Who told you that scars should not exceed 5 cm? There is no regulation on scar size in the Standard for Physical Examination and Appraisal of Civil Aviation Recruitment. If skull surgery is performed, even if the scar is only 1 and 2 cm, it is not qualified. Myopia correction surgery is unqualified because there is no scar on the surface. Scar mainly depends on the nature and causes of formation. Not only the area, but also the depth. Whether it crosses the joint, whether the local function is normal, whether it seriously affects the appearance and other factors.