Canaloplasty
Canaloplasty restores the eye's own drainage system by reopening and stretching Schlemm's canal around its full circumference — lowering pressure without a bleb and, in its ab-interno form, without leaving any implant behind.
What Is Canaloplasty?
Canaloplasty is a minimally invasive glaucoma surgery (MIGS) that works by restoring the eye's own natural drainage rather than bypassing or removing tissue. It reopens and stretches Schlemm's canal — the circular drainage channel that rings the eye — around its entire circumference. Today it is most often performed from inside the eye (ab-interno) using the iTrack microcatheter or the OMNI Surgical System, without an external incision or a bleb.
What Happens Anatomically During the Surgery
Aqueous fluid drains through the trabecular meshwork into Schlemm's canal, and from there into a series of collector channels. Over time in open-angle glaucoma, the canal and its collectors can become narrowed or collapsed, adding resistance beyond the meshwork itself.
Under direct gonioscopic view, the surgeon threads a flexible microcatheter into Schlemm's canal through a tiny opening in the trabecular meshwork and passes it all the way around the 360-degree circumference of the canal. As the catheter is withdrawn, a controlled amount of viscoelastic gel is injected, gently dilating the canal and pushing open the downstream collector channels along the way.
The OMNI system can perform this canal viscodilation and, through the same handpiece, also perform a trabeculotomy (see our Goniotomy page) — addressing both the trabecular meshwork and the canal in a single procedure. The end result is a wider, more open natural drainage pathway and lower eye pressure, using the eye's own outflow system.
Which Types of Glaucoma It Helps
Canaloplasty is well suited to mild-to-moderate open-angle glaucoma, including pseudoexfoliation and pigment dispersion glaucoma, and can be performed as a standalone procedure or combined with cataract surgery. Like other angle- and canal-based MIGS, it relies on a reasonably healthy downstream collector system, so it is not intended for a physically closed angle or for advanced glaucoma requiring a very low target pressure.
Benefits
Canaloplasty offers a distinctive set of advantages among MIGS procedures:
- ✓Restores the eye's natural, full-circumference drainage rather than relying on a single bypass point
- ✓In its ab-interno form, leaves no implant behind and creates no bleb
- ✓Conjunctiva-sparing, preserving trabeculectomy and tube shunt surgery as future options
- ✓Can be combined with a trabeculotomy (OMNI) to treat two points of resistance at once
- ✓Standalone or combined with cataract surgery, with a strong safety profile and quick recovery
Risks & Considerations
Canaloplasty is generally very well tolerated. The most common issue is a small amount of bleeding inside the eye (hyphema) from blood refluxing through the opened canal, which typically clears on its own. Less commonly, eye pressure can rise temporarily in the early postoperative period, the microcatheter may not pass completely around a scarred canal (an incomplete canaloplasty), or a small tear in the inner corneal layer (Descemet membrane detachment) can occur, which is rare. As with all angle- and canal-based procedures, the pressure reduction is moderate, so some patients still need drops or a further procedure.
A related device, the Hydrus Microstent, can be thought of as a scaffold that holds a portion of Schlemm's canal open permanently — a middle ground between canaloplasty and the iStent. The best choice among these depends on each eye's anatomy and your specialist's judgment.
Canaloplasty is one of several MIGS options. For how it compares with the iStent, goniotomy, and the XEN gel stent, see our MIGS Surgery page. For more advanced glaucoma, see our Trabeculectomy and Tube Shunt Surgery pages.
Frequently Asked Questions
What is canaloplasty?
Canaloplasty is a glaucoma procedure that reopens the eye's natural drainage canal (Schlemm's canal). A microcatheter is passed around the full 360 degrees of the canal and viscoelastic gel is injected to dilate it, along with the collector channels, restoring more natural outflow and lowering eye pressure.
What are the OMNI and iTrack systems?
Both are tools used to perform canaloplasty from inside the eye (ab-interno). The iTrack microcatheter is threaded around Schlemm's canal to viscodilate it, and the OMNI Surgical System can both viscodilate the canal and perform a trabeculotomy through the same tiny incision, addressing two points of drainage resistance in one procedure.
Does canaloplasty leave an implant in my eye?
The modern ab-interno canaloplasty performed with OMNI or iTrack leaves no implant behind — it simply reopens your own drainage canal. This keeps the conjunctiva untouched and preserves future surgical options.
Is canaloplasty done with cataract surgery?
It can be performed on its own or combined with cataract surgery through the same incision. Combining the two is common and adds little time or risk to the cataract procedure.
See a glaucoma specialist. Dr. Robert Gunzenhauser is Harvard-educated and UCLA fellowship-trained in glaucoma, providing expert diagnosis and treatment for Canaloplasty (OMNI, iTrack) at Inland Glaucoma Center in Upland, CA.