This document provides information on medically necessary contact lenses including definitions, benefits, insurance plans, eligibility criteria, billing codes, and examples of how to determine diagnoses and appropriate billing for patients. It discusses criteria for medical necessity including conditions like keratoconus, irregular astigmatism, corneal disorders and transplants, and high ammetropia. Examples are provided of patients' exams and determining appropriate diagnoses and billing codes to use for medical insurance and vision plans. Reimbursement rates for different contact lens types and replacement schedules are also included.