The vision of patients after cataract surgery usually improves rapidly to normal, rather than gradually. Cataracts are a common ophthalmic condition that occurs in the elderly and is usually caused by aging factors that lead to degeneration of the lens inside the eye and a decrease in transparency. Patients experience a painless and progressive loss of vision, which can last up to several years. Treatment usually involves surgery to replace the diseased lens with a clear IOL to restore vision. After the surgery, the factors that blocked the refraction of light from the patient’s eye disappear, so vision improves rapidly to normal, rather than gradually.