Clinical UM Guideline

This document addresses canaloplasty, which is a form of non-penetrating glaucoma surgery.

Canaloplasty is proposed as an alternative to trabeculectomy, the traditional surgical treatment of primary open-angle glaucoma (POAG).

Note: Please see the following related document for additional information:

• CG-SURG-124 Viscocanalostomy

Medically Necessary:

Canaloplasty is considered medically necessary for the treatment of primary open-angle glaucoma (POAG).

Not Medically Necessary:

Canaloplasty is considered not medically necessary for all other indications.

The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Medically Necessary:

When services are Not Medically Necessary:
For the procedure codes listed above for all other diagnoses not listed.

Surgical intervention becomes necessary in managing glaucoma if medication fails to sufficiently lower intraocular pressure (IOP). The standard surgical procedure used as a benchmark for comparison is trabeculectomy. This operation creates a conjunctival reservoir, known as a "filtering bleb," to decrease IOP by facilitating the flow of aqueous humor into the subconjunctival space. One alternative surgical technique is canaloplasty, which involves dilating the entire Schlemm's canal using a suture loop between the canal and the trabecular meshwork with a specialized microcatheter device (iTrack™).

Lewis and colleagues (2007) performed a nonrandomized, uncontrolled study of 94 individuals who underwent a canaloplasty for POAG with an IOP of at least 16 mm Hg or higher. A total of 74 individuals had successful tension suture placement with a resulting mean IOP of 15.3 ± 3.8 mm Hg at 1 year postop compared to a mean IOP of 24.7 ± 4.8 mm Hg at baseline. However, at 1 year, only 48 of the 74 individuals had follow-up. Many uncontrolled variables were noted such as suture placement versus no suture placement, and cataract surgery with canaloplasty versus canaloplasty alone, which could influence the results. It is unclear how the uncontrolled variables and those lost to follow-up affected study results. In addition to the uncontrolled variables, this study was limited by lack of randomization.

In an international, multicenter, prospective study, Shingleton and colleagues (2008) evaluated the safety and efficacy of canaloplasty to treat open-angle glaucoma combined with clear corneal phacoemulsification and posterior chamber intraocular lens implantation. Data from 54 eyes that had combined glaucoma and cataract surgery performed by 11 surgeons at nine study sites were examined. The Schlemm canal and anterior segment angle morphology were assessed by intraoperative and postoperative high-resolution ultrasound imaging. Upon comparison of baseline with postoperative data, it was found that postoperatively the mean baseline IOP had decreased at 1 month, 3 months, 6 months, and 12 months. Medication usage had also decreased at 12 months postoperatively. Surgical complications occurred in 5 eyes and included hyphema, Descemet tear, and iris prolapse. Limitations of this study include lack of randomization and lack of a control group. The authors noted that “additional studies to evaluate this new technique in relation to existing treatments as well as other types of glaucoma are recommended.”

In an ongoing international, multi-center, prospective, open-label study, Lewis and colleagues (2009) evaluated the 2-year post-surgical safety and efficacy of canaloplasty performed for the treatment of OAG. The study group consisted of 127 individuals (127 eyes) of which 97 eyes (76%) had canaloplasty alone and 30 eyes (24%) with significant cataracts had a combined glaucoma-cataract surgery (phacocanaloplasty). Primary outcome measures included IOP and glaucoma medication use. The authors reported that at 24 months, all 127 eyes had a mean IOP of 16.0 mm Hg ± 4.2 standard deviation (SD) and mean glaucoma medication use of 0.5 ± 0.8 (baseline values 23.6 ± 4.8 mm Hg and 1.9 ± 0.8 medications). Eyes with canaloplasty alone had a mean IOP of 16.3 ± 3.7 mm Hg and 0.6 ± 0.8 medications (baseline values 23.2 ± 4.0 mm Hg and 2.0 ± 0.8 medications). Eyes with a combined glaucoma-cataract surgery had a mean IOP of 13.4 ± 4.0 mm Hg and 0.2 ± 0.4 medications (baseline values 23.1 ± 5.5 mm Hg and 1.7 ± 1.0 medication). Also at 24 months, 3 eyes (3%) had lost visual acuity. Of these eyes, 1 had posterior capsule opacification, 1 had a dense cataract, and 1 had an unspecified reason for the visual acuity decrease. A total of 20 (15.7%) of 127 individuals did not meet study analysis criteria due to missed visits. There were 13 post-surgical complications reported in 10 eyes and also 3 complications noted during surgery. Complications reported included suture extrusion, hyphema, and IOP elevation. Limitations of this study included lack of randomization. There was flexibility in individual selection and treatment according to each investigator’s current practice. The authors noted “the study design includes additional follow-up and reporting with more extensive subgroup analysis anticipated during the continuing study.”

