Description: A controversial multiple sclerosis drug called Tysabri also reduces vision loss associated with the disease by 47 percent, a new study found. "Vision loss is probably one of the most disabling things that happens to people with MS," said lead researcher Dr. Laura J. Balcer, an associate professor of neurology at the University of Pennsylvania School of Medicine. "The exciting thing is, first, that we now have an eye-chart test that can pick that up and can show if treatments help vision. Second, this particular drug appears to help prevent vision loss."