The macula is the point of central vision on the retina needed for reading, driving, identifying faces, watching TV, and most other routine activities. AMD destroys the sharp central vision required for reading, driving and recognizing faces. Vision blurs and dims until only a ring of peripheral sight remains. At present 10 million Americans show signs of the disease. As many as 20% of people over age 60 develop AMD. Over age 75, the risk jumps dramatically to 40%. When the "baby-boom" generation reaches this milestone, we will be faced with an epidemic of perhaps 21 million Americans with vision loss from AMD.
With funding by the Dr. Henry and Lilian Nesburn Macular Degeneration Program and the Henry L. Guenther Foundation, researchers in the laboratories at the University of California, Irvine are looking into both the genetic and environmental influences that make a person susceptible to this eye disease.
There may be good news regarding human genes that may actually help in preventing this eye disease. Through the work of H. K. Hamdi, Ph.D., and his colleagues, our research has uncovered genes related to heart disease that appear to decrease the chances a person would get AMD.
Dr. Donald Brown and colleagues have been studying several human genes that appear to determine the likelihood that AMD will develop in an individual. One of these human genes, "ABCR", undergoes changes in its makeup and therefore, increases the chances of getting AMD. From the result of these and other genetic studies, it may be possible in the future to use these "helpful genes" by way of gene therapy in slowing down or even preventing the development of AMD in the eye.
In addition to studying the genetic causes of AMD, Dr. Ong and his colleagues are studying the two known AMD risk factors of smoking and elevated cholesterol. More precisely, they are trying to determine exactly how smoking and elevated cholesterol effect the structure and function of the retina.
It has been well known that both smoking and high cholesterol greatly increase the chance of getting heart disease. Dr. Ong and his colleagues have been trying to find out if smoking and elevated cholesterol influence the eye in a similar fashion to that of the cardiovascular system. The preliminary results from their studies indicate that these two particular risk factors appear to directly affect the cells in the eye and thus, impair the visual function. Further studies will reveal more information on how the eyes are affected by smoking and cholesterol and hopefully, help develop therapeutic strategies in the prevention of AMD.
