Skip to main content
  • IRIS39: Glaucoma – Intraocular Pressure Reduction Following Trabeculectomy or an Aqueous Shunt Procedure

    Updated April 2023. Changes for 2023 indicated in red.

    The measure is approved for traditional MIPS submission pathway only.

    Care Setting: Ambulatory Care: Clinician Office/Clinic

    Reporting Options: 

    • IRIS Registry QCDR for EHR: groups and individuals
    • IRIS Registry QCDR manual data entry: groups and individuals

    Measure Type: Outcome

    NQS Domain: Effective Clinical Care

    Meaningful Measure Area: Management of Chronic Conditions

    Description:  Percentage of patients who underwent trabeculectomy or aqueous shunt procedures who had IOP reduced by 20% or more from their pretreatment between 3 and 4 months of treatment or a reduction in overall number of glaucoma medications.

    Risk Adjusted: No
    Performance Rate: 1
    High Priority Measure: Yes
    Inverse Measure: No 
    Proportional Measure

    To Which Patients Does the Measure Apply?

    Denominator: Patients aged between 40 and 85 years with a diagnosis of open-angle glaucoma, pigmentary glaucoma, primary open-angle glaucoma, pseudoexfoliation glaucoma or chronic angle glaucoma and who underwent a trabeculectomy or an aqueous shunt procedure.

    There are three criteria for inclusion of a patient into the denominator.

    1. Patient characteristics: Description located in “Denominator” (see above).
    2. Diagnosis codes (ICD-10-CM): Codes located in “Diagnosis Codes.”
    3. Procedure codes (CPT): Codes located in “CPT Codes.” 

    The quality measure also has exclusions for the denominator.

    Diagnosis Codes

    Diagnosis of glaucoma with documentation of severity

    • Open-angle glaucoma, unspecified (ICD-10: H40.10X1, H40.10X2, H40.10X3)
    • Low-tension glaucoma (ICD-10: H40.1211, H40.1212, H40.1213, H40.1221, H40.1222, H40.1223, H40.1231, H40.1232, H40.1233)
    • Pigmentary glaucoma (ICD-10: H40.1311, H40.1312, H40.1313, H40.1321, H40.1322, H40.1323, H40.1331, H40.1332, H40.1333, H40.1391, H40.1392, H40.1393)
    • Primary open angle glaucoma (ICD-10: H40.1111, H40.1112, H40.1113, H40.1121, H40.1122, H40.1123, H40.1131, H40.1132, H40.1133)
    • Pseudoexfoliation glaucoma (ICD-10: H40.1411, H40.1412, H40.1413, H40.1421, H40.1422, H40.1423, H40.1431, H40.1432, H40.1433, H40.1491, H40.1492, H40.1493)
    • Chronic angle glaucoma (ICD-10: H40.2211, H40.2212, H40.2213, H40.2221, H40.2222, H40.2223, H40.2231, H40.2232, H40.2233, H40.2311, H40.2312, H40.2313, H40.2321, H40.2322, H40.2323, H40.2331, H40.2332, H40.2333, H40.2411, H40.2412, H40.2413, H40.2421, H40.2422, H40.2423, H40.2431, H40.2432, H40.2433)

    CPT Codes

    • Trabeculectomy procedure (CPT: 66170, 66172 with modifier RT, LT, -50)


    • Aqueous shunt procedure (CPT: 66179, 66180, 66183, 0449T with modifier RT, LT, -50, 0450T with modifier RT, LT, -50)

    How to Report the Measure

    Numerator: Patients with a reduction in IOP ≥ 20% from the pretreatment level or a reduction in the overall number of glaucoma medications. The procedure must be performed during the performance year.

    Numerator Calculation

    % change between pretreatment IOP (Do not include IOP values taken on the day of procedure) and the lowest IOP measures between 3 and 4 months postoperatively OR a reduction in the overall number of glaucoma medications

    Calculation is based on the IOP of the eye that underwent the procedure.  Medications are by patient, if it cannot be identified by eye level

    Denominator Exclusions

    • Eyes with absolute glaucoma blindness (ICD-10: H44.511, H44.512, H44.513)
    • Visual acuity findings: Count fingers (CF or FC), Hand motion (HM), Light perception (LP), No light perception (NLP)

    How CMS Scores Your Performance

    See the QPP resource library for benchmarks.


    This measure has been developed by the H. Dunbar Hoskins Jr. MD Center for Quality Eye Care of the American Academy of Ophthalmology. The measure is not a clinical guideline and does not establish a medical standard. It has not been tested in all possible applications.

    The measure, while copyrighted, can be reproduced and distributed with appropriate credit, without modification, for noncommercial purposes, e.g., use by health care providers in connection with their practices. The American Academy of Ophthalmology encourages use of the measure by other health care professionals, where applicable.

    Commercial use is defined as the sale, license or distribution of the measures for commercial gain, or incorporation of some or all of a measure into a product or service that is sold, licensed or distributed for commercial gain. Commercial uses of the measures require a license agreement between the user and the American Academy of Ophthalmology. Neither the Academy nor its members shall be responsible for any use of the measures. 


    © 2018-2023 American Academy of Ophthalmology. All rights reserved. Limited proprietary coding from Current Procedural Terminology (CPT®) is contained in the measure specifications. Users of this code set should obtain all necessary licenses. The Academy disclaims all liability for use or accuracy of the coding contained in these measure specifications. CPT® contained in the measures specifications is copyright 2023 American Medical Association.