Associated Press The Food and Drug Administration yesterday approved a new drug designed to treat the leading cause of blindness in older Americans. Age-related macular degeneration destroys the light-sensitive tissue in the center of the retina, causing vision to fail gradually from the center outward. The new drug, Macugen, attacks the rapidly progressing "wet" type of AMD, in which new blood vessels form behind the retina and then leak, damaging the macula. That form affects an estimated 1.6 million Americans over 50, and about 6.3 million are expected to be affected by 2030 as the baby boomers age. Macugen inhibits...