Mosaed and colleagues (2009) performed a literature review comparing traditional (trabeculectomy) and novel glaucoma surgical techniques which included canaloplasty. The authors concluded that trabeculectomy remains the most effective IOP lowering procedure to date; however, it has the highest risk of severe complications. In addition, the authors indicated that canaloplasty may not be able to regularly achieve the lower IOP required in advanced glaucoma.

Grieshaber and colleagues (2010) reported on a prospective, single-center study evaluating canaloplasty in 60 randomly selected eyes of 60 consecutive African individuals with POAG. The mean preoperative IOP was 45.0 ± 12.1 mm Hg. The mean follow-up time was 30.6 ± 8.4 months. The mean IOP at 12 months was 15.4 ± 5.2 mm Hg (n=54), at 24 months 16.3 ± 4.2 mm Hg (n=51) and at 36 months 13.3 ± 1.7 mm Hg (n=49). For IOP ≤ 21 mm Hg, the complete success rate (without medications) was 77.5% and qualified success rate (with or without medications) was 81.6% at 36 months.

Grieshaber and colleagues (2011) reported on an additional prospective, single-center study which aimed to assess the safety and efficacy of canaloplasty. This procedure was performed in 32 eyes of 32 consecutive individuals with medically uncontrolled OAG and a follow-up time of over 1 year. The mean preoperative IOP dropped from 27.3 ± 5.6 mm Hg to 12.8 ± 1.5 mm Hg at 12 months and was 13.1 ± 1.2 mm Hg at 18 months (p<0.001). The complete success rate of an IOP ≤ 21, 18, and 16 mm Hg was 93.8% (95% confidence interval [CI], 0.86-1.0), 84.4% (95% CI, 0.73-0.98), and 74.9% (95% CI, 0.61-0.92), respectively, at 12 months. The authors concluded that canaloplasty was an efficient method in lowering IOP in OAG in this series, but the procedure had its own distinct risk profile, and comparative, randomized, long-term studies are needed to draw final conclusions.

Lewis and colleagues (2011) followed up on their 2007 and 2009 nonrandomized, multicenter studies and reported 3-year results addressing the safety and efficacy of canaloplasty. The study cohort consisted of adults with OAG having had canaloplasty or combined cataract-canaloplasty surgery. At 3 years after surgery, all eyes studied (n=157) had a mean IOP of 15.2 mm Hg ± 3.5 (SD) and mean glaucoma medication use of 0.8 ± 0.9 compared with a baseline IOP of 23.8 ± 5.0 mm Hg on 1.8 ± 0.9 medications. Eyes having undergone combined cataract-canaloplasty surgery had a mean IOP of 13.6 ± 3.6 mm Hg while on 0.3 ± 0.5 medications compared with a baseline IOP of 23.5 ± 5.2 mm Hg on 1.5 ± 1.0 medications. IOP and medication use results in all eyes were decreased from baseline at every time point (p<0.001). Late postoperative complications included cataracts (12.7%), transient IOP elevation (6.4%), and partial suture extrusion through the trabecular meshwork (0.6%).

Bull and colleagues (2011) reported 3-year results of a European, prospective, multi-center, interventional study consisting of 109 eyes of 109 adults with open-angle glaucoma undergoing canaloplasty or combined cataract-canaloplasty surgery. Primary outcome measures included IOP, glaucoma medication usage, and adverse events. Eyes with canaloplasty showed a mean baseline IOP of 23.0 ± 4.3 mm Hg and mean glaucoma medication usage of 1.9 ± 0.7 medications, which decreased to a mean IOP of 15.1 ± 3.1 mm Hg on 0.9 ± 0.9 medications at 3 years postoperatively. Eyes with combined cataract-canaloplasty surgery showed a mean baseline IOP of 24.3 ± 6.0 mm Hg on 1.5 ± 1.2 medications, which decreased to a mean IOP of 13.8 ± 3.2 mm Hg on 0.5 ± 0.7 medications at 3 years. Intraocular pressure and medication use results for all study eyes were significantly decreased from baseline at all intervals (p<0.00001). Late postoperative complications included transient IOP elevation (1.8%) and cataracts (19.1%). The authors concluded that predictive factors for successful canaloplasty outcomes and reasons for later failure remain unclear and should be explored in future studies.

