Hope exists for newly diagnosed
By Jeff Hansel
jhansel@postbulletin.com
There is currently no effective treatment for severe vision loss from macular degeneration -- a progressive loss of vision caused by a degradation of the eye's macula, which helps people see.
But there is hope, especially for those who are newly diagnosed.
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Normally, said Dr. Colin McCannel, a specialist in diseases of the retina at Mayo Clinic, prevention is the preferred treatment. Once severe damage to the macula has occurred, treatment options are slim.
But McCannel said researches continue to search for treatments on many fronts. There are two clinical trials studying the use of lasers to reduce or remove damaged areas of the macula. Does the laser alter what happens to a person's eye?
"Within the next couple years, we'll have an answer to that," McCannel said. The problem, of course, is that laser treatment directly to the affected area can affect vision just like macular degeneration (MD).
If the treatment saves more than it takes away, it may be preferred to current methods. Right now, people dealing with loss of sight receive help adjusting to their vision loss. But researchers hope to offer treatment.
There are two forms of MD -- dry and wet. Dry macular degeneration can not be treated. Vision loss is progressive -- but slow. Wet MD, on the other hand, is more treatable the earlier it is caught.
Other possible treatments for wet disease include:
Standard hot laser treatment.
"It's better to do that than to not do anything at all, but it's a lousy treatment," McCannel said.
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Photodynamic therapy closes blood vessels. But multiple treatments are needed and there is still less vision than desired.
Medications to block blood vessels called antiangiogenic compounds. There are currently at least three different ones under investigation, McCannel said. They're injected into the eyeball to block blood vessel growth. This allows a high concentration of the medication in the eye with minimal amounts of the medication found elsewhere in the body.
Retinal shift uses surgery to move the retina and then treat the underlying blood vessel growth. But "anybody who's had poor vision for a long time is absolutely not a candidate at this time in terms of treatment," McCannel said.
One myth, McCannel said, is the idea that people can get eye transplants. There is no such thing, he said. Once vision is lost for a long time as a result of macular degeneration, "there is nothing that will recover the vision." The best practice, he said, is to treat the disease as early as possible with the best treatment available at the time.
"If patients know they have macular degeneration or they're older than 50 years old and they all of a sudden notice their vision isn't quite right, they should probably be seen for an urgent eye evaluation," McCannel said.
Down the road, he said, gene therapy to make vessels stop growing are likely, but that scientific work is still in its infancy, although one clinical trial is in the beginning phases.
"The next generation is all these anti-vegF compounds," McCannel said. They are used to stop or slow down vessel growth. Twenty to 30 years from now, he said, grandparents who have macular degeneration now can be assured that there will be much better treatment options available if their grandchildren get macular degeneration. But, again, such treatments are a ways off.
There are two known genes that cause macular degeneration in a very, very small number of the total cases. But researchers have yet to explain how the inheritance works.
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"Until we understand which genes are defective, we will not have gene therapy," he said.
When people get severe vision loss, they usually have wet disease, he said.
"There's no treatment for dry disease at this time," he said. Wet MD, McCannel said, can be considered a complication of dry disease. The unfortunate aspect, however, is that wet disease can lead to blindness. Preventive vitamin supplementation can work, McCannel said, by reducing the risk of vision loss.
"This is high-dose vitamin supplementation and people should let their primary doctor know that they are taking them," he said.
People with vision loss, McCannel said, should seek low-vision services from places like the State Services for the Blind in Rochester (285-7282).
BOX: Symptoms
Macular degeneration causes different symptoms in different people.
It might hardly be noticed in early stages. One eye might remain healthy for years while the other loses vision. But when both eyes lose vision, loss of central vision might be noticed more quickly.
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Common ways vision loss is detected include:
Words on a page look blurred.
A dark or empty area appears in the center of vision.
Straight lines look distorted.
Source: American Academy of Ophthalmology
BOX:Unproven remedies
Even though they are recommended by various sources, there is no scientific evidence that lutein supplements, eating spinach, taking bilberry extracts or other compounds and supplements helps prevent vision loss from macular degeneration.
Source: Mayo Clinic, Dr. Colin McCannel
