Suncoast Eye Surgery Institute of Citrus River, Florida
There are several different types of glaucoma, but all types are caused by increased pressure within the eye that can destroy the optic nerve if not treated promptly.A constant level of liquid called the aqueous humor is maintained in the inner chamber of the eye. Fluid flows into the eye at a spongy outlet located at the angle where the cornea and sclera meet. If the outlet is clogged or if the drainage system is overwhelmed by too much liquid production, a buildup of fluid occurs and causes a pressure increase inside the eyeball.
This places pressure on the optic nerve and its blood supply that can cause serious irreversible damage.A blockage in the drainage system (and the resulting increase in pressure) can be caused by eye injury, tumor, hemorrhage, or infection.
WHAT ARE THE SYMPTOMS OF GLAUCOMA?
The symptoms of glaucoma vary depending on the specific type of glaucoma:
CHRONIC OPEN-ANGLE GLAUCOMA
Chronic open-angle glaucoma, is the most common type of glaucoma. This type of glaucoma primarily occurs in those persons over age forty and is symptomless a “quiet” disease that often causes irreversible damage before it is discovered.
Chronic open-angle glaucoma may develop as a result of gradual aging, causing a decreased drainage capacity. When drainage is reduced, pressure within the eye slowly mounts, harming the optic nerve.
Congenital Glaucoma is present at birth or shortly after birth. It is usually caused by a defect in the drainage system. Any infant who has symptoms of increased sensitivity to light or eyes that fill up with tears easily should be evaluated immediately to determine the nature of the problem and to prevent permanent damage to the sight.
ACUTE ANGLE-CLOSURE GLAUCOMA
Acute angle-closure glaucoma, also known as narrow-angle or acute glaucoma, results fro an immediate, complete blockage of the drainage area. The iris may press against the drain area causing sudden obstruction. Without drainage, fluid backs up and eye pressure increases rapidly. Rainbow like halos or circles around lights, severe pain in the eyes or forehead, nausea, and blurred vision may occur. This type of glaucoma can occur suddenly at any age and is a true medical emergency; immediate professional care is needed to preserve sight. Blindness can result quickly in a day or two without treatment.
Secondary glaucoma occurs as the result of some other health problem of the entire body or of the eye. It may develop rapidly or slowly. If closure of the drainage system occurs rapidly, the symptoms will be similar to those described for acute-angle closure glaucoma. Immediate attention by an eyecare professional is needed.
HOW IS GLAUCOMA DIAGNOSED?
Prevention involves early detection through a comprehensive eye health examination, especially after age 35. Sometimes the level of pressure may be above normal, yet there are no symptoms, so an eye examination is the only way to discover the problem.
During a comprehensive eye health examination an instrument called a tonometer is used check the level of pressure in the eye. It is a simple painless test that takes a fraction of a second to perform.
As part of your eye examination, your eyecare professional can also determine the health of the optic nerve by examining the inside of the eye.
In addition, visual fields are performed to determine the presence of blind spots or shrinkage in the peripheral field of vision.
People with a family history of glaucoma are more likely to develop the problem, as are those who are nearsighted.
Some diseases that impact the entire body, such as diabetes, anemia, or hardening of the arteries, increase the risk of the condition. Persons who do not actually have diabetes, but have a strong family history of the problem, should have their eyes checked frequently for early development of the disease.African-Americans tend to develop glaucoma more frequently than other racial groups.
Damage to optic nerve fibers cannot be reversed. For that reason, sight can only be protected through early detection of the problem. Since glaucoma may grow worse without symptoms, periodic eye examinations for those over age 35 are imperative.
The goal of glaucoma treatment is to prevent further damage and to preserve the highest possible level of vision. Glaucoma is treated by reducing the pressure within the eye. Medications, both pills or eye drops, are used to lower pressure either by causing better drainage of liquid or by decreasing liquid production. Medication usually must continue for life and must be taken regularly to effectively reduce eye pressure.
If medication does not reduce pressure, surgery may be recommended to correct drainage problems. The goal of surgery may be either to form a new drainage channel or open the old channel.
Since glaucoma cannot be prevented, the next best measure to protect sight is early detection and treatment before optic nerve fibers have been destroyed. This can be accomplished only through regular comprehensive eye health examinations, because glaucoma often is symptomless.
Everyone over the age of 35 should be tested for glaucoma every 1-2 years or whenever problems arise.
WHAT IS MACULAR DEGENERATION?
The macula is located in the center of the retina, it is the micro-thin membrane that lines the back inside of the eye. The retina has millions of light-sensitive nerve cells that capture images focused on the retina. These captured images are transmitted to the brain by the optic nerve.The retina performs two separate vision functions: central and peripheral. Central vision originates in the macula and is needed for highly-focused, straight-on tasks, such as reading, driving a car, or operating a computer. The rest of the retina's nerve cells handle peripheral vision.
Any damage to the macula will result in some or even total loss of central vision. Since peripheral vision is not affected, people with macular degeneration can adapt to the loss of central vision by learning to use their remaining peripheral vision. To focus on a particular object, the person must turn his head to the angle required to bring peripheral vision into play.
Most cases of macular degeneration develop after age 50. For this reason, the disease is often referred to as age-related macular degeneration or ARMD. There are two types of macular degeneration: The Dry Form and The Wet Form.
