CurrentKaiser PermanentePolicy N/A

Clinical Review Criteria — Glaucoma Surgical Procedures (Canaloplasty and MIGS)

Clinical review criteria governing coverage and medical necessity for canaloplasty and microinvasive glaucoma surgery (MIGS) devices for Kaiser Permanente Washington members; distinguishes rules for Medicare and non‑Medicare members and lists required documentation and applicable CPT/HCPCS codes.

Policy Summary

PayerKaiser Permanente

PolicyClinical Review Criteria — Glaucoma Surgical Procedures (Canaloplasty and MIGS)

Policy CodePolicy N/A

Change TypeNo material change

Effective DateAug 1, 2020

Next Review DateN/A

Key ActionObtain prior authorization/medical necessity review for listed canaloplasty and MIGS codes for non‑Medicare members and submit last 6 months of clinical notes to support the request.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

2procedure categories

>=18min age (MIGS)

6 modocumentation lookback

3non-covered codes

08/05/2025last review

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Coverage and Medical Necessity Criteria

MIGS — iStent Device and Hydrus

iStent Device and Hydrus will be considered medically necessary when ALL of the following are met:

ALL of the following

Procedure is performed only in conjunction with cataract surgery (phacoemulsification with intraocular lens implantation).
The individual is currently being treated with an ocular hypotensive medication and/or had prior laser trabeculoplasty.
Used to reduce intraocular pressure (IOP) > 21 mm Hg, except when clinical circumstances support a lower IOP (this rationale should be documented in the medical record).
Patient is 18 years of age or older.
Diagnosis of mild to moderate primary open-angle glaucoma (POAG) as documented by clinical assessment and visual field testing consistent with mild to moderate disease).
- Prior significant ocular trauma.
- Abnormal anterior segment anatomy.
- Chronic ocular inflammation.
- Glaucoma associated with vascular disorders.
- Pseudophakic patients with glaucoma (i.e., prior cataract surgery without concurrent implantation).
- Uveitic glaucoma.
- Eyes with prior incisional glaucoma surgery or cilioablative procedures.

MIGS — Contraindications

Contraindications / exclusions for MIGS (iStent/Hydrus):

ANY of the following

Angle-closure glaucoma.
Traumatic, malignant, uveitic, or neovascular glaucoma, or discernible congenital anomalies of the anterior chamber angle.
Patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber syndrome, or other conditions that may cause elevated episcleral venous pressure.

Applicable CPT/HCPCS Codes and Clinical Thresholds

Canaloplasty CPT CodesCPTCovered

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

MIGS / Aqueous drainage device codes — considered medically necessary when criteria metmixedCovered

0449T	Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the subconjunctival space; initial device.
66183	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, external approach
66989	Extracapsular cataract removal with insertion of intraocular lens prosthesis (complex) with insertion of intraocular anterior segment aqueous drainage device, internal approach
66991	Extracapsular cataract removal with insertion of intraocular lens prosthesis; with insertion of intraocular anterior segment aqueous drainage device, internal approach

Not medically necessary codesCPTNot Covered

0253T	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, internal approach, into the suprachoroidal space.
0671T	Insertion of anterior segment aqueous drainage device into the trabecular meshwork, without external reservoir, and without concomitant cataract removal, one or more

Considered medically necessary when criteria metCPTCovered

0449T	Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the subconjunctival space; initial device.
66183	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, external approach
66989	Extracapsular cataract removal with insertion of intraocular lens prosthesis (1-stage procedure), complex; with insertion of intraocular anterior segment aqueous drainage device, without extraocular reservoir, internal approach, one or more.
66991	Extracapsular cataract removal with insertion of intraocular lens prosthesis (1-stage procedure); with insertion of intraocular anterior segment aqueous drainage device, without extraocular reservoir, internal approach, one or more.

