Age-related macular degeneration (AMD) is a chronic eye disease that results in damage to the macula. The macula is located inside the eye - in the center of the retina, the light sensitive tissue at the back of the eye. The retina's function is to convert light or images into messages for the brain. Damage to the macula causes blind spots or blurriness in the center of the person's vision. The outer fields of vision are not affected, so AMD does not cause total blindness. However, the loss of central vision strongly affects the person's routine activities since central vision is necessary for reading, driving, recognizing people's faces and doing other kinds of detailed work.
If you experience the following, see your eye physician right away to rule out AMD:
AMD is detected with a thorough eye exam. The damage caused by macular degeneration cannot be reversed, but early detection may reduce further vision loss. The exact cause of AMD is unknown, but risk factors for the disease include being 50 years or older, of the Caucasian race, having a history of cigarette smoking, having a family history of AMD, and being a female.
There are two forms of age-related macular degeneration. Dry macular degeneration is the most common form of this disease. Early AMD is associated wit the formation of small yellow deposits, called druses, under the light-sensing cells in the retina. Late cases of dry AMD may also involve thinning and drying out of the macula.
The most common symptom with dry AMD is slightly blurred vision, and the symptoms usually affect both eyes. Macular degeneration always starts out as the dry form. The dry type of AMD may progress to the wet type over time.
The wet form of AMD is considered advanced AMD and is more severe than the dry form. Wet AMD results from the growth of abnormal blood vessels under the macula in the back of the eye. With wet AMD, loss of central vision can occur quickly. One early sign of wet AMD is that straight lines appear wavy.
As the average lifespan of our population increases, the number of people developing AMD is expected to increase dramatically.
Dry Age-Related Macular Degeneration
At this time there is no cure for dry age-related macular degeneration. Treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage with vision loss. The National Eye Institute's Age-Related Eye Disease Study (AREDS) found that taking a high-dose combination of antioxidants and zinc reduced the risk of advanced AMD.
Wet Age-Related Macular Degeneration
Once AMD reaches the advanced stage, no treatment can prevent vision loss. There are two treatments to reduce the progress of wet AMD -- laser surgery (i.e., photocoagulation) and photodynamic therapy. While neither treatment is a cure, either may slow the rate of further vision loss.
Laser surgery or photocoagulation uses a high-energy laser to destroy the abnormal, leaking blood vessels. Only a small number (about 5 out of every 100) of people with wet AMD can be treated with laser surgery. The location that needs to be treated will determine if the laser is the right choice for treatment. Repeated treatments may be necessary. Laser surgery is usually performed in a doctor's office or eye clinic.
Photodynamic therapy involves the use of a cold laser in combination with a light-sensitive drug. The drug (verteporfin) is injected into the blood stream and is activated when the cold laser light is directed into the eye. The drug, which is made active by the laser, destroys the new leaking blood vessels in the eye. Unlike the laser surgery, this therapy does not damage other tissue in the eye. The therapy can be repeated and is usually performed in a doctor's office or eye clinic.
Will I live longer if I have treatment?
No, treatment will not lengthen your life.
Will the treatment of macular degeneration improve my quality of life?
Yes, the sooner wet AMD is detected, the better your chance of maintaining what is left of your vision. People with this disease may lose their ability to read, drive a car, and recognize faces. After laser surgery or photodynamic therapy, you will need frequent eye exams to detect any recurrence of leaking blood vessels.
There are no treatments for the early stages of dry AMD at this time. Fortunately, dry AMD usually progresses slowly. Treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage with vision loss. The specific high-dose combination of antioxidants and zinc, recently studies by the National Eye Institute, may reduce the risk of advanced AMD and vision loss. While this is not a cure for AMD it delays the onset of advanced AMD. By slowing the progression from the intermediate stage to the advanced stage, vision can be saved.
For wet AMD, success of treatment depends on the location and extent of disease. Generally, the damage already caused cannot be reversed. Only about 20% of people who have wet macular degeneration can be treated with laser surgery. Laser surgery is only successful in about half of all cases - 50% of the time. The risk for reoccurrence after laser surgery is high. Vision loss may progress even with repeated treatments.
Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision. Treatment results are often temporary and treatments may need to be repeated. People who smoke have a greater risk of recurrence than those who do not smoke.
Laser surgery does not guarantee that vision will be saved. Laser surgery is limited in effectiveness and may also destroy some of the surrounding tissue and vision.
Unlike laser surgery, photodynamic therapy does not destroy surrounding healthy tissue. Because the drug used is made active by light, you must avoid exposing your skin or eyes to direct sunlight or bright indoor light for five days after treatment.
The rate for any problems occurring from the treatments is low.
The alternative treatments, such as surgical excision and radiation therapy, are still unproven.
The average cost for the laser surgery / photocoagulation or the photodynamic therapy is over $5,000.
The cost may or may not be covered by your health benefits plan.
The following are off-site links :
American Academy of Ophthalmology. (2010, March). Are you at risk for age-related macular degeneration (AMD)? Learn the top 5 risk factors. Retrieved March 4, 2013 from http://www.aao.org/newsroom/release/20100303.cfm.
American Macular Degeneration Foundation. What is macular degeneration? Retrieved March 4, 2013 from http://www.macular.org/disease.html.
Mayo Clinic. (2012, November). Dry macular degeneration. Retrieved February Retrieved March 4, 2013 from http://www.mayoclinic.com/health/macular-degeneration/DS00284.
Mayo Clinic. (2012, December). Wet macular degeneration. Retrieved March 4, 2013 from http://www.mayoclinic.com/health/wet-macular-degeneration/DS01086.
Prevent Blindness America. National Eye Institute. (2008 update to the fourth edition). Vision problems in the U.S. Prevalence of adult vision impairment and age-related eye disease in America. Retrieved March 4, 2013 from http://www.preventblindness.net/site/DocServer/VPUS_2008_update.pdf.
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