Focus on Age-Related Macular Degeneration (AMD)
Published in THE IOWA LION September, 1999
By Beverly Collins, Marshalltown Noon Lions Club
Most people work hard all their lives, save, and look forward to the day they can retire and do the many things that have been put on hold. But for many, Age-Related Macular Degeneration (AMD) sets in, and the loss of vision that ensues greatly diminishes the plans and dreams they had worked so hard to achieve. AMD, a degenerative disease of the retina, is the leading cause of irreversible blindness in adults over age 60, affecting greater than 15 million people.
As people are living longer and AMD is more correctly diagnosed and reported by ophthalmologists, the percentage of older adults affected has reached a startling and significant proportion in America and other developed countries. The number of people affected is expected to rise dramatically to more than 30 million by the year 2010. It is estimated that at least one- third of the population over the age of 60 will display AMD.
What is most amazing about AMD is that only twenty years ago very few people were diagnosed with the disease. But it has recently become one of the most challenging eye disorders and causes of vision impairment encountered by the medical community. Dr. Troy Moats, a Marshalltown Noon Lion and a local ophthalmologist, notes he sees two to three cases of AMD per day in his practice.
What is Age-Related Macular Degeneration?
The disease Macular Degeneration appears to be human species. To date, no other animal model has been found that displays the characteristics of AMD in the same fashion as in man. In the back of the eye, on the retina, is a small area called the macula. The macula is only 6 mm in diameter and 100 microns thick. Sight receptors located in the macular region "see" what is in the direct line of vision. People with AMD typically have yellowish-white deposits on their macula called drusen, which cause the area to degenerate and dysfunction. This type of AMD is called the dry form and loss of sight from drusen-induced degeneration is usually gradual, with the center of vision becoming increasingly blurry, and affects nearly 90% of the people with macular degeneration.
The other form of macular degeneration, the wet form, occurs when a neovascular event occurs. This type of macular degeneration is much more severe but affects only 1 in 10 AMD patients. Blood vessels grow behind the macula and leak or burst. The photoreceptors die within a short period of time causing a person to go from sight to blindness within a day or so. Typically this form of AMD affects both eyes over the course of about five years. There has been some success with laser treatment of wet AMD; however, laser surgery merely stops the vessels from continuing to hemorrhage but does not restore or improve any vision loss that has occurred.
UIHC leads the way in AMD research
Only recently have significant research efforts to understand Age-Related Macular Degeneration begun. Two years ago a number of prominent researchers and physicians working on the disease were brought together at the University of Iowa Hospitals and Clinics to create the University of Iowa Center for Macular Degeneration, a Center dedicated to the research and treatment of macular degeneration. Dr. Gregory Hageman, a primary member of the research team, along with 10 faculty and over 100 technicians, were proud to unveil an impressive 12,000 square foot facility on the Oakdale campus and share the excitement of the groundbreaking research via the Center for Macular Degeneration Symposium. The array of equipment, including a new $350,000 high-tech electron microscope, phosphoimagers for genetic studies, and -80° cryogenic freezers is impressive.
Dr. Hageman's research focuses on studying the retinal region of human donated eye tissue. Thus, the cooperative relationship with the Iowa Lions Eye Bank to provide research eye tissue is essential for understanding the complexities of AMD with the hope that therapies and a cure can be found. The challenge for the eye bank is that the eyes for AMD research must be recovered and placed in a special fixative formula within four hours of death. Therefore, donations from the Iowa City and Cedar Rapids areas are currently being used for this specialized research project. Eyes recovered from other parts of Iowa will be used for other research projects into eye disorders that do not require such prompt recovery and preservation of the eye tissue.
Dr. Hageman's research team has collected hundreds of pairs of eyes on which to study AMD. Some eye tissue samples collected date back 10 years. "We can do so much with that one little piece of tissue," notes Hageman. With so many sets of cryopreserved human eyes, Hageman's team has the ability to compare a specific piece of eye tissue with thousands of others. The team can examine diseased eye tissue compared to healthy tissue and ask the question "What is different about these two sets of eyes?"
One of the first areas for Hageman's research has been to investigate the drusen deposits on the retinas of donors with AMD. While ophthalmologists have long been aware of drusen formation on the macula, very little research has taken place to understand the biochemical makeup of these deposits. Hageman's staff is trying to determine exactly what they consist of and what causes them to develop on the macula. So far the deposits have been found to be very similar to the protein deposits in atherosclerotic plaque and heart disease, as well as Alzheimer's plaque. There also appears to be a cellular component to the drusen deposits, which might indicate an auto-immune response factor at work. And finally, there appears to be a correlation between macular degeneration, and smoking and between abdominal aortic aneurysms.
Recently there has been a lot of media attention surrounding the promotion of dietary supplementation as a quick fix and cure- all for eye disorders. It remains to be seen whether vitamin and mineral supplements can prevent AMD or slow its progression. The extent to which supplements affect AMD has not been clinically established; however, it is important to eat a wide variety of fruits and vegetables for overall health.
Iowa Lions play significant role in aiding research
Lions clubs throughout Iowa have provided the foundation and support necessary to create the success of the Iowa Lions Eye Bank. Lions groups from across Iowa provided significant funding to develop the Iowa Lions Eye Bank, one of the country's first charter eye banks to restore sight through corneal transplantation since 1955. Now the eye bank provides the driving force to procure eyes for AMD research. Hageman notes how unique the state of Iowa is, so, giving, so cooperative. "None of what I do would be possible without the assistance and cooperation of the Iowa Lions Eye Bank," says Dr. Hageman.
The National Institutes of Health, the National Eye Institute, and other local and federal agencies monetarily support the research efforts of the University of Iowa Center for Macular Degeneration. Also, pharmaceutical companies are joining the efforts to find medical therapies to prevent and treat AMD, and therefore fund the research as well. These groups are very interested in the genetic component of AMD and are committed to mapping all of the human genes in the future. Currently, 40,000 genes have been mapped with several playing a role in the AMD disease process. The next few years promise to yield more discoveries and hopefully more answers to this baffling and devastating eye disease.
Iowa Lions can be proud of their role in helping to make this research possible. We give thanks to the donors and donor families who make the courageous decision to donate. One donor family member eloquently stated, "This is the greatest thing I could have done. " In addition, thanks must be given to all Iowans who support the belief that "no level of blindness is acceptable in our society."
For an appointment or further information regarding the University of Iowa Center for Macular Degeneration, please call (319) 384-9271.
(Thank you to Sara Baker and Dr. Hageman for their review and editing.)