trabeculectomy whereby the trabecular meshwork is dissected in order to help fluid drain more effectively from the eye.
As you can see, Glaucoma is a complex eye disease, but is successfully treated when found early in its course. Litchfield Hills Eye Physicians and its staff, under the medical direction of Drs. Berger, Howard and Kessler provide the full scope of diagnostic testing and treatment options as well as the patient education necessary in order to get the best possible outcomes for their patients. If you or a family member or friend have not had a recent screening and examination for Glaucoma, please take a moment to request an appointment so that you can be sure your eyes are healthy.