Glaucoma Surgical Procedures - (0035)

Coverage Summary

This policy covers surgical procedures and devices used to lower intraocular pressure in glaucoma, including aqueous shunts/aqueous drainage devices (e.g., Ahmed, Baerveldt, ExPRESS, Krupin, Molteno), the XEN 45 Gel Stent, iStent Infinite, and canaloplasty (ab externo or ab interno). It also lists several procedures considered experimental or unproven (e.g., transciliary fistulization, viscocanalostomy/phacoviscocanalostomy and other evolving MIGS not specifically designated as medically necessary).

The intended population is individuals with refractory glaucoma—glaucoma unresponsive to, intolerant of, or with contraindications to conventional medical (topical or oral) and conventional surgical (laser therapy, trabeculectomy) treatments. Coverage stance is mixed: certain devices/procedures (named aqueous shunts, single XEN 45, iStent Infinite, and canaloplasty) are described as medically necessary when policy criteria are met, while other procedures are labeled experimental/investigational/unproven.

Policy administrative dates: Effective 04/15/2026; Last review 04/15/2026; Next review 04/15/2027.

Key facts — devices, codes, XEN, unproven procedures, FDA IDs

Named established aqueous shunt devices listed5

CPT codes listed as medically necessary (device/canaloplasty)3 (66179, 66183, 0449T/0671T and 66174/66175 referenced)

Single XEN 45 Gel Stent allowed1 (XEN 45: CPT 0449T, 66183)

Unproven procedures explicitly listed2 (transciliary fistulization; viscocanalostomy including phacoviscocanalostomy)

FDA‑cleared device identifiers listed (examples)5 (e.g., K161457 XEN; K220032 iStent Infinite; K171905 Visco360; K173332/K202678 OMNI; K041019 Fugo Blade)

Medical Necessity Criteria

Aqueous Shunts/Aqueous Drainage Devices - Medically Necessary

Any of the following aqueous shunts/aqueous drainage devices (CPT Codes 66179, 66183) are considered medically necessary for refractory glaucoma when there is failure, intolerance or contraindication to conventional medical (i.e., topical or oral medication) and surgical (i.e., laser therapy, trabeculectomy) treatment:

Aqueous shunts/aqueous drainage devices

Ahmed glaucoma valve
Baerveldt glaucoma implant
ExPRESS mini glaucoma shunt
Krupin eye valve

Not Medically Necessary / Experimental Procedures

The policy states that coverage in this section is inferred from the evidence and professional statements: some procedures (canaloplasty, viscocanaloplasty/ABiC, OMNI canaloplasty and trabeculotomy ab interno) have conditional support from professional societies but the evidence is limited (primarily retrospective/observational), while other procedures (transciliary fistulization using the Fugo Blade, viscocanalostomy, phacoviscocanalostomy and other evolving interventions) have insufficient peer-reviewed evidence to demonstrate safety and efficacy and are described as not supported for routine coverage.

Device regulatory examples (e.g., Visco360, OMNI Surgical System, Fugo Blade) and their FDA 510(k) clearances are summarized in the policy to provide context about device availability and indications, but the policy emphasizes that device regulatory status is informational/ contextual and not the sole determinant of coverage.

Coding

Medically Necessary - Aqueous Shunts/Aqueous Drainage DevicesCPTCovered

66179	Aqueous shunt to extraocular equatorial plate reservoir, external approach; without graft.
66183	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, external approach.
0449T	Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the subconjunctival space; initial device.
0671T	Insertion of anterior segment aqueous drainage device into the trabecular meshwork, without external reservoir, and without concomitant cataract removal, one or more.

Medically Necessary - CanaloplastyCPTCovered

66174	Transluminal dilation of aqueous outflow canal (eg, canaloplasty); without retention of device or stent.
66175	Transluminal dilation of aqueous outflow canal (eg, canaloplasty); with retention of device or stent.

Considered Experimental/Investigational/UnprovenCPTExperimental

66999

Unlisted procedure, anterior segment of eye (used in policy to represent transciliary fistulization, viscocanalostomy, and other unproven procedures).

FDA device identifiers referencedmixed

K171905	Visco360 Viscosurgical System (Sight Sciences) - 510(k) clearance; product code MRH
K173332	OMNI Surgical System - 510(k) clearance
K202678	OMNI Surgical System - 510(k) clearance
K201953	OMNI PLUS Surgical System - 510(k) clearance
K041019	Fugo Blade for Glaucoma - 510(k) clearance

Provider Actions & Billing Guidance

Documentation Required

Demonstrate failure/intolerance/contraindication to conventional therapy

For devices/procedures deemed medically necessary, clinical documentation must show failure, intolerance, or contraindication to conventional medical (topical or oral) and surgical (laser therapy, trabeculectomy) treatments as applicable.

