Yes, there has been work done on that in the U.S. We have material that we will leave with you that includes indications from the Framingham study, a longitudinal study on health outcomes for people. I think there were 4,000 or 5,000 people in the study over a long period of time. The shocking figure from the study was that over 2004-05, the cost to the U.S. health system for falls and injuries related to vision loss was $2.2 billion.
Again, we don't have the research to say that if we teach people how to use a white cane, if we teach people how to keep their balance even though they no longer have a horizon as a frame of reference, we can prevent all the injuries and falls of somebody with vision loss, because generally we're also talking about somebody who has such other issues as mobility, arthritis, and that sort of thing. However, we can be pretty certain and confident, I think, that if those people were receiving orientation and mobility training--that is, how to move without sight, how to move with a white cane, how to orientate yourself in space without visual references--we could reduce a fair proportion of those falls that are vision related.