The goal of glaucoma therapy is to halt disease progression by achieving a significant and sustained reduction in IOP in a manner that has a favorable risk profile. Optimal therapy will differ from patient to patient depending on various factors, including his or her overall health, imminent risk of functional impairment, and concomitant pathologies. Offering patients the best surgical options for the treatment of glaucoma demands that ophthalmologists be trained to perform multiple procedures. I believe that includes canaloplasty, which has been shown to safely and effectively lower IOP in patients with open-angle glaucoma.1 For that reason, I train my fellows and residents how to execute the technique.

EFFICACY

Canaloplasty dilates Schlemm canal and then holds it open permanently with a stent. The goal is to enhance the outflow of aqueous without the creation of a bleb. Threeyear results comparing canaloplasty alone to canaloplasty combined with phacoemulsification demonstrated an important and sustained reduction of IOP accompanied by a decrease in medications.2 In the canaloplasty-alone group (n = 103), a mean baseline IOP of 23.5 ±4.5 mm Hg had dropped to 15.5 ±3.5 mm Hg at 36 months, and the mean number of medications decreased from 1.9 ±0.8 at baseline to 0.9 ±0.9 at 36 months. In the cohort that underwent “phacocanaloplasty” (n = 30), the mean IOP decreased from 23.5 ±5.2 mm Hg at baseline to 13.6 ±3.6 mm Hg at 36 months, and the number of medications dropped from 1.5 ±1.0 to 0.3 ±0.5 over the same time period. This translates to a 34% reduction in IOP and a 53% reduction in medication in canaloplasty-alone patients and a 42% reduction in IOP and an 80% reduction in glaucoma medications in the phacocanaloplasty group. Three years after surgery, 78% of patients in the phacocanaloplasty group were free of medication.

Canaloplasty is less invasive and has fewer complications than filtering procedures.2,3 In the aforementioned study, the incidence of surgical and postsurgical complications was minimal, and hypotony and endophthalmitis did not occur. The investigators concluded that canaloplasty led to a significant and sustained IOP reduction and had an excellent short- and long-term postoperative safety profile. Moreover, postoperative management is more like that for cataract surgery than trabeculectomy.

EFFICIENCY

A popular misconception is that canaloplasty is an extremely difficult procedure to learn as well as a timeconsuming treatment to perform. In my experience, the procedure is efficient in the OR.

For the past 5 years, I have been exposing all of the ophthalmology residents and fellows I oversee to canal-based procedures and training those who are interested to perform canaloplasty. I find that fellows and residents are not apprehensive about trying something new and are not set in their techniques and skill sets. Moreover, I think that fellowship programs that teach several kinds of procedures are, quite simply, more attractive to prospective fellows. Programs may lose top candidates if they do not ensure that these individuals will finish training with the ability to offer patients a wide spectrum of procedural options.

At Dean McGee Eye Institute, we have just begun a study to evaluate residents' and fellows' surgical learning curves and efficacy at performing canaloplasty. I have observed that residents and fellows are able to perform the procedure efficiently and achieve successful outcomes. The initial feedback I have received from residents and fellows indicates that they do not find performing canaloplasty to be particularly difficult; in fact, third-year residents and fellows routinely complete the procedure in 25 minutes. I have found that glaucoma specialists who routinely perform canaloplasty report an average surgical time of less than 15 minutes.

I suspect that the reason for the misconceptions about canaloplasty is ophthalmologists' general lack of experience at dissecting down to the Schlemm canal. As surgeons strive to move away from bleb-based procedures, it is imperative that they train residents and fellows to perform, or at least expose them to, canal-based surgeries. Students have the option of referring patients to the attending physician if needed, which helps eliminate any hesitation they may have.

CONCLUSION

A number of patients do not adhere to or are intolerant of prescribed topical therapy.4-6 Until recently, the glaucoma community has lacked an effective and efficient surgical option by which to reduce or eliminate patients' need for medication without subjecting them to traditional blebbased surgery. Canaloplasty allows surgeons to treat glaucoma sooner in the disease course while minimizing possible complications and preserving future surgical options. Canaloplasty is not a panacea. When I was a resident searching for a glaucoma fellowship program, however, I strongly believed that the best programs offer a full spectrum of procedural options, because surgeons want to leave training armed with all of the tools required to better treat patients. For this reason, I strive to educate my residents and fellows on a range of procedures, and I encourage other surgeons to do so as well.

Mahmoud A. Khaimi, MD, is a clinical associate professor of ophthalmology at the Dean McGee Eye Institute, University of Oklahoma College of Medicine, Oklahoma City. He is a consultant to and a speaker for iScience Interventional. Dr. Khaimi may be reached at (405) 271-1093; mahmoud-khaimi@dmei.org.

  1. Harvey BJ, Khaimi MA. A review of canaloplasty. Saudi Journal of Ophthalmology. 2011;25:329-336.
  2. 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.
  3. Gedde SJ, Schiffman JC, Feuer WJ, et al. Three-year follow-up of the Tube Versus Trabeculectomy Study. Am J Ophthalmol. 2009;148:670-684.
  4. Friedman DS, Quigley HA, Gelb L, et al. Using pharmacy claims data to study adherence to glaucoma medications: methodology and findings of the Glaucoma Adherence and Persistency Study (GAPS). Invest Ophthalmol Vis Sci. 2007;48(11):5052-5057.
  5. Nordstrom BL, Friedman DS, Mozaffari E, et al. Persistence and adherence with topical glaucoma therapy. Am J Ophthalmol. 2005;140(4):598.e1-11.
  6. Winfield AJ, Jessiman D, Williams A, Esakowitz L. A study of the causes of noncompliance by patients prescribed eyedrops. Br J Ophthalmol. 1990;74:477-480.