Macular Degeneration and New Treatments
Macular degeneration is one of the leading causes of vision loss among those over 65. The disease involves the deterioration of the macula -- the central part of the retina -- and results in the loss of central vision. This detailed vision is necessary for reading, driving, and even recognizing faces. Age-related macular degeneration (or AMD) results in a serious loss of independence and quality of life for sufferers of the condition.
However, in recent years, researchers have found promising new treatments for both types of macular degeneration, wet and dry. These treatments are now being tested, and hold out new hope for seniors diagnosed with AMD.
Treatments for "Wet” AMD
Wet AMD occurs when abnormal, leaky blood vessels grow behind the macula. Bleeding and scarring damages the eye's photoreceptors, often causing severe damage in a relatively short amount of time.
Previous treatments for wet AMD were laser surgery and photodynamic therapy. These proved somewhat effective, but laser surgery sometimes damaged healthy tissue, and photodynamic therapy had to be repeated very often. Latest treatments involve regular anti-VEGF injections into the vitreous humor of the eye. These anti-growth factor agents inhibit the growth of abnormal veins, and can cause improvement of vision.
Treatment for "Dry” AMD
Perhaps the most exciting research is being done on the "dry” form of AMD, which causes atrophy of the cells of the macular region. Previously, there was no medical treatment proven to cause improvement for dry AMD, but in 2001 a large study proved that vitamin supplements during the intermediate phase of dry AMD could slow the disease's progress. And now, recent studies on antioxidant carotenoids are showing promising results.
It's now thought that dry AMD may be caused by life-long oxidated insult, which leads to the death of photoreceptors in the central retina. Increased risk for AMD may happen due to insufficient levels of the carotenoids that make up macular pigment. This macular pigment is believed to shield photoreceptors from blue light, which causes photooxidation, and to fight free radicals, which proliferate in the area.
Several new studies featuring human subjects have used supplements of these carotenoids in an effort to increase density of macular pigment. One study gave subjects high doses of lutein and zeaxanthin; a second added meso-zeaxanthin to the mix. Both studies, which were broad-based and included a placebo control group, used flicker photometry to take measurements. And both studies showed increases in pigment density, in active groups, but not in placebo groups. No adverse effects on other organ systems were found.
Perhaps the most exciting findings were from the group that included meso-zeaxanthin in its study. MZ, as it's known, lutein, and zeaxanthin were supplemented in equal measures to some subjects. The mix proved to be much more effective than any of the carotenoids on their own, and more effective than the lutein-zeaxanthin mixture. Researchers hypothesize that although North Americans ingest relatively high levels of lutein and zeaxanthin through food, they don't get much MZ from their diets. This could mean that MZ deficiency is common, and may perhaps be a cause of AMD.
Further research is required, but it may be that these exciting breakthroughs in the treatment of age-related macular degeneration will lead to a cure in our lifetime.