Refraction is sometimes necessary depending on the patient’s diagnosis and/or complaints presented that day. For example, if a patient is experiencing blurred vision refraction is necessary to determine if there is a need for glasses or if it is due to a medical problem. Also, if it is due to a medical problem, the refraction can be used to aid in tracking the severity of a condition or the progress of recovery. Refraction is also necessary to provide information to insurance companies for cataract surgery. We must prove that your vision cannot be simply improved with a glasses prescription.