In a retrospective case series, Ayyala and colleagues (2011) compared individual outcomes through 12 months of follow-up post canaloplasty and trabeculectomy procedures. Individuals with open-angle glaucoma who underwent either canaloplasty (33 eyes of 33 subjects) or trabeculectomy with mitomycin C (46 eyes of 46 subjects) to control IOP between January 2007 and December 2008 were included. A single surgeon performed all surgeries. Primary outcome measures were: change in IOP, visual acuity, postoperative medications, failure based on IOP (> 18 or < 4 mm Hg at 1 year) or second operative procedure (any eye requiring reoperation) and complication rates at 12 months. There were no differences in demographics, previous surgery, or preoperative and postoperative visual acuity between the groups. The mean percentage of reduction in IOP from preoperative values at 12 months after surgery was 32% (± 22%) for the canaloplasty group compared with 43% (± 28%) for the trabeculectomy group. The median reduction in the number of medications at 12 months follow-up was 2 in the canaloplasty group and 3 in the trabeculectomy group. A higher percentage of those treated with canaloplasty than trabeculectomy (36% vs. 20%) required postoperative medications. Failure based on IOP (IOP > 18 or < 4 mm Hg at 12 months) was 12.1% (4/33 subjects) for the canaloplasty group and 4.3% (2/46 subjects) for the trabeculectomy group. Surgical failure rates for the canaloplasty group (n=5, 15%) and trabeculectomy group (n=5, 11%) were comparable. The authors concluded that these results need to be confirmed by a prospective, randomized, longitudinal study. Limitations of this study included small size and limited duration of follow-up.

Rulli and colleagues (2013) conducted a systematic review and meta-analysis of comparative studies of two or more surgical techniques (one of which had to be Trabeculectomy [TE]), including individuals with open-angle glaucoma. Comparisons were made between TE and the main types of nonpenetrating surgery (NPS) (deep sclerectomy, viscocanalostomy, and canaloplasty). The primary outcome was the mean between-group difference in the reduction in diurnal IOP from baseline to the 6- or 12-month follow-up evaluation. A total of 18 articles, consisting of 20 comparisons, were analyzed. The 6-month follow-up data demonstrated that the pooled estimate of the mean between-group difference was −2.15 mm Hg (95% CI, −2.85 to −1.44) in favor of TE. There was no difference between the NPS subgroups. The absolute risk of hypotony, choroidal effusion, cataract, and flat or shallow anterior chamber was higher in the TE group than in the NPS group. The authors concluded that trabeculectomy seemed to be the most effective surgical procedure for reducing IOP in individuals with open-angle glaucoma. However, it was associated with a higher incidence of complications when compared with NPS.

Brusini and colleagues (2014) performed a 3-year follow-up from an independent series of 214 individuals treated with canaloplasty in Europe. Mean IOP was reduced from 29.4 mm Hg at baseline to 17.0 mm Hg after excluding 17 subjects (7.9%) who later underwent trabeculectomy. IOP was 21 mm Hg or lower in 86.2% of subjects, 18 mm Hg or lower in 58.6%, and 16 mm Hg or lower in 37.9%. There was a decrease in mean medication use, from 3.3 at baseline to 1.3 at follow-up. Complications, which included hyphema, Descemet membrane detachment, IOP spikes, and hypotony, were fewer than is usually seen with trabeculectomy. Disadvantages of canaloplasty that were reported included the inability to complete the procedure in 16.4% of eyes, a long and rather steep surgical learning curve, the need for specific instruments, and an average postoperative IOP level that tended to not be very low.

