In the first effective treatment for the most common cause of vision loss in the Western World, a new national study finds the condition can be halted by high doses of vitamins and anti-oxidants.
The form of blindness known as macular degeneration affects some 1.7 million Americans. With no cure and limited treatment options, patients diagnosed with the disease had a grim outlook on the future for their vision.
It starts as a small dot in the center of the field of vision, then slowly spreads outward, eventually taking over the entire central vision. Everyday tasks — driving, reading, even seeing faces — become impossible.
But scientists have now found new hope. The researchers report that a high-dose supplement containing vitamins C and E, beta-carotene and zinc significantly decreases the risk of macular degeneration progressing to blindness. The study appears in the October issue of Archives of Ophthalmology.
Thousands at Risk for Blindness
The benefits of vitamin supplements on eye health have been suggested in the past, but this is the first study to offer supporting scientific data.
The six-year Age-Related Eye Disease Study, or AREDS, conducted by the National Eye Institute, followed 3,640 patients, ages 55 to 80, in 11 medical centers across the United States. Of the patients given the high-dose supplement containing the vitamins and zinc, development of advanced age-related macular degeneration, or AMD, was cut by 25 percent, the risk of vision loss reduced by 20 percent.
Of 1.7 million Americans who have some form of AMD, approximately 100,000 are currently blind from the disease, according to the National Eye Institute. The ailment affects approximately 30 percent of seniors aged 75 and above.
"Essentially this is a condition that affects a huge amount of people and up until now, there has been no effective treatment," says Dr. Emily Chew, principal AREDS researcher and deputy director of the Division of Epidemiology and Clinical Research at the National Eye Institute. Chew estimates 6.7 million Americans are at high-risk for developing AMD and could benefit from these findings.
Experts warn that as life span increases, the numbers will increase, too.
"As our population ages and goes into retirement, more will develop the disease. They will want to be able to enjoy life, watch their grandchildren," notes Eye Institute investigator Dr. Thomas Friberg, Professor of Ophthalmology and Director of the Retina Service at University of Pittsburgh. "This is a really important trial, it's really the first successful treatment of the disease."
A Cracked Sidewalk
Macular degeneration, appearing in two forms known as "wet" and "dry", is the gradual breakdown of the macula — the light-sensitive tissue at the back of the eye. "Dry" macular degeneration is noted by the breakdown of light detecting cells in the macula. "Wet" degeneration occurs when new blood vessels rupture and leak fluid behind the retina.
"The dry form is like an old sidewalk that develops cracks — wet is when grass grows up through the cracks," explains Friberg.
There are some laser treatments being performed in a small select group of patients with the wet form. But until now, the dry form, which affects 90 percent of all AMD sufferers, had been considered unreatable.
Supplements given in the study contain much higher amounts of the vitamins beta-carotene and zinc than a normal diet or even a daily multi-vitamin would provide — eight times the recommended daily allowance of vitamin C, 50 times vitamin E, five times the zinc and three times the daily recommendation of beta-carotene.
No major side effects or toxicity were noted within the group that took supplements, but a small number of participants did report urinary problems including urinary tract infections and kidney stones.
Experts recommend checking with a doctor before starting to take supplements at high-doses, and those aged 55 and over should have regular dilated eye examinations to determine their risk of developing AMD.