>> reporter: r.g.ng like herself again, after months of battling an aggressive eye disease that was only getting worse. >> i was really going sick, double vision all over now, having a really hard time seeing. r.j. is one of the first thyroid eye disease patients to receive the drug tepeza that has just been approved to treat the painful rare condition. thyroid eye disease causes the muscles and fatty tissues behind the eye to become enflamed, forcing the eye to bulge forward. patients can experience headaches, double vision, light sensitivity and lose their sight entirely. >> these muscles get bigger, they start to squeeze the optic nerve. >> reporter: dr. raymond douglas is an ocular surgeon with cedars-sinai medical center. he says the new medication is a game changer in the battle against rare diseases. thyroid eye disease affects up to 20,000 americans every year, it is one of more than 7,000 rare diseases. and no treatments exist for most. with increased awareness, and more research, patients and