Viscocanalostomy and Canaloplasty
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This policy describes coverage criteria for canaloplasty and viscocanalostomy for treatment of glaucoma in commercially insured Blue Cross NC members and explains when these procedures are considered medically necessary, investigational, or not medically necessary.
No material clinical or coverage changes in this revision.
Coverage Criteria
Canaloplasty — Covered with criteria
Canaloplasty may be considered medically necessary when ALL of the following are met:
Viscocanalostomy — Not medically necessary
Canaloplasty — Investigational (other conditions)
Canaloplasty is considered investigational for indications that do not meet the specified medical necessity criteria. This includes use of canaloplasty for angle-closure glaucoma and any other clinical scenarios not explicitly covered by the policy’s medical necessity requirements.
This medical policy is provided for informational purposes only and is not an authorization, certification, explanation of benefits, or a contract. Coverage and payment are determined by the member’s group contract and subscriber certificate in effect at the time services are rendered; providers must verify benefits and eligibility prior to providing services.
Viscocanalostomy is explicitly considered not medically necessary under this policy and therefore is not covered.
Coding
Provider Actions & Requirements
Obtain prior authorization for CPT 66174, 66175
Prior authorization may be required for canaloplasty procedures billed with CPT codes 66174 and 66175; medical records should demonstrate failed medical therapy and that the patient is not a candidate for other IOP‑lowering surgeries.
Confirm benefits and eligibility prior to service
Verify benefits and eligibility with the member's group contract and subscriber certificate before scheduling services; the medical policy document itself does not authorize services.
- Benefits and eligibility are determined by the group contract and subscriber certificate in effect when services are rendered.
Document prior medical therapy failure (step therapy)
Ensure documentation shows prior failure of medical therapy — canaloplasty is considered medically necessary only after medical therapy has failed to adequately control intraocular pressure.
- Failure of medical therapy is a required criterion for medical necessity.
Submit complete medical records upon request
Provide medical records when requested to support medical necessity determinations; include specific information showing prior therapy failure and rationale that the patient is not a candidate for other procedures.
- Letters of support/explanation may be useful but are not sufficient unless all specific information needed to determine medical necessity is included.
- Include justification that the individual is not a candidate for trabeculectomy or glaucoma drainage implant due to high risk for complications.
Medical records must show failed therapy and candidacy rationale
Document both the failed medical therapy and the clinical rationale that the patient is not a candidate for other IOP‑lowering procedures; BCBSNC may request these records to determine medical necessity.
- Show specific IOP control attempts with medications and outcomes.
- Document clinical factors that make other procedures (e.g., trabeculectomy, drainage implant) high risk.
Verify benefits and eligibility under the member's contract
Verify member benefits and eligibility under the applicable group contract and subscriber certificate before relying on the policy; medical policy is informational only and does not constitute authorization.
- Do not assume coverage — confirm with the payer that canaloplasty is covered for the member.
Prior medical therapy failure is required to avoid denial
Canaloplasty will not meet medical necessity criteria if medical therapy has not failed to adequately control intraocular pressure; absence of prior therapy failure may result in denial.
- Ensure records clearly demonstrate inadequate IOP control despite medical therapy before requesting coverage.
Document non‑candidacy for alternative procedures to support coverage
If the patient is a candidate for other IOP‑lowering procedures (e.g., trabeculectomy or glaucoma drainage implant), canaloplasty may not meet the policy criteria and may be denied; document why those procedures are not appropriate due to high risk for complications.
- Provide clinical justification why alternative procedures are contraindicated or pose high complication risk.
Benefits/eligibility verification required before applying policy
Confirm benefits and eligibility prior to services because benefits are determined by the group contract and subscriber certificate; services may be denied if not covered by the member's plan.
- Medical policy is informational and not an authorization, certification, explanation of benefits, or a contract.
Definitions
Background
Glaucoma is a group of progressive optic neuropathies characterized by elevated intraocular pressure (IOP) resulting from impaired aqueous humor outflow through the trabecular meshwork and Schlemm canal. Surgical approaches, including non-penetrating procedures such as viscocanalostomy and canaloplasty, aim to improve outflow and lower IOP when medical therapy is inadequate.
Canaloplasty is an ab externo procedure derived from viscocanalostomy that seeks to dilate and tension Schlemm canal—often with an illuminated microcatheter and suture loop—to enhance physiologic outflow and reduce IOP. These procedures are intended for patients in whom medications have failed to adequately control IOP and who are not candidates for other IOP-lowering surgeries.
Viscocanalostomy is a variant of deep sclerectomy that unroofs and dilates Schlemm canal without entering the anterior chamber, using high-viscosity viscoelastic to open the canal and create a scleral reservoir; it is distinguished from canaloplasty by the absence of a suture tensioning mechanism.
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