Today, many patient undergo the combined procedure of cataract extraction (with intraocular lens implantation) and astigmatic keratotomy (AK) to correct astigmatism. However, coding expert Kevin Corcoran points out that correction of pre-existing astigmatism is ineligible for Medicare reimbursement on the grounds that the correction isn't medically necessary.

When performing AK under these conditions, the Medicare Carriers Manual requires you to notify the patient — in writing — that Medicare is unlikely to pay for this service. The patient must understand that he'll be required to cover the cost of the procedure, and must sign the form to indicate acceptance of these conditions.

For this reason, you should provide a physician notice form, or waiver, that advises the patient that this service may not be covered by Medicare. By signing the form, the patient indicates that he has agreed to pay and has elected to proceed.

To indicate that you've complied with the notice requirements, add the modifier "-GA" to procedure code 66999 on the HCFA-1500 claim form.