Nova Eye Medical Limited has reported the recent publication of three investigator-led, retrospective case series which evaluated the long-term effectiveness of canaloplasty in patients with open-angle glaucoma (OAG) over 36- and 48-month periods, and in post-keratoplasty patients.
Performed by MIGS surgeon Mark J. Gallardo, MD, El Paso Eye Surgeons, Texas, USA and published in the March 2022 issue of Ophthalmology Glaucoma, a journal collaboration between the American Academy of Ophthalmology and the American Glaucoma Society, the 36-month case series demonstrated a significant reduction in mean intraocular pressure (IOP) as compared to baseline, along with a significant decrease in the mean number of glaucoma medications, following canaloplasty performed with the company’s proprietary iTrack device.
Performed by Prof Norbert Koerber and Dr Simon Ondrejka, glaucoma surgeons at the Augencentrum Köln-Porz, Germany and published in the April 2022 issue of Klinische Monatsblätter für Augenheilkunde, the 48-month case series demonstrated a significant reduction in mean IOP as compared to baseline, along with a significant decrease in the mean number of glaucoma medications, following canaloplasty performed with the company’s proprietary iTrack device. An internationally renowned glaucoma surgeon and one of the pioneers of the canaloplasty procedure, Prof Koerber has been using the iTrack device in clinical practice for nearly two decades.
performed as a standalone procedure (n=4) or in conjunction with cataract surgery (n=23), canaloplasty demonstrated a sustained reduction in IOP and in medication burden four years after surgery
Together, these publications raise awareness of canaloplasty, a procedure that acts on all aspects of the conventional outflow system (trabecular meshwork, Schlemm’s canal and collector channels) and its role in the glaucoma treatment paradigm.
Forty-four (44) eyes of 44 patients were included in the Gallardo study. Twenty-three (23) eyes underwent iTrack as a standalone procedure (iTrack-alone group) and 21 eyes iTrack in combination with cataract surgery (iTrack+phaco group). There was a statistically significant reduction in IOP and number of medications between baseline and all post-operative visits (p<0.0001) either when canaloplasty was performed as a standalone procedure or in combination with cataract surgery (Table one).
Table 1. Thirty-six-month results of eyes treated with iTrack alone, iTrack combined with phacoemulsification, and all eyes considered together (Gallardo, 2022).
The study by Prof Koerber corroborated the findings of Dr Gallardo, demonstrating that the comparable reduction in IOP and medications is sustained 48 months postoperatively. Indeed, performed as a standalone procedure (n=4) or in conjunction with cataract surgery (n=23), canaloplasty demonstrated a sustained reduction in IOP and in medication burden four years after surgery (Table two).
Table 2. Fourty-eight-month results of all eyes considered together (Koerber & Ondrejka, 2022).
In Prof Koerber’s cohort, approximately half of the eyes in the case series (n=13) were defined as controlled with medications at baseline, with an IOP equal to or less than 18 mmHg. In these eyes, canaloplasty was performed to reduce patient reliance on medications due to intolerance or non-compliance, while maintaining IOP within target range. The mean number of medications for this group was 1.77 ±0.93 at baseline and reduced by more than 50% to 0.83 ±0.98 at 48 months. In addition, 50% of these eyes were on zero medications at the 48-month follow-up.
Led by Dr Kamran Riaz, a corneal specialist from the Dean McGee Eye Institute, University of Oklahoma, USA, and Dr. Mahmoud A. Khaimi, a novel study on canaloplasty performed in 17 eyes post-keratoplasty has shed new light on the safety profile of the procedure in patients with fragile corneas. Published in the March 2022 issue of Cornea, this case series demonstrated that canaloplasty performed via an ab-interno surgical technique effectively reduced IOP and maintained graft survivability in post-keratoplasty eyes for at least 12 months. The reduction in IOP observed in post-keratoplasty eyes is consistent with the results in non-keratoplasty eyes, as per the published literature. While a variety of MIGS procedures may be considered in post-keratoplasty patients, the study demonstrated that canaloplasty is associated with a low risk of complications in this unique and challenging patient population.
The frequency of surgical and post-surgical complications reported was low in all studies, with no serious adverse events recorded.
According to Dr Gallardo, canaloplasty is typically one of his first treatment choices because it rejuvenates the natural outflow system while preserving the eye tissue for subsequent treatments. “When it comes to treating mild-moderate glaucoma patients, my preference is to first manipulate the patient’s natural system to its maximum potential. Canaloplasty allows me to do this. Rather than bypass diseased parts of the outflow system, or remove disease tissue, canaloplasty combines a mechanical process of microcatheterisation, followed by the delivery of high-molecular weight viscoelastic via a process described as viscodilation, to improve the overall patency and structure of the system, improving outflow facility. It also removes physical blockages within the outflow pathway. In short, it aims to get the patient’s natural system working again and, in most of my patients, it has proven to be a highly effective option over the long-term.”
According to Prof Koerber, canaloplasty via an ab-interno surgical technique offers utility in the earlier stages of the glaucoma disease process in reducing patient reliance on medications. “Glaucoma medications are associated with compliance issues. Canaloplasty is an ideal procedure as it mediates medication reduction with minimal risk and does not preclude future surgical approaches. It is a procedure that is safe and easily combined with other interventions, which is why there is growing interest in the procedure among cataract surgeons and other ophthalmologists, in addition to glaucoma surgeons,” commented Prof Koerber.
According to Dr Riaz, performing surgery for glaucoma in a patient with a compromised cornea requires a delicate balance: there is a need to safely and effectively reduce the IOP without impacting the health of the cornea.
“The optimal glaucoma procedure for patients with corneal disease or previous corneal surgery is one that effectively lowers IOP without causing unwanted inflammation, corneal damage, and corneal decompensation. With canaloplasty we can effectively improve physiologic outflow rather than opening up one or more isolated points of drainage that might create a potentially damaging preferential outflow pathway. Additionally, no device is left behind in the eye, so there is nothing to touch and mechanically damage the cornea during or after the procedure. Based on my experience, canaloplasty with iTrack can be safely performed in patients with corneal disease and even previous PK.”
References
- Gallardo MJ. 36-month effectiveness of ab-interno canaloplasty standalone versus combined with cataract surgery for the treatment of open-angle glaucoma. Ophthalmol Glaucoma. 2022 Feb 17:S2589-4196(22)00025-4. doi: 10.1016/j.ogla.2022.02.007. Epub ahead of print. PMID: 35183815. pubmed.ncbi.nlm.nih.gov/35183815/
- Koerber N, Ondrejka S. Four-Year Efficacy and Safety of iTrack Ab-interno Canaloplasty as a Standalone Procedure and Combined with Cataract Surgery in Open-Angle Glaucoma. Klin Monbl Augenheilkd. 2022 Apr 14. English. doi: 10.1055/a-1737-4149. Epub ahead of print. PMID: 35426107. pubmed.ncbi.nlm.nih.gov/35426107/
- Riaz KM, Gill MS, Murphy DA, Ding K, Khaimi MA. Surgical Management of Intraocular Pressure With Ab Interno Canaloplasty in Postkeratoplasty Patients: 12-Month Results. Cornea. 2022 Mar 5. doi: 10.1097/ICO.0000000000003009. Epub ahead of print. PMID: 35249980. pubmed.ncbi.nlm.nih.gov/35249980/
