Stents and shunts for glaucoma
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This policy governs coverage determinations for implantation of ab interno microstents and ab externo aqueous shunts for treatment of glaucoma for Medicare Advantage and commercial members of Blue Cross Blue Shield - Rhode Island.
No material clinical or coverage changes in this revision.
Coverage Criteria
Medically necessary indications
Covered when ALL of the following are met for specified device types:
Applies to Medicare Advantage Plans and Commercial Products; device examples include Ahmed and Baerveldt.
Applies to Medicare Advantage Plans and Commercial Products; evidence includes comparative and single-arm studies showing reductions in IOP and medication use.
Supported by randomized trials and meta-analyses demonstrating modest but significant IOP and medication reductions through 2 years.
Not covered / Not medically necessary indications
Not covered / Not medically necessary when ANY of the following apply:
Evidence is insufficient to determine effects on health outcomes for these other indications.
Evidence is insufficient to determine effects on health outcomes for these other indications.
Randomized trial evidence is heterogeneous with limited long-term durability data (most published follow-up at 12 months).
Coverage with criteria
Coverage is conditional and evidence-based; see criteria and coding requirements below.
Claims for the listed CPT/Category III codes must include an appropriate ICD-10 diagnosis to support medical necessity; see coding section for allowed procedure codes.
This policy addresses the use of ab interno microstents and ab externo aqueous shunts for treatment of glaucoma. Coverage determinations differentiate FDA‑approved uses (for example, ab externo shunts for refractory glaucoma and ab interno stents when medical therapy has failed or when placed with cataract surgery) from other, off‑label or unsupported indications. Providers should follow the specific criteria and coding requirements in the policy: procedures using the listed aqueous drainage device codes are covered only when billed with a supporting ICD‑10 glaucoma diagnosis (H40.10X0 - H42) and when the clinical indication aligns with the covered scenarios described below.
The evidence is insufficient to support stand‑alone implantation of aqueous microstents in patients with mild‑to‑moderate open‑angle glaucoma who are not undergoing cataract surgery. Randomized trials show IOP reduction at 12 months in some studies, but limited follow‑up, heterogeneous comparators, and uncertain long‑term durability preclude a determination that stand‑alone microstents improve net health outcomes.
Use of ab externo aqueous shunts or ab interno stents for indications other than those specified (for example, implantation when intraocular pressure is adequately controlled with medications) is considered not covered for Medicare Advantage Plans and not medically necessary for Commercial Products because the evidence does not support benefit in these other indications.
Randomized controlled trials of stand‑alone microstents provide mixed results: some trials demonstrate IOP reduction at 12 months comparable to medical therapy, while others show differences between devices or numbers of stents. Key limitations include 12‑month typical follow‑up, heterogeneous comparators, and lack of corroboration or longer‑term durability data; consequently, the evidence remains insufficient to conclude a net health benefit for many standalone microstent applications.
Coding
| No codes listed |
| 66179 | Aqueous shunt to extraocular equatorial plate reservoir, external approach; without graft |
| 66180 | Aqueous shunt to extraocular equatorial plate reservoir, external approach; with graft |
| 66183 | Insertion of anterior segment aqueous drainage device, without extraocular reservoir; external approach |
| 66184 | Revision of aqueous shunt to extraocular equatorial plate reservoir; without graft |
| 66185 | Revision of aqueous shunt to extraocular equatorial plate reservoir; without graft |
| 66989 | Extracapsular cataract removal with insertion of intraocular lens prosthesis, complex; with insertion of anterior segment aqueous drainage device, internal approach, one or more |
| 66991 | Extracapsular cataract removal with insertion of intraocular lens prosthesis; with insertion of anterior segment aqueous drainage device, internal approach, one or more |
| 0253T | Insertion of anterior segment aqueous drainage device, without extraocular reservoir; internal approach, into the suprachoroidal space |
| 0449T | Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the subconjunctival space; initial device |
| 0450T | Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the subconjunctival space; each additional device |
| H40.10X0 - H42 | ICD-10 Diagnosis Codes that may support medical necessity (glaucoma codes range) |
Provider Actions & Authorization
Prior authorization — policy states “Not applicable”; verify contract variations
Prior Authorization: Not applicable per this policy, but benefits may vary by contract — verify member-specific requirements in the Benefit Booklet, Evidence of Coverage, or Subscriber Agreement before scheduling procedures.
