The macula is part of the light-sensitive retina at the back of your eye. It's responsible for sharp, direct vision needed to read or drive. This disease causes the macula to break down and degenerate, resulting in gradual or sudden loss of central vision.Macular degeneration is diagnosed as either dry (atrophic) or wet (exudative). The dry form is more common than the wet, with about 90% of ARMD patients diagnosed with dry ARMD. This form may result from the aging and thinning of macular tissues, depositing of pigment in the macula or a combination of the two. With wet ARMD, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes retinal cells to die and creates blind spots in central vision.
Causes
Most cases of macular degeneration are age-related, meaning older people are more likely to have it. Some cases are side effects of toxic drugs such as Aralen (chloroquine, an anti-malarial drug) or phenothiazine. Phenothiazine is a class of anti-psychotic drugs, including Thorazine (chlorpromazine, which is also used to treat nausea and vomiting, and intractable hiccups), Mellaril (thioridazine), Prolixin (fluphenazine), Trilafon (perphenazine) and Stelazine (trifluoperazine).
Risk factors include: being white or female, having a family member with AMD, smoking, high blood pressure, farsightedness and obesity. The exact causes are still unknown.
Symptoms
Macular degeneration can produce a slow or sudden painless loss of vision. Some early signs are straight lines appearing wavy, fuzzy vision or shadowy areas in your central vision. Peripheral and color vision are not affected.
While ARMD causes severe central vision loss, ARMD patients are not completely blind in the sense of seeing nothing but blackness. An easy way to know what an ARMD patients sees is to hold your closed fist a few inches away from one eye while keeping the other eye closed. What you see around your fist is the vision of most later-stage ARMD patients.
Sometimes your eye care practitioner can detect early physical indicators of macular degeneration before you experience symptoms. If this disease runs in your family, be sure to visit your eye care practitioner regularly.
Most Common Treatments
Many researchers and eye care practitioners believe that nutrition plays a role in lowering the risk for ARMD or halting the progression of dry ARMD. Zinc appears in high concentrations in the retina, especially the macula. Some research suggests that zinc supplements may help ARMD patients, especially as many elderly people have a zinc deficiency.
Antioxidant vitamins, such as beta carotene (vitamin A) and vitamins C and E, are also thought to protect the macula from damage. Keep in mind that too much of any vitamin or mineral may affect the body's ability to absorb other important nutrients, and the eye care community does not agree on the benefits of zinc or antioxidant supplements.
Although a lot of progress has been made recently in ARMD treatment research, as things stand now, any central vision lost to dry ARMD will probably not be restored. Your eye care practitioner may ask you to check your vision with an Amsler grid, a piece of paper with a black grid of lines. Viewing the Amsler grid separately with each eye helps you monitor your vision loss. Scientists are currently studying laser treatments for dry ARMD.
Early diagnosis and treatment for wet ARMD can prevent further vision loss. The Food and Drug Administration has recently approved Visudyne™, the first-ever drug therapy for wet ARMD. It's only for those whose new blood vessels are characterized as "predominantly classic": about 40% to 60% of new wet ARMD patients, according to Visudyne maker CIBA Vision. Here's how it works: the doctor injects Visudyne into your arm, then activates the drug by shining a laser into your eye. In clinical trials, 67% of patients found that either their vision loss stabilized or that their vision improved.
Laser photocoagulation may help wet ARMD patients by destroying new blood vessels to prevent leakage.
For those who have suffered vision loss, many low vision devices are available to help improve vision by using magnifying lenses and bright lights. Some low vision aids shift images to the periphery for clearer vision.