A small, prospective clinical trial by Matlach and colleagues (2015) consisted of 62 eyes of 62 Caucasian subjects with uncontrolled, open-angle glaucoma randomized to either a trabeculectomy (n=32) or canaloplasty (n=30). Both surgeries were performed by a single glaucoma surgeon at a single European center, and all subjects were followed for 2 years postoperatively. A significant reduction of intraocular pressure (IOP) occurred in both groups. Mean absolute IOP reduction was 10.8 ± 6.9 mm Hg in the trabeculectomy and 9.3 ± 5.7 mm Hg in the canaloplasty group after 2 years. Mean IOP was 11.5 ± 3.4 mm Hg in the trabeculectomy and 14.4 ± 4.2 mm Hg in the canaloplasty group after 2 years. Complications were more common in the trabeculectomy group and included choroidal detachment (12.5%), hypotony (37.5%), and elevated IOP (25.0%). The authors concluded that trabeculectomy allowed for a stronger decrease of IOP with less need for medication, and canaloplasty had a lower complication rate. Limitations of this study included a small sample size.

Zhang and colleagues (2017) published a systematic review and meta-analysis on the efficacy and safety of canaloplasty compared to trabeculectomy. Using a baseline of 28 studies published before April 1, 2016, the researchers compared 1-year, post-procedure outcomes for 1498 eyes. Trabeculectomy was more efficient in IOP reduction than canaloplasty (MeD 3.61 mm Hg; 95% CI, 1.69 to 5.53). For both procedures, there was a similar reduction in the need for glaucoma medications (MeD –0.37 mm Hg; 95% CI, –0.83 to 0.08). Adverse events included hyphema (≥ 1 mm), which was higher in the canaloplasty group (OR 9.24; 95% CI, 3.09 to 27.60), and hypotony, which was higher in the trabeculectomy group (OR 0.32; 95% CI, 0.13 to 0.80). In addition, trabeculectomy had higher incidences of choroidal effusion or detachment (OR 0.25; 95% CI, 0.06 to 0.97). Some adverse events were specific to the procedure, with incidences of Descemet membrane attachment in the canaloplasty group only (3%), and incidences of suprachoroidal hemorrhage and bleb needling in the trabeculectomy group only (2.3% and 10.9%, respectively). The researchers concluded that trabeculectomy was more effective than canaloplasty in reducing IOP, but trabeculectomy had more complications. The researchers concluded that high-quality, randomized controlled trials are needed to verify the findings.

Liu and colleagues (2017) analyzed the safety and efficacy of canaloplasty versus trabeculectomy for the treatment of glaucoma. The researchers pooled data from 8 included studies published between 2010 and 2015, focusing on complications and intraocular pressure at 6 and 12 months post-procedure. The researchers did not find a difference in intraocular pressure at 6 months; however, at 12 months, the intraocular pressure was higher in the canaloplasty group (weighted mean difference [WMD] 1.90; 95% CI, 0.12 to 3.69; p<0.05). The canaloplasty group was more likely to have hyphema (RR 2.96; 95% CI, 1.51 to 5.83), but less likely to have hypotony (RR 0.30; 95% CI, 0.11 to 0.83) and postoperative choroid abnormalities (RR 0.24; 95% CI, 0.09 to 0.66). The researchers concluded that trabeculectomy “can significantly reduce the intraocular pressure better than canaloplasty method in glaucoma patients after operation,” and “trabeculectomy leads a more marked IOP decrease than canaloplasty at the cost of a higher complication rate.”

Khaimi and colleagues (2017) published 3-year outcomes following canaloplasty for the treatment of open-angle glaucoma. The researchers retrospectively reviewed charts at a single center to gather a cohort of 277 eyes treated by canaloplasty. Primary endpoints were the mean IOP and mean number of glaucoma medications at each follow-up visit and secondary endpoints were surgical and post-surgical complications. The overall baseline IOP of 19.7 mmHg was reduced to 15.2 mmHg at 3 years (p<0.001). Average medication usage was reduced from a baseline of 2.1 to 0.6 at 3 years (p<0.001). Hyphema was present postoperatively in 144 eyes (52.8%) but was resolved in 125 of those eyes in 3 months. Baseline mean visual acuity was 0.31 ± 0.35 with a mean Snellen fraction of 20/41.1. At 3 years (n=65), mean visual acuity was 0.20 ± 0.24 with a Snellen fraction of 20/31.5 (p=0.29). The authors noted that visual acuity “worsens significantly after surgery but may return to preoperative values by around 3-12 months postoperatively.” The researchers concluded “the risk profile of canaloplasty was favorable and consistent with the well-documented, lower risks associated with other nonpenetrating procedures.” The study was limited by a retrospective design and loss to follow-up.

