William Horatio Bates (December 23, 1860 – July 10, 1931) was an American physician who practiced ophthalmology and developed what became known as the Bates Method for better eyesight, an educational method intended to improve vision by undoing a supposed habitual strain to see. The efficacy of the method is questionable, and his theory that the eye does not focus by changing the power of the lens, but rather by elongating the eyeball, through use of the extraocular oblique muscles, was contradicted by mainstream ophthalmology and optometry of his day and still is today.