The Dilemma of Macular Degeneration
According to Baily and Hall, while visual impairment early in life is associated with inherited congenital disorders, abnormal fetal devepment, and problems associated with premature birth, most eye conditions are associated with aging. They claim that over 70% of the visually impaired population in the United States is over 65. Age related maculopathy, also called macular degeneration, or AMD, impairs the center of vision in older individuals. The macula is the region in the back of the retina that surrounds and includes the fovea (Goldstein 1999). It is important to understand that when this degeneration progresses enough, the condition constitutes blindness because the foveal area is what is used to focus on something. Most cases do not progress this far, but between five and 20% do. Allikments and Shroyer claim that 11 million people in the United States alone suffer some degree of this impairment, with 75% of those individuals being 75 or older. Seven percent of this older age group reportedly suffer advanced forms. Freidman reports the disease as most common in developed countries.
The high percentages of individuals who endure this impairment justifies and practically demands future research because the causes are not fully understood. The need for future research can be better emphasized if those with normal vision try to empathize with victims of macular degeneration. One can only imagine how frustrating it must be to receive sensatrions only in the periphery of the retina. Because the macula encompassed the cone rich fovea, which is used to focus on objects, the fovea degenerates as well. This occurence inables individuals to interpret the sensations they experience. Reading, recognizing faces, and driving are visual tasks most people take for granted that become very difficult when the central vision is disturbed (Baily & Hall 1989). Danger can exist for victims of the condition when simply walking down the street or even through their own homes. While there is yet no cure for macular degeneration the research is in progress. Two main areas of research include investigating the causes and exploring potential treatments.
According to Friedman, progress in the effort to stop or prevent AMD will be slow until the cause is learned. He claims retinal pigmant epithelium damage to be the prominant theory explaining the choroidal circulation changes that lead to AMD. Although Friedmal himself does not subscribe to this theory, other researchers do and use it as a basis for study. Grunwald, Harisprasad, Dupont, M. G. Mguire, Fine, Bruker, A.M. Maguire, and Ho compared choroidal blood flow in subjects with AMD to a control group. They used laser doppler flowmetry to asess the volume, velocity, and flow of blood in the center of the fovea. Ten subjects with no drusen (cellular debris) were compared to 20 subjects with ten or more large drusen. The average visual acuities of the two groups was very...