Gabai and colleagues (2019) analyzed the efficacy and safety of trabeculectomy versus nonpenetrating glaucoma surgery, including deep sclerectomy, viscocanalostomy, and canaloplasty. The researchers searched for published peer-reviewed data until January 10, 2018. A total of 21 studies were included in the analysis. Combined weighted mean difference (WMD) between initial and final IOP, favored trabeculectomy compared with nonpenetrating glaucoma surgery at 6 months (WMD=2.12 mm HG; 95% CI, 1.62 to 2.63; I²=0%; P=0.510), at 12 months (WMD=2.53 mm Hg; 95% CI, 1.72 to 3.34; I²=58.5%; P=0), and 24 months (WMD=2.13 mm Hg; 95% CI, 0.89 to 3.36; I²=5.72%; P=0.01). The researchers noted the results might indicate trabeculectomy as the best choice for individuals where lower postsurgical IOP is desirable and who have a higher risk for glaucoma progression requiring a more IOP reduction. In regard to safety, more complications were observed with trabeculectomy than nonpenetrating glaucoma surgery. The researchers concluded that further studies with larger samples and longer follow-up are needed to evaluate long-term efficacy and safety of trabeculectomy and nonpenetrating glaucoma surgery.

Vastardis and colleagues (2021) conducted a 12-month follow-up, retrospective, single-surgeon, single-center study to compare the efficacy of trabeculectomy with mitomycin and ab externo canaloplasty. The study excluded individuals with previous glaucoma surgery, intraoperative conversion of surgery or failure to complete, glaucoma surgery with phacoemulsification, cataracts, age-related macular degeneration, retinal pathology, prior pars plana vitrectomy surgery, and corneal pathologies. This yielded 104 eyes that underwent ab externo canaloplasty (group A) and 136 eyes that underwent trabeculectomy with mitomycin (group B). The IOP was reduced from 20.45 ± 7.76 to 13.87 ± 3.34 mm HG (32.17% IOP reduction) in group A and from 23.44 ± 7.56 to 10.54 ± 3.98 mm Hg (55.04% IOP reduction) in group B. Hyphema (30.76%) was the most common complication in group A. Choroidal detachment due to hypotony was the most common post-operative complication (12.5%). The authors concluded both surgeries provided good results in reducing IOP.

The American Academy of Ophthalmology (AAO) Preferred Practice Pattern for POAG (2020) states:

The goals of managing patients with POAG are as follows:

• Control of IOP in the target range
• Stable optic nerve/RNFL status
• Stable visual fields

The effects of treatment, as well as, the patient’s quality of life, comorbidities, and life expectancy are to be considered in the decision-making process about therapy.

The rationale for nonpenetrating glaucoma surgery is that by avoiding a continuous passageway from the anterior chamber to the subconjunctival space, the incidence of complications such as bleb-related problems and hypotony can be reduced. The nonpenetrating procedures have a higher degree of surgical difficulty compared with trabeculectomy and they require special instrumentation.

Viscocanalostomy: Viscocanalostomy includes deep sclerectomy along with expansion of Schlemm’s canal using an ophthalmic viscoelastic device. The procedure is intended to allow passage of aqueous humor through the trabeculodescemetic membrane window and into the physiologic outflow pathway through Schlemm’s canal. Randomized clinical trials comparing viscocanalostomy with trabeculectomy suggest greater IOP reduction with trabeculectomy but fewer complications with viscocanalostomy. A 2014 Cochrane Systematic Review found some limited evidence that control of IOP was better with trabeculectomy than with viscocanaloplasty, but conclusions could not be drawn for deep sclerectomy, and quality of life outcomes may be needed to differentiate among procedures. Thus, the selection of viscocanalostomy and deep sclerectomy over trabeculectomy should be left to the discretion of the treating ophthalmologist, in consultation with the individual patient. (I-, Insufficient Quality, Strong Recommendation)

Canaloplasty: In canaloplasty, circumferential viscodilation of Schlemm’s canal using a flexible microcatheter is performed in combination with deep sclerectomy. Dilating the entire canal aims to give aqueous humor access to a greater number of collector channels. A 10-0 polypropylene (Prolene) suture is placed with appropriate tension within Schlemm’s canal when possible to apply inward directed tension on the trabecular meshwork. The safety and efficacy of canaloplasty alone and combined with phacoemulsification was described in a nonrandomized, multicenter clinical trial through 3 years of follow-up. A retrospective case series found lower postoperative IOP with trabeculectomy compared with canaloplasty. In a randomized clinical trial comparing trabeculectomy and canaloplasty, patients in the trabeculectomy group achieved higher success rates and required fewer medications than those in the canaloplasty group, but they also experienced a higher rate of late hypotony.