DRY FORM OF MACULAR DEGENERATON
About 90 percent of those who have ARMD experience this simple form of deterioration of the macula. Usually, the process happens over a period of months or years and may affect only one eye. Because the “good” eye gradually takes over the central vision functions of the “bad” eye, the victim is usually not aware of the loss of central vision in the affected eye until there are symptoms. The person may notice more difficulty seeing with one eye than the other, distortion of straight lines, or small dark spots appearing in the field of vision.
At this time, effective medical treatments are limited. Along with certain low-vision aids and devices, the best treatment is learning to use the remaining peripheral vision to compensate for loss of central vision.
WET FORM OF MACULAR DEGENERATION
Although only about 10 percent of all age-related macular degeneration victims are diagnosed with the wet form of the disease, it accounts for 90 percent of the most serious loss of vision cases. In the dry form, the loss of central vision tends to be gradual. In the wet form, the deterioration of central vision can be serious and rapid. This occurs when tiny blood vessels in the micro-thin layer of tissue beneath the retina begin to degenerate with age causing tiny leaks. This can cause swellings and breaks or lesions in the retina, damaging the retina's light-sensitive nerve cells.
Lasers have been used in treating this form of ARMD, but usually the best result is a slowing down of the deterioration process. The laser is used to cauterize the leaking blood vessels and/or “tack” the detached retina back into place. A diagnostic procedure used to determine the best course of treatment allows the doctor to tell if there is hemorrhaging in the retina. It is known as a fluorescein angiogram. Both procedures are virtually painless.
As with all eye disorders, early detection leads to more effective treatment. A thorough annual eye exam is the best protection for your vision.
WHAT IS DIABETIC RETINOPATHY?
As the name implies, diabetic retinopathy is a potentially serious disorder that affects the retina, the micro-thin membrane that contains millions of light-sensitive nerve cells and covers the back three-quarters of the eyeball. The retina receives images that are focused on its surface by the cornea and inner lens. These images are transmitted to the brain via the optic nerve, thereby creating the miracle of sight. Any damage to the retina will result in diminished vision capabilities, or in the most severe cases, the loss of central vision or even total blindness.
There are two types of diabetic retinopathy: background diabetic retinopathy and proliferative diabetic retinopathy. The proliferative type is the advanced stage of the disease and fortunately affects only about 5 percent of all diabetics, mostly those who have had diabetes for 25 years or more.
One of the complications of diabetes is the weakening of tiny blood vessels that nourish the retina. When this happens, some of the blood vessels begin to leak fluid (serum) and blood, thereby reducing the nourishment provided to the retina. Some may also hemorrhage or leak fatty or protein deposits. When this occurs in the peripheral areas of the retina, the loss of vision is usually gradual and treatable. In the early stages, the individual may be unaware of the presence of the disease until a regular eye examination has been performed. However, if the macula is affected, serious vision problems can develop. Although it is only about one-forth inch in diameter, the macula is responsible for all of the eye's central vision functions. The rest of the retina performs peripheral vision requirements.
With proliferative diabetic retinopathy, blood vessels may leak into the vitreous humor, the clear, jelly-like fluid that fills the inner cavity of the eye. This leak can cause a cloudiness of vision. Another problem is created when connective scar tissue forms from damaged blood vessels. Over time, this tissue can shrink and exert a pulling effect on the retina. This can result in a retinal detachment, another serious side effect of proliferative diabetic retinopathy.
WHAT ARE THE SYMPTOMS OF DIABETIC RETINOPATHY?
Individuals with background diabetic retinopathy may experience little or no noticeable loss of vision or any other perceivable problems. Therefore, the only sure way to determine the presence of this eye disorder, which can become much more serious with age, are regular eye examinations.
Those with the advanced form of the disease - proliferative diabetic retinopathy – will most likely experience some noticeable loss of vision, including cloudiness, distortion of familiar objects or loss of central vision capabilities. Blind spots or floaters may appear periodically in the field of vision as well. The probable cause of these vision problems is blood leaking from abnormal new vessels that have grown to replace those damaged by the disease.
If during a routine eye examination, your doctor detects any symptoms of the background or proliferative forms of the disease, he may decide to perform additional procedures to detect any abnormalities that might be present. Ultrasound equipment may also be used to check for the possibilities of retinal detachment.
WHAT IS THE TREATMENT FOR DIABETIC RETINOPATHY?
In the early stages of background diabetic retinopathy there may be no need for immediate treatment, but the disease should be carefully monitored by regular eye examinations in accordance with your doctor's advice. If the condition becomes more serious, a laser may be used to seal leaking blood vessels and thereby slow down their development into the more serious form, proliferative diabetic retinopathy, which is subject to the same type of treatment. As with macular degeneration, use of heat-sealing lasers to cauterize leaking blood vessels in the macular area of the retina must be done with great caution in order to prevent additional damage to the macula.
With all serious eye disorders, early detection by regular eye examinations results in more effective treatment, especially for a disease that is progressive in nature, such as diabetic retinopathy. If you have diabetes mellitus, you should have a thorough eye examination at least once a year. It is important to note that such factors as pregnancy, high blood pressure, smoking and diets rich in fats increase the chances of developing diabetic retinopathy. When you come in for your examination, we will be happy to answer any questions you may have and provide more information on this relatively common eye problem that can become serious in nature as the years progress.