The Bates method is an ineffective and potentially dangerous alternative therapy aimed at improving eyesight. Eye-care physician William Horatio Bates (1860–1931) held the erroneous belief that the extraocular muscles effected changes in focus and that "mental strain" caused abnormal action of these muscles; hence he believed that relieving such "strain" would cure defective vision. In 1952, optometry professor Elwin Marg wrote of Bates, "Most of his claims and almost all of his theories have been considered false by practically all visual scientists."

No type of training has been shown to change the refractive power of the eye. Moreover, certain aspects of the Bates method can put its followers at risk: They may damage their eyes through overexposure to sunlight, not wear their corrective lenses while driving, or neglect conventional eye care, possibly allowing serious conditions to develop.