The severity of glaucoma damage can be estimated according to the following categories:

• Mild: Definite optic disc, RNFL, or macular imaging abnormalities consistent with glaucoma as detailed above and a normal visual field as tested with standard automated perimetry (SAP)
• Moderate: Definite optic disc, RNFL, or macular imaging abnormalities consistent with glaucoma as detailed above, and visual field abnormalities in one hemifield that are not within 5 degrees of fixation
• Severe: Definite optic disc, RNFL, or macular imaging abnormalities consistent with glaucoma as detailed above, and visual field abnormalities in both hemifields and/or loss within 5 degrees of fixation in at least one hemifield as tested with SAP
• Indeterminate: Definite optic disc, RNFL, or macular imaging abnormalities consistent with glaucoma as detailed above, inability of patient to perform visual field testing, unreliable/uninterpretable visual field test results, or visual fields not yet performed

Yadgarov and colleagues (2023) conducted a study to evaluate the long-term safety and efficacy of sequential canaloplasty and trabeculotomy combined with cataract surgery in patients with varying stages of open-angle glaucoma. It analyzed case records of 171 consecutive patients who underwent these procedures, focusing on changes in intraocular pressure (IOP) and medication use over 12 and 24 months postoperatively. The results showed a significant reduction in IOP from a baseline of 17.2 mmHg on 1.3 medications to 14.3 mmHg on 0.8 medications at 12 months and 14.0 mmHg on 0.9 medications at 24 months (p<0.001). Specifically, patients with advanced glaucoma also demonstrated significant IOP reduction. Kaplan-Meier survival analysis indicated a 93% probability of avoiding secondary surgical interventions at 2 years post-surgery. The study concluded that the combined procedures effectively reduced IOP across all glaucoma stages, maintaining a high rate of secondary surgical interventions avoidance.

Hyphema: Bleeding in the eye.

Schlemm’s canal: A circular canal in the eye that drains aqueous humor from the anterior chamber of the eye into the anterior ciliary veins.

Trabecular tissue: A mesh-like structure inside the eye at the iris-scleral junction of the anterior chamber angle; filters aqueous fluid and controls its flow into the canal of Schlemm, prior to its leaving the anterior chamber.

Peer Reviewed Publications:

