Prescribing Spectacles

Vision is a collective process of optics, physiology, and visual perception at the higher centers of the brain. To achieve clear vision, all these processes must be intact. Imperfect optics, resulting in refractive error, can be alleviated through a pair of spectacles. However, all the processes that contribute collectively toward vision also determine the final spectacle prescription for a patient. As a result of this complex interplay and physiological variabilities, the same patient examined by the same examiner may end up with different spectacle prescriptions on two separate occasions. This variability must be kept in mind, especially while changing earlier spectacles. Determining a spectacle prescription is a collaborative effort, involving both the examiner and the patient. Truly, prescribing a pair of spectacles is both an art and a science. Science is learned, and art comes with practice. This chapter aims to give tips on both science and craft.