clipped from: www.nytimes.com   
For almost a century, eye exercises have been promoted as a way to strengthen vision and ease nearsightedness and astigmatism, much like exercise for the body trims fat and improves health.
But several studies have concluded that many of these do-it-yourself techniques are baseless.

But there are some areas of vision therapy that have been scientifically validated, including one called orthoptics. In this therapy, eye doctors prescribe exercises that can relieve double vision, focus problems and conditions like strabismus, also known as crossed eyes. Orthoptics can treat convergence insufficiency, in which the eyes have trouble working together. It affects as many as 1 in 5 people, but with the right exercises it can be all but cured, studies show.