Considered not medically necessaryCPTNot Covered

0253T	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, internal approach, into the suprachoroidal space.
0671T	Insertion of anterior segment aqueous drainage device into the trabecular meshwork, without external reservoir, and without concomitant cataract removal, one or more

Cypass (no longer available) - Not medically necessaryCPTNot Covered

0474T

Insertion of anterior segment aqueous drainage device, with creation of intraocular reservoir, internal approach, into the supraciliary space (Cypass — no longer available).

Intraocular pressure (IOP) threshold for MIGS candidacy (inv-15)

IOP threshold> 21 mmHg for MIGS candidacy unless a lower target IOP is clinically justified and documented

Documentation requirementWhen a lower than 21 mmHg target is used, the clinical rationale must be documented in the medical record

Applicable devicesiStent and Hydrus (used only in conjunction with cataract surgery per policy)

Refractory glaucoma definition for XEN (inv-16)

Refractory glaucoma definitionProgressive damage with mean diurnal medicated IOP ≥20 mm Hg on maximally tolerated medical therapy

Authorization, Documentation, and Denial Guidance

Prior Authorization

Prior Authorization and Medicare Note

Prior authorization or medical necessity review is required for non‑Medicare members for certain glaucoma procedures. Medicare members are handled per Medicare rules and may not require prior authorization through this plan.

Applicable to non‑Medicare members: prior authorization/medical necessity review required.
Medicare members: medical necessity review not required via this policy; follow Medicare rules.

Prior Authorization

Authorization Requirement by Code

Verify whether a specific CPT/HCPCS code requires pre‑authorization for the member's plan prior to scheduling or billing.

Use the Pre‑authorization Code Check to verify authorization requirements for a specific code by plan type.
Codes and plan rules differ by member type (e.g., commercial vs. Medicare).

Clinical Background

Background: Glaucoma is an optic neuropathy typically associated with elevated intraocular pressure (IOP) that can produce progressive visual field loss. Initial management is medical therapy with topical IOP-lowering medications and laser trabeculoplasty; surgical options are considered when IOP is not controlled on maximally tolerated therapy. Canaloplasty and microinvasive glaucoma surgery (MIGS) are less invasive surgical approaches intended to restore or augment aqueous outflow and potentially reduce medication burden compared with more invasive filtration surgeries.

Definitions

MIGS — Microinvasive glaucoma surgery definition and characteristics (inv-26)

DefinitionMicroinvasive (minimally invasive) glaucoma surgery (MIGS) are ab interno procedures performed via gonioscopic guidance that involve minimal tissue trauma to lower IOP and reduce medication burden

Typical approachMost MIGS use an internal (ab interno) approach and can be performed concomitantly with cataract surgery

Intended benefitsFaster recovery and fewer severe complications compared with traditional filtration surgery; may preserve options for future trabeculectomy

Examples of FDA‑cleared devicesiStent, CyPass (removed from market), and XEN (device types differ by outflow pathway)

Canaloplasty — definition (inv-27)

DefinitionCanaloplasty is a nonpenetrating procedure using viscodilation and 360° catheterization with placement of a tensioning suture in Schlemm's canal to increase trabeculocanalicular outflow without creating a bleb

Policy Revision History

2025-08-05policy_reviewLatest

Last reviewed by MPC (medical policy committee).

2024-08-06administrative_update

Document version note shows prior MPC activity on 08/06/2024 (administrative revision dates listed).

2023-11-13link_update

Policy Summary

PayerKaiser Permanente

PolicyClinical Review Criteria — Glaucoma Surgical Procedures (Canaloplasty and MIGS)

Policy CodePolicy N/A

Change TypeNo material change

Effective DateAug 1, 2020

Next Review DateN/A

Key ActionObtain prior authorization/medical necessity review for listed canaloplasty and MIGS codes for non‑Medicare members and submit last 6 months of clinical notes to support the request.

SourceLink

On This Page

Eyes with prior laser trabeculoplasty (LT) with selective LT within 90 days prior to screening or prior argon laser trabeculoplasty (ALT) at any time.

Patients with unmedicated IOP > 36 mm Hg after washout of medications.

Plan for implantation of more than two stents.

