Blue Cross Blue Shield of Minnesota Medical Policy


Medical Policy:
Viscocanalostomy and Canaloplasty for the Treatment of Glaucoma
Effective Date:
June 1, 2020
Issued Date:
May 31, 2021
Last Revision Date:
May 2020
Annual Review:
May 2021

This policy version was replaced May 30, 2022. To find the newest version, go to, read and accept the Blue Cross Medical Policy Statement, then select “Blue Cross and Blue Shield of Minnesota Medical Policies.” This will bring up the Medical Policy search screen. Enter the policy number without the version number (last 3 digits).

Glaucoma surgery is intended to reduce intraocular pressure (IOP) when the target IOP cannot be reached with medications. Due to complications with established surgical approaches (e.g., trabeculectomy), alternative surgical treatments, including transluminal dilation by viscocanalostomy or canaloplasty, are being evaluated for patients with glaucoma.

Trabeculectomy is the most established surgical procedure for glaucoma, allowing aqueous humor to directly enter the subconjunctival space. This procedure creates a subconjunctival reservoir with a filtering “bleb” on the eye, which can effectively reduce IOP, but is associated with numerous and sometimes sight-threatening complications (e.g., leaks, hypotony, choroidal effusions and hemorrhages, hyphemas or bleb-related endophthalmitis) and long-term failure.

Alternative nonpenetrating methods are being evaluated to treat glaucoma are viscocanalostomy and canaloplasty. Viscocanalostomy is a variant of deep sclerectomy and unroofs and dilates the Schlemm canal without penetrating the trabecular meshwork or anterior chamber. A high-viscosity viscoelastic solution (e.g., sodium hyaluronate) is used to open the canal and create a passage from the canal to a scleral reservoir. It has been proposed that viscocanalostomy may lower IOP while avoiding bleb-related complications.

Canaloplasty, which evolved from viscocanalostomy, involves dilation and tension of the Schlemm canal with a suture loop between the inner wall of the canal and the trabecular meshwork. This ab externo procedure uses the iTrack illuminated microcatheter to access and dilate the length of the Schlemm canal and to pass the suture loop through the canal. An important difference between viscocanalostomy and canaloplasty is that canaloplasty attempts to open the entire length of the Schlemm canal, rather than one section of it.

In 2004, iTrack™ was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process as a surgical ophthalmic microcannula that is indicated for the general purpose of “fluid infusion and aspiration, as well as illumination, during surgery.” In 2008, iTrack™ was cleared by FDA for “catheterization and viscodilation of [the] Schlemm canal to reduce intraocular pressure in adult patients with open angle glaucoma.”

This policy is designed to address medical guidelines that are appropriate for the majority of individuals with a particular disease, illness, or condition. Each person's unique clinical circumstances may warrant individual consideration, based on review of applicable medical records.

Policy Position Coverage is subject to the specific terms of the member's benefit plan.

I.   Canaloplasty may be considered MEDICALLY NECESSARY AND APPROPRIATE as a method to reduce intraocular pressure (IOP) in patients with chronic primary open-angle glaucoma under the following conditions:

  • The patient has tried and failed 2 medical therapy options (e.g. prostaglandin analog:  latanoprost, beta-blocker:  timolol, alpha-adrenergic agonist:  brimonidine, topical carbonic anhydrase inhibitor: dorzolamide); AND
  • The patient is not a candidate for any other IOP-lowering procedure (e.g. trabeculectomy or glaucoma drainage implant) due to a high risk for complications due to ocular surface diseases (e.g. severe dry eye, ocular pemphigoid).

II.  Canaloplasty is considered EXPERIMENTAL/INVESTIGATIVE for all other indications, including angle-closure glaucoma, due to lack of clinical evidence demonstrating an impact on improved health outcomes.

III. Viscocanalostomy is considered EXPERIMENTAL/INVESTIGATIVE under all indications, including angle-closure glaucoma, due to lack of clinical evidence demonstrating an impact on improved health outcomes.

66174 66175

Denial Statements

No additional statements.


Blue Cross and Blue Shield of Minnesota medical policies apply generally to all Blue Cross and Blue Plus plans and products. Benefit plans vary in coverage and some plans may not provide coverage for certain services addressed in the medical policies. When determining coverage, reference the member’s specific benefit plan, including exclusions and limitations.

Medicaid products may provide different coverage for certain services, which may be addressed in different policies. For Minnesota Health Care Program (MHCP) policies, please consult the MHCP Provider Manual website.

Medicare products may provide different coverage for certain services, which may be addressed in different policies. For Medicare National Coverage Determinations (NCD), Local Coverage Determinations (LCD), and/or Local Coverage Articles, please consult CMS, National Government Services, or CGS websites. 

Note that services with specific coverage criteria may be reviewed retrospectively to determine if criteria are being met. Retrospective denial of claims may result if criteria are not met.

Blue Cross and Blue Shield of Minnesota reserves the right to revise, update and/or add to its medical policies at any time without notice. Codes listed on this policy are included for informational purposes only and are subject to change without notice. Inclusion or exclusion of a code does not constitute or imply member coverage or provider reimbursement. 

These guidelines are the proprietary information of Blue Cross and Blue Shield of Minnesota. Any sale, copying or dissemination of the medical policies is prohibited; however, limited copying of medical policies is permitted for individual use.


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