Refractive error is a condition in which the image of a distant object is not accurately focused on the retina when parallel light rays from the outside world pass through the refractive system of the eye under relaxed adjustment. Refractive errors include nearsightedness, farsightedness, astigmatism and so on. The causes of refractive error are usually related to genetic factors, environmental factors, congenital maldevelopment of the cornea and/or lens, and bad habits in daily life. Clinical manifestations of refractive errors include myopia (blurred vision at a distance and clearer vision at a near distance), hyperopia (clearer vision at a distance and blurred vision at a near distance), and astigmatism (often characterized by double vision). The examination of refractive error is based on clinical manifestations, fundus examination, visual acuity examination, eye movement and optometry to confirm the diagnosis. The choice of refractive error correction method needs to be decided according to the specific degree of the patient’s condition, and the commonly used ones are frame glasses, corneal contact lenses, and refractive surgery. After refractive error occurs, it is necessary to go to the hospital for examination and treatment in time to avoid delaying the condition.