Eyes with complications during the concurrent cataract surgery (eg, severe corneal burn, need for vitrectomy, corneal injuries requiring anterior chamber IOL).

When implantation is performed without concomitant cataract extraction with IOL implantation for visually significant cataract.

Maximally tolerated therapyDefined as ≥4 classes of topical IOP‑lowering medications, or fewer if intolerance/efficacy issues documented

Alternate XEN indicationsAlso considered for previous surgical treatment failure, primary open‑angle glaucoma, or pseudo‑exfoliative/pigmentary glaucoma unresponsive to maximal therapy

Denial Risk

Failure to Meet Medical Necessity Criteria

Procedures may be denied for non‑Medicare members if medical necessity criteria are not met. Ensure documented evidence meets all applicable policy criteria before requesting authorization.

Example: Canaloplasty — covered only when all listed criteria are met (e.g., inadequate IOP control on maximally tolerated topical medications and prior laser treatment when applicable).
Example: MIGS (iStent/Hydrus) — must meet all enumerated inclusion/exclusion criteria (e.g., used only with cataract surgery, IOP criteria, age, glaucoma severity, and absence of listed exclusions).
Failure to document required prerequisites (medication/laser history, contraindications, etc.) may result in denial.

Billing Rule

Coding Validity

Deleted codes and codes not in effect at the time of service may not be covered. Confirm code validity for the date of service.

Policy note: Deleted codes and codes not in effect at time of service may not be covered.
Review code history and effective dates prior to claim submission.

Documentation Required

Medication and Prior Treatment Prerequisites

Before requesting authorization, document that the patient has inadequate intraocular pressure control on maximally tolerated topical medications and any required prior treatments (for example, prior laser trabeculoplasty when applicable).

Canaloplasty prerequisite: inadequate control on maximally tolerated topical medications and prior laser treatment when applicable.
MIGS prerequisite: currently being treated with ocular hypotensive medication and/or had prior laser trabeculoplasty as specified in the criteria.

Documentation Required

Required Clinical Documentation

Submit supporting clinical documentation with authorization requests to avoid delays or denials.

Provide the last 6 months of clinical notes from the requesting provider and/or specialist.
Include documentation of medication history, prior laser procedures, relevant exam findings, and rationale when clinical circumstances justify deviation from standard numeric thresholds (e.g., target IOP).
Attach operative reports and prior surgery records when prior incisional procedures are part of the exclusion/inclusion assessment.

Technique detailsProcedure performed under a scleral flap; catheter with illuminated tip intubates full length of Schlemm's canal and viscoelastic is used for dilation; a suture is left to tension the canal

Contraindications/limitationsNot suitable when 360° catheterization is prevented (e.g., prior surgery with canal scarring), or in angle recession/neovascular or chronic angle‑closure glaucoma

Anterior segment aqueous drainage device — definition and examples (inv-28)

DefinitionAnterior segment aqueous drainage device: a surgically implanted device placed via internal or external approaches to facilitate aqueous humor drainage

Approach typesDevices may be inserted via internal (ab interno) or external approaches and may target trabecular meshwork, supraciliary/suprachoroidal, or subconjunctival pathways

Examples and coding referencesExamples include trabecular bypass stents (iStent), suprachoroidal stents (CyPass — removed from market), and subconjunctival shunts (XEN45); CPT/HCPCS codes cited: 0449T, 66183, 66989, 66991

Updated Medicare coverage article link (A57864).

2022-01-27coding_update

Updated applicable coding (removed deleted codes 0191T, 0376T; added codes 66989, 66991; referenced 0671T).

2020-08-01effective_date

New coverage criteria for Xen Gel & iStent/Hydrus were adopted and became effective on this date.

2019-08-06mtac_review

MTAC review for XEN Gel was added to the record.

2018-11-14content_change

Language regarding iStent was added to the policy.

2018-10-08content_change

Non-coverage language for the Cypass device was added.

2018-06-05policy_approval

MPC approved criteria for commercial members.

2018-02-06creation

Policy created (initial documentation entry dated 02/06/2018).