Question: Nebraska Subscriber Answer: The ABN is voluntary for items that are statutorily excluded (never covered by Medicare, such as refraction) or do not meet the definition of a Medicare benefit. A patient undergoing a keratonocus workup or contact lens fitting needs to sign an ABN from Medicare informing him that he is responsible for the payment, although it may already appear redundant. The ABN is a waiver signed by the patient to clarify that he needs to pay for the service. The patient's signature on the document is important because it is assumed that once he signs it he has read and understands it and thus he can be held financially liable for the services. . In the case of refraction for the purpose of keratoconus workup or contact lens fitting, there have been debates if the ABN is still necessary since, some argue, that you can simply tell the patient that Medicare doesn't cover the procedure. However: According to CMS, the situations that call for an ophthalmologist's patient to sign an ABN should remain the same when using the new form. "The ABN is only issued when the provider has an expectation of noncoverage," CMS states.