1. Ayyala RS, Chaudhry AL, Okogbaa CB, Zurakowski D. Comparison of surgical outcomes between canaloplasty and trabeculectomy at 12 months' follow-up. Ophthalmology. 2011; 118(12):2427-2433.
2. Brusini P. Canaloplasty in open-angle glaucoma surgery: a four-year follow-up. ScientificWorldJournal. 2014; 2014:469609.
3. Bull H, von Wolff K, Körber N, Tetz M. Three-year canaloplasty outcomes for the treatment of open-angle glaucoma: European study results. Graefes Arch Clin Exp Ophthalmol. 2011; 249(10):1537-1545.
4. Gabai A, Cimarosti R, Battistella C, et al. Efficacy and safety of trabeculectomy versus nonpenetrating surgeries in open-angle glaucoma: a meta-analysis. J Glaucoma. 2019 Sep; 28(9):823-833.
5. Godfrey DG, Fellman RL, Neelakantan A. Canal surgery in adult glaucomas. Curr Opin Ophthalmol. 2009; 20(2):116-121.
6. Grieshaber MC, Fraenkl S, Schoetzau A, et al. Circumferential viscocanalostomy and suture canal distension (canaloplasty) for whites with open-angle glaucoma. J Glaucoma. 2011; 20(5):298-302.
7. Grieshaber MC, Peckar C, Pienaar A, et al. Long-term results of up to 12 years of over 700 cases of viscocanalostomy for open-angle glaucoma. Acta Ophthalmol. 2015; 93(4):362-367.
8. Grieshaber MC, Pienaar A, Olivier J, Stegmann R. Canaloplasty for primary open-angle glaucoma: long-term outcome. Br J Ophthalmol. 2010; 94(11):1478-1482.
9. Khaimi MA, Dvorak JD, Ding K. An analysis of 3-year outcomes following canaloplasty for the treatment of open-angle glaucoma. J Ophthalmol. 2017; 2017:2904272.
10. Lewis RA, von Wolff K, Tetz M, et al. Canaloplasty: circumferential viscodilation and tensioning of Schlemm's canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: interim clinical study analysis. J Cataract Refract Surg. 2007; 33(7):1217-1226.
11. Lewis RA, von Wolff K, Tetz M, et al. Canaloplasty: circumferential viscodilation and tensioning of Schlemm canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: two-year interim clinical study results. J Cataract Refract Surg. 2009; 35(5):814-824.
12. Lewis RA, von Wolff K, Tetz M, et al. Canaloplasty: three-year results of circumferential viscodilation and tensioning of Schlemm canal using a microcatheter to treat open-angle glaucoma. J Cataract Refract Surg. 2011; 37(4):682-690.
13. Liu H, Zhang H, Li Y, Yu H. Safety and efficacy of canaloplasty versus trabeculectomy in treatment of glaucoma. Oncotarget. 2017; 8(27):44811-44818.
14. Matlach J, Dhillon C, Hain J, et al. Trabeculectomy versus canaloplasty (TVC study) in the treatment of patients with open-angle glaucoma: a prospective randomized clinical trial. Acta Ophthalmol. 2015; 93(8):753-761.
15. Mosaed S, Dustin L, Minckler DS. Comparative outcomes between newer and older surgeries for glaucoma. Trans Am Ophthalmol Soc. 2009; 107:127-133.
16. Rulli E, Biagioli E, Riva I, et al. Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis. JAMA Ophthalmol. 2013; 131(12):1573-1582.
17. Shingleton B, Tetz M, Korber N. Circumferential viscodilation and tensioning of Schlemm canal (canaloplasty) with temporal clear corneal phacoemulsification cataract surgery for open-angle glaucoma and visually significant cataract: one-year results. J Cataract Refract Surg. 2008; 34(3):433-440.
18. Vastardis I, Fili S, Perdikakis G, et al. Estimation of risk-benefit ratio and comparison of post-operative efficacy results between trabeculectomy and canaloplasty. Eur J Ophthalmol. 2021 May; 31(3):1405-1412.
19. Wagdy FM. Canaloplasty versus viscocanalostomy in primary open angle glaucoma. Electron Physician. 2017 Jan 25; 9(1):3665-3671.
20. Yadgarov A, Dentice K, Aljabi Q. Real-World Outcomes of Canaloplasty and Trabeculotomy Combined with Cataract Surgery in Eyes with All Stages of Open-Angle Glaucoma. Clin Ophthalmol. 2023 Sep 1;17:2609-2617.
21. Zhang B, Kang J, Chen X. A system review and meta-analysis of canaloplasty outcomes in glaucoma treatment in comparison with trabeculectomy. J Ophthalmol. 2017; (5):1-9.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American Academy of Ophthalmology (AAO). Primary Open angle glaucoma. Preferred Practice Pattern. Revised September 12, 2020. For additional information visit the AAO website: http://one.aao.org. Accessed on October 18, 2024.
2. Eldaly MA, Bunce C, Elsheikha OZ, Wormald R. Non-penetrating filtration surgery versus trabeculectomy for open-angle glaucoma. Cochrane Database Syst Rev. 2014;(2):CD007059.
3. Francis BA, Singh K, Lin SC, et al. Novel glaucoma procedures: a report by the American Academy of Ophthalmology. Ophthalmology. 2011; 118(7):1466-1480.
4. U.S. Food and Drug Administration 510(k) Premarket Notification Database. Summary of Safety and Effectiveness. iScience Interventional Ophthalmic Microcatheter. No. K080067. Rockville, MD: FDA. July 18, 2008. Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf8/K080067.pdf. Accessed on October 18, 2024.
5. U.S. Food and Drug Administration 510(k) Premarket Notification Database. Summary of Safety and Effectiveness. OMNI Surgical System. No. K232214. Rockville, MD: FDA. August 25, 2023. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K232214. Accessed on October 18, 2024.

1. National Institutes of Health, the National Eye Institute. Facts about Glaucoma. Available at: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma. Accessed on October 18, 2024.

Canaloplasty
iTrack^™ Microcatheter

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.