Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilot© Copyright 2026 American Medical Association. All rights reserved.
The procedure described by CPT® Code 66172 involves the surgical creation of a new drainage pathway for ocular fluids through the sclera, which is the white outer coating of the eyeball. This intervention is specifically indicated for patients suffering from glaucoma, a condition characterized by increased intraocular pressure due to inadequate drainage of aqueous humor, the fluid produced in the front chamber of the eye. In cases where previous ocular surgeries or trauma have resulted in scarring, the trabeculectomy is performed ab externo, meaning from the outside of the eye, to facilitate improved drainage. During this procedure, the surgeon removes a portion of the tissue that connects the iris to the scleral membrane, thereby establishing a new channel for fluid to escape into the space between the sclera and other intraocular structures. Additionally, the procedure includes the injection of antifibrotic agents, which are substances used to prevent excessive scarring and promote the success of the drainage pathway. This code is specifically applicable when the procedure is necessitated by complications arising from prior eye surgeries, highlighting its role in managing glaucoma in patients with a history of ocular interventions.
© Copyright 2026 Coding Ahead. All rights reserved.
The procedure associated with CPT® Code 66172 is indicated for the treatment of glaucoma, particularly in cases where there is a need to address complications arising from previous ocular surgeries or trauma. The following conditions may warrant this procedure:
The procedure for CPT® Code 66172 involves several critical steps to ensure effective drainage of ocular fluids. The following outlines the procedural steps:
After the completion of the procedure, patients are typically monitored for any immediate complications. Post-operative care may include the use of prescribed medications, such as anti-inflammatory or antibiotic eye drops, to promote healing and prevent infection. Patients are advised to follow up with their ophthalmologist to assess the success of the drainage pathway and to monitor intraocular pressure. Recovery time can vary, but patients are generally encouraged to avoid strenuous activities and to adhere to any specific instructions provided by their healthcare provider to ensure optimal healing and outcomes.
| Short Descr | INCISION OF EYE | Medium Descr | FSTLJ SCLERA GLC TRBEC AB EXTERNO SCARRING | Long Descr | Fistulization of sclera for glaucoma; trabeculectomy ab externo with scarring from previous ocular surgery or trauma (includes injection of antifibrotic agents) | Status Code | Active Code | Global Days | 090 - Major Surgery | PC/TC Indicator (26, TC) | 0 - Physician Service Code | Multiple Procedures (51) | 2 - Standard payment adjustment rules for multiple procedures apply. | Bilateral Surgery (50) | 1 - 150% payment adjustment for bilateral procedures applies. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 2 - Payment restriction for assistants at surgery does not apply to this procedure... | Co-Surgeons (62) | 1 - Co-surgeons could be paid, though supporting documentation is required... | Team Surgery (66) | 0 - Team surgeons not permitted for this procedure. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | APC Status Indicator | Hospital Part B services paid through a comprehensive APC | ASC Payment Indicator | Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight. | Type of Service (TOS) | 2 - Surgery | Berenson-Eggers TOS (BETOS) | P1G - Major procedure - Other | MUE | 1 | CCS Clinical Classification | 14 - Glaucoma procedures |
| LT | Left side (used to identify procedures performed on the left side of the body) | RT | Right side (used to identify procedures performed on the right side of the body) | 79 | Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.) | 82 | Assistant surgeon (when qualified resident surgeon not available): the unavailability of a qualified resident surgeon is a prerequisite for use of modifier 82 appended to the usual procedure code number(s). | SG | Ambulatory surgical center (asc) facility service | 51 | Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d). | 80 | Assistant surgeon: surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s). | 52 | Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use). | 54 | Surgical care only: when 1 physician or other qualified health care professional performs a surgical procedure and another provides preoperative and/or postoperative management, surgical services may be identified by adding modifier 54 to the usual procedure number. | 58 | Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78. | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 74 | Discontinued out-patient hospital/ambulatory surgery center (asc) procedure after administration of anesthesia: due to extenuating circumstances or those that threaten the well being of the patient, the physician may terminate a surgical or diagnostic procedure after the administration of anesthesia (local, regional block(s), general) or after the procedure was started (incision made, intubation started, scope inserted, etc). under these circumstances, the procedure started but terminated can be reported by its usual procedure number and the addition of modifier 74. note: the elective cancellation of a service prior to the administration of anesthesia and/or surgical preparation of the patient should not be reported. for physician reporting of a discontinued procedure, see modifier 53. | 78 | Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.) | AQ | Physician providing a service in an unlisted health professional shortage area (hpsa) | AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery | CR | Catastrophe/disaster related | GC | This service has been performed in part by a resident under the direction of a teaching physician | GW | Service not related to the hospice patient's terminal condition | X4 | Episodic/focused services: for reporting services by clinicians who provide focused care on particular types of treatment limited to a defined period and circumstance; the patient has a problem, acute or chronic, that will be treated with surgery, radiation, or some other type of generally time-limited intervention; reporting clinician service examples include but are not limited to, the orthopedic surgeon performing a knee replacement and seeing the patient through the postoperative period |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2011-01-01 | Changed | Guideline information changed. |
| 1994-01-01 | Added | First appearance in code book in 1994. |
Get instant expert-level medical coding assistance.