Medicare Reimbursement for iStent Trabecular Micro-Bypass Stent (Glaukos)



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Q  What is the iStent® trabecular micro-bypass system?

iStent® is a small (1 mm X 0.33 mm) device designed to fit into Schlemm’s canal to facilitate aqueous drainage from the anterior chamber.  It is made of non-magnetic, surgical grade titanium; it is coated with heparin and comes preloaded in an inserter.  There are two different orientations of iStent – one for each eye.1.


Q  What are the indications for iStent?

A  As approved by the FDA in June 2015, the iStent “…is indicated for use in conjunction with cataract surgery for the reduction of intraocular pressure (IOP) in adult patients with mild or moderate open-angle glaucoma currently treated with ocular hypotensive medication.”2.


Q  Is iStent indicated for patients with glaucoma in the absence of cataract?

A  No.  The FDA approval specifies “in combination with cataract surgery”.  All other uses are “off-label” and experimental or investigational.  As a general rule, third party payers do not cover experimental and investigational procedures.


Q  What CPT code describes implantation of iStent?

A  A Category III CPT code, 0191T, applies.  It reads, “Insertion of anterior segment aqueous drainage device, without extraocular reservoir; internal approach, into the trabecular meshwork.”

Effective January 1, 2015, a second Category III code, +0376T, applies when an additional iStent is implanted in the same session.  This code is defined as, “Insertion of anterior segment aqueous drainage device, without extraocular reservoir; internal approach, into the trabecular meshwork; each additional device insertion (list separately in addition to code for primary procedure).”  This add-on code is only used in conjunction with 0191T.


Q  Does Medicare cover this procedure?

A  Yes, all Medicare Administrative Contractors (MACs) cover this procedure when medically necessary.  Check your local MAC for specific reimbursement information.


Q  Do commercial payers cover the iStent procedure?

A  Yes, many commercial payers3 cover the iStent.  Prior authorization should be obtained before scheduling a procedure whenever possible.


Q  What is the global period for 0191T?

A  As a Category III code, there is no specified global period for 0191T.  The global period for concurrent cataract surgery is 90 days.  As a practical matter, the known interval outweighs the unknown interval.


Q  What does Medicare allow for 0191T?

A  Payment rates vary by type of provider and site of service.  In 2019, the Medicare allowed amounts for 0191T are:

  • Physician ………………… MAC discretion
  • ASC Facility Fee …………….. $2,679.62
  • HOPD Facility Fee ……………$3,640.26

Because the known values are higher than the allowed amounts for the concurrent cataract surgery, 0191T ought to be the primary procedure.  These amounts are adjusted in each locality by local wage indices and are additionally subject to payer restrictions which can vary considerably.

For the add-on code, +0376T, there is likewise no set payment rate for physician services.  For ASCs and HOPDs, +0376T is bundled with the primary procedure using status indicators N1 and N respectively.


Q  May gonioscopy be billed at the time of iStent implantation?

A  No.  Gonioscopy (CPT 92020) is required to implant the iStent.  Because gonioscopy carries the “separate procedure” designation in CPT, it should not be billed when it is integral to the performance of another procedure.


Q  Is there separate Medicare reimbursement for the iStent device?

A  No. Medicare payment for the iStent is included in the facility reimbursement for APC 5492. On UB-04 claims, use HCPCS code C17834 and revenue code 278, together with 0191T, to report the iStent procedure. If another iStent is used in the same operation, then include another line on the UB-04 for +0376T, again with C1783 and revenue code 278. On the CMS-1500 form for ASCs, show 0191T and +0376T. The beneficiary may not be charged for the iStent device(s) since it is included in the facility fee. For other payers, check your contracts with respect to prosthetic devices.


Q  How should we bill if one surgeon removes the cataract and another implants the iStent?

A  If both surgeons are part of the same group, then only a single claim is needed and the aggregate payment is made to the group.  When the surgeons are not part of the same group, then separate claims are required.


Q  Are there any NCCI edits or bundles for CPT 0191T?

A  Yes; NCCI edits include paracentesis and anterior chamber injections, as well as others. In addition, all edits in place for the concurrent cataract procedure pertain. Check NCCI edits periodically as they change quarterly. Most third party payers follow NCCI edits, but not all; check your payer contracts.


1.  Glaukos (Manufacturer) website.  Link here.

2.  iStent Directions for Use.  Link here.

3.  Favorable payers include Aetna, Cigna, UHC and most Blue Cross/Blue Shield plans

4. CMS requires HOPDs to report HCPCS code C1783 on claims for Medicare, although it does not garner additional payment. Other payers may accept the code on a UB-04 claim for ASCs.


Provided Courtesy of Glaukos Corporation  (800) 452-8567


Last updated April 9, 2019


The reimbursement information is provided by Corcoran Consulting Group based on publicly available information from CMS, the AMA, etc. The reader is strongly encouraged to review federal and state laws, regulations, code sets, and official instructions  promulgated by Medicare and other payers. This document is not an official source nor is it a complete guide on reimbursement. Although we believe this information is accurate at the time of publication, the reader is reminded that this information, including references and hyperlinks, changes over time, and may be incorrect at any time following publication.

© 2019 Corcoran Consulting Group.   All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a retrieval system, without the written permission of the publisher. CPT is a registered trademark of the American Medical Association.

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