Age-Related Macular Degeneration...

Age-related macular degeneration (AMD) is the leading cause of visual impairment affecting the elderly patients over 50 years of age. Prevalence increases markedly after the age of 65 years. The . incidence continues to rise because of the increasing percentage of elderly persons and the improved management of other eye diseases. Based on recent studies done abroad, it is estimated that over 25 million people in North America, Europe, Japan, and Australia have some manifestations of AMD.

What is the Macula?

The macula is the central 6-7.5 mrn area of the retina, which in turn is the image-forming layer of the eye analogous to the film of a camera. The very center of the macula is called the fovea where the central, sharpest and most acute vision is served. It is this area which is utilized when one is reading, aiming, following moving objects or any other activity where clear and sharp' vision is required. AMD typically affects any area in the macula and may even extend outside its boundaries. Degree of loss of vision depends on the involvement or non- involvement of the fovea. The rest of the retina outside the macular area is the one responsible for peripheral vision, and this is almost always unaffected.

What are the treatment options? Can vision be restored?

The severe decline in vision in AMD is primarily related to the development of CNV with outright or subsequent involvement of the clinical fovea. Currently, the only treatment that has been shown to be beneficial based on studies is photocoagulation. However, only a small number of patients with CNV can be effectively treated by such modality. Majority of patients do not meet the criteria set to make laser treatment beneficial at reducing severe visual loss. New treatment strategies are aimed at limiting the degree and extent of destruction of retinal tissue overlying the CNV ~ especially the clinical fovea.

Surgical removal of the CNV (submacular surgery)~ selective destruction of CNV via low- intensity light exposure of tissues treated with photosensitizers to produce photochemical effects . with subsequent preservation of the overlying neurosensory retina (Photodynamic Therapy - PDT)~ radiation therapy ~ and the use of pharmacologic intervention with the advantage of avoiding laser-induced retinal damage~ are all ' options still presently under study with regard to the efficacy in treating AMD~ especially the exudative type. There is no current treatment that restores visual function within areas of geographic atrophy (nonexudative AMD)~ disciform scarring (exudative AMD)~ or photocoagulation (present treatment for CNV).