- Policy lists “Not applicable” for Prior Authorization.
- Benefits may vary between groups/contracts; verify member’s plan documents.
Authorize/bill procedures only with a covered ICD-10 glaucoma diagnosis
The CPT and Category III procedure codes listed in the policy are covered only when billed with a supported ICD-10 diagnosis in the H40.10X0–H42 range; providers should ensure coding reflects a covered glaucoma diagnosis before billing or requesting authorization.
Sequence therapy: proceed to stent/shunt only after medical therapy fails to achieve target IOP
Surgical treatment (ab externo shunts or ab interno stents) is indicated when target intraocular pressure cannot be reached with pharmacologic therapy; microstents and shunts are considered when medical therapy has failed to adequately control IOP.
- First-line therapy is pharmacologic; surgery is indicated when target IOP cannot be reached pharmacologically.
- Policy states insertion of ab externo shunts and ab interno stents is medically necessary when medical therapy has failed to adequately control IOP.
Clinical context: RCT comparators were topical medications (implies prior/ongoing medical therapy)
Randomized trials in the policy compared microstents with topical ocular medications (medical therapy comparators), indicating that prior use of medical therapy was part of trial comparators and is a relevant clinical context when considering implantation.
- Several RCTs compared microstents to ocular medications and found similar IOP reduction at 12 months.
- Clinical trials’ comparators imply prior or concurrent medical therapy use in the evidence base.
Benefit verification required — check member plan documents
Verify member benefits and coverage rules before scheduling: benefits for these procedures may vary by group/contract — consult the member’s Benefit Booklet, Evidence of Coverage, or Subscriber Agreement.
- Benefit verification is required because coverage may differ between groups/contracts.
- Reference the appropriate plan documents for applicable surgery and not covered/not medically necessary benefits.
Include supporting ICD-10 diagnosis (H40.10X0–H42) on claims for insertion/revision codes
Claims for insertion or revision of aqueous drainage device codes must include an appropriate ICD-10 diagnosis code from the H40.10X0–H42 range to support medical necessity.
- Policy explicitly states the listed codes are covered only when used for a covered ICD-10 diagnosis code.
- Ensure claims include an ICD-10 in H40.10X0–H42.
Denial risk: procedures for non‑specified indications (including when IOP is controlled) may be denied
Use of ab externo aqueous shunts or ab interno stents for indications outside the policy’s specified indications (for example, when IOP is adequately controlled by medications or other non‑approved indications) is considered not covered/not medically necessary and may be denied.
- Policy states use for other conditions — including when IOP is adequately controlled by medications — is not covered for Medicare Advantage and considered not medically necessary for Commercial Products.
- Billing for disallowed indications may trigger claim denial.
Coverage contingent on supported ICD-10 diagnosis for listed procedure codes
Coverage for the listed CPT/Category III procedure codes is contingent on being billed with a supported ICD-10 diagnosis (H40.10X0–H42); absence of a covered diagnosis on the claim may trigger denial.
- The policy lists specific procedure codes that are covered only when used for a covered ICD-10 diagnosis.
- Verify diagnosis coding falls within H40.10X0–H42 before billing or authorizing the procedure.
Background
Glaucoma is a progressive optic neuropathy often associated with elevated intraocular pressure (IOP) leading to visual field loss. First‑line therapy typically consists of topical pharmacologic agents to lower IOP. When target IOP cannot be achieved or maintained with medications, surgical options are considered; traditional surgeries include trabeculectomy and ab externo aqueous shunts for refractory disease, while minimally invasive glaucoma surgeries (MIGS) such as ab interno microstents may be used in selected patients, including when combined with cataract extraction.
Definitions
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