Topical or oral glaucoma medications
Laser therapy (e.g., trabeculoplasty)
Trabeculectomy

Documentation Required

Document device and procedural approach

When performing canaloplasty/viscocanaloplasty/OMNI procedures document the device used (e.g., OMNI, iTrack, Visco360 where applicable), surgical approach (ab interno vs ab externo), and whether combined with cataract surgery, because device approvals and evidence vary by device and approach.

Background & Evidence Summary

Glaucoma management typically begins with topical or oral medications; for patients unwilling/unable to use medications or unresponsive to medical therapy, laser therapy or trabeculectomy are options. Surgical interventions such as aqueous shunts and microstents are considered for refractory cases where conventional therapies have failed or are contraindicated.

Aqueous shunts (tube implants/drainage devices) are designed to divert aqueous humor to an extraocular reservoir or subconjunctival space; they vary by material, presence of valves/flow restrictors, plate design and may carry risks in addition to those of trabeculectomy (e.g., erosion, diplopia) but have established evidence supporting IOP lowering and long-term follow-up data for first-generation devices.

Canaloplasty and related procedures (viscocanaloplasty/ABiC, OMNI-assisted viscodilation and trabeculotomy) aim to restore physiologic outflow (Schlemm's canal) via microcatheterization and viscodilation, and may be performed standalone or combined with cataract surgery. Evidence includes systematic reviews, randomized trials and observational studies showing IOP reduction, though trabeculectomy generally achieves greater IOP lowering in comparative analyses.

Several devices referenced in the policy received FDA 510(k) clearance (e.g., ExPRESS, XEN Gel Stent, iStent Infinite, Visco360, OMNI, Fugo Blade); the policy notes that inclusion of device names and regulatory identifiers is for example and context and that coverage decisions are not based solely on FDA clearance.

The policy highlights limitations of the evidence base: many MIGS and evolving procedures are supported mainly by retrospective case series, small prospective single-arm studies, or short-term follow-up; randomized controlled trial data are limited for several techniques, and heterogeneity in techniques and patient selection limits generalizability.

Evidence / Source	Key finding
iStent Infinite responder rate (Sarkisian et al. 2022)	76.1% met ≥20% mean diurnal IOP reduction at 12 months in a single-arm study (n=72)
XEN clinical success (Reitsamer et al. 2019)	65.8% clinical success at 24 months in a multicenter case series (n=218 eyes)
Cochrane review (Eldaly et al. 2014)	Limited evidence showed better IOP control with trabeculectomy vs viscocanalostomy
Meta-analysis (Chai & Loon 2010)	Trabeculectomy produced significantly lower mean IOP at 6, 12, 24 months vs viscocanalostomy; viscocanalostomy had higher Descemet membrane perforation risk but lower hypotony and cataract formation
Systematic review / meta-analysis (Zhang et al. 2017; Rulli et al. 2013)	Canaloplasty reduces IOP and meds but is less effective than trabeculectomy for IOP lowering; evidence limited and largely nonrandomized
Professional society assessments (AAO, AGS, ASCRS)	Societies note novel procedures show potential but lack robust randomized trial evidence and recommend continued study/support with conditional endorsement

Definitions

Refractory glaucoma: Glaucoma unresponsive to, intolerant of, or with contraindication to conventional medical and surgical therapies (topical/oral medications, laser therapy, trabeculectomy).

MIGS: Minimally invasive or microinvasive glaucoma surgery; proposed less invasive procedures for mild-to-moderate glaucoma that aim to lower IOP with smaller incisions and an enhanced safety profile compared to traditional incisional surgery.

Viscocanaloplasty / ABiC: Ab interno canaloplasty involving 360-degree viscodilation of Schlemm's canal using a microcatheter and viscoelastic, performed through a clear corneal incision; may be standalone or combined with cataract surgery.

OMNI Surgical System: A handheld ophthalmic surgical tool that delivers controlled amounts of viscoelastic into Schlemm's canal and can cut trabecular meshwork for trabeculotomy (180° or 360°), used for viscodilation and trabeculotomy procedures.

Transciliary fistulization (Fugo Blade): External filtration procedure using the Fugo Blade to create a micropore draining aqueous posterior to the iris into subconjunctival lymphatics; associated with bleb formation and risk of hypotony; FDA-cleared by 510(k) for sclerostomy when maximal therapy and trabeculoplasty have failed.

Revision History

10/15/2024focused_review

Focused review removed policy statements for multiple MIGS devices/procedures including Glaukos iStent, iStent Inject, Ivantis Hydrus, ab interno suprachoroidal microstent, drug-eluting ocular devices, goniotomy/trabeculotomy ab interno, and excimer laser trabeculostomy.

4/15/2024annual_review

Annual review: No clinical policy statement changes.

4/15/2025annual_review

Annual review: No clinical policy statement changes.