CurrentBlue Cross Blue Shield - Rhode IslandPolicy N/A

Viscocanalostomy and Canaloplasty

This policy governs coverage and medical necessity criteria for canaloplasty and viscocanalostomy for treatment of glaucoma for Blue Cross Blue Shield - Rhode Island members.

Policy Summary

PayerBlue Cross Blue Shield - Rhode Island

PolicyViscocanalostomy and Canaloplasty

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateJul 1, 2024

Next Review DateMar 20, 2024

Key ActionVerify member-specific benefits with the provider call center before scheduling; no prior authorization is required per this policy.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

2CPT codes listed for canaloplasty

1Unlisted CPT code specified for viscocanalostomy

Medicare & CommercialCoverage distinctions specified

~16 mmHgReported modest IOP reduction

>=30References and studies cited

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Medical Necessity and Coverage Rules

Medically Necessary Canaloplasty

Canaloplasty may be considered medically necessary when ALL of the following are met:

Criterion 1: Medical therapy has failed to adequately control intraocular pressure

Applies to Medicare Advantage Plans and Commercial Products

Criterion 2: The individual is not a candidate for any other intraocular pressure–lowering procedure (e.g., trabeculectomy or glaucoma drainage implant) due to a high risk for complications

Applies to Medicare Advantage Plans and Commercial Products

Not Covered / Not Medically Necessary

Not covered / Not medically necessary statements:

Medicare Advantage - Not Covered: Canaloplasty is not covered under all other conditions, including angle-closure glaucoma; viscocanalostomy is not covered

Medicare Advantage Plans

Commercial Products - Not Medically Necessary: Canaloplasty is considered not medically necessary under all other conditions, including angle-closure glaucoma; viscocanalostomy is considered not medically necessary

Commercial Products

Coverage excludes procedures performed for angle-closure glaucoma and other conditions not specified in the medically necessary criteria. The policy explicitly states that canaloplasty is not covered/not medically necessary for these out-of-criteria indications, and viscocanalostomy is likewise excluded by plan type. Providers should expect claim denials when canaloplasty or viscocanalostomy is submitted for angle-closure glaucoma or other non‑covered indications.

Viscocanalostomy is specifically identified as not covered/not medically necessary because the available evidence is insufficient to demonstrate a health outcome benefit; this exclusion applies across Medicare Advantage and Commercial product statements in the policy.

Services determined to be not medically necessary or otherwise non‑covered under this policy cannot be billed to the member unless the member was informed in advance and provided written agreement to accept financial responsibility. For member‑specific benefit questions or verification of prior authorization requirements, contact the provider call center. Participation agreements and member/employer benefit documents supersede this policy and govern payment and contractual limits.

For Commercial Products, viscocanalostomy is considered not medically necessary; for Medicare Advantage, viscocanalostomy is not covered. The policy states the reason for this stance is insufficient evidence to determine the effects of the procedure on health outcomes.

Providers should file viscocanalostomy under the unlisted anterior segment procedure code (per coding guidance) but be aware that the procedure is not supported as a covered service by this policy and is therefore subject to denial.

Procedural and Diagnosis Codes

Covered 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

Covered CPT Codes (placeholder for additional systems)mixedCovered

No codes listed

Unlisted / ViscocanalostomyCPTNot Covered

66999

Unlisted procedure, anterior segment of eye (used for viscocanalostomy)

Covered ICD-10-CMICD-10

H40.10X0	Primary open-angle glaucoma, unspecified stage, right eye (example listed as covered ICD-10-CM)
H42	Glaucoma in other diseases classified elsewhere

References and literature (no explicit codes in this section)mixed

No codes listed

IOP reduction target — typical outcome and limitations

Typical postoperative IOPCanaloplasty provides a modest reduction in intraocular pressure, commonly achieving IOP around 16 mm Hg

Limitations for very low IOP goalsMay not lower IOP below the pressure of the distal outflow system (often not <15 mm Hg); therefore not indicated when very low target IOP is required (e.g., advanced glaucoma)

Clinical outcome measuresRelevant outcomes include IOP achieved, reduction in glaucoma medications, need to convert to trabeculectomy, complications, and procedure durability

Billing, Authorization, and Provider Responsibilities

Prior Authorization

Prior Authorization Required

Prior authorization requirement — No prior authorization applicable.

Documentation Required

Verify Member Benefits and Authorization

Verify member benefits and authorization: Contact the provider call center to confirm member-specific benefits, eligibility, and any authorization requirements before scheduling services.

Call provider call center for member-specific benefits and eligibility
Confirm authorization requirements, if any

Documentation Required

Failure of Medical Therapy Required

Failure of medical therapy required: Canaloplasty (CPT 66174, 66175) is considered only when medical therapy has failed to adequately control intraocular pressure and the patient is not a candidate for other IOP‑lowering procedures (e.g., trabeculectomy or glaucoma drainage implant) due to high risk for complications.

Clinical Background

Glaucoma surgery is performed to lower intraocular pressure (IOP) when pharmacologic therapy fails to achieve the target IOP. Procedures that dilate or restore aqueous outflow through Schlemm canal aim to reduce IOP while avoiding bleb‑related complications associated with traditional filtering surgery.

Canaloplasty is an ab‑externo, nonpenetrating approach that circumferentially viscodilates Schlemm canal and places a tensioning suture to improve outflow; viscocanalostomy is a related nonpenetrating sclerectomy technique that dilates Schlemm canal using high‑viscosity viscoelastic. The policy notes these procedures offer an alternative to trabeculectomy but that evidence for viscocanalostomy is insufficient to support coverage.

Procedure Definitions

Viscocanalostomy — definition (non-penetrating with viscoelastic dilation)

DefinitionViscocanalostomy is a non-penetrating variant of sclerectomy that unroofs and dilates Schlemm canal using a high-viscosity viscoelastic (e.g., sodium hyaluronate) without penetrating the trabecular meshwork or anterior chamber to create a passage to a scleral reservoir.

MechanismViscoelastic dilation opens Schlemm canal and creates a scleral reservoir to improve aqueous outflow while avoiding bleb-related complications.

Comparative noteHas been compared with trabeculectomy in randomized trials; generally yields less IOP lowering than trabeculectomy in meta-analyses.

Canaloplasty — ab externo with illuminated microcatheter and tensioning suture

DefinitionCanaloplasty is an ab externo procedure using an illuminated microcatheter (eg, iTrack) to catheterize and viscodilate Schlemm canal and to pass a tensioning suture through the canal.