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SPOTLIGHT ON TECHNOLOGY & TECHNIQUE

A new MIGS, thanks to users of Visco, Trab 360

At first glance, the MIGS marketplace may seem like it’s getting crowded. But look closer and you will notice that the products and procedures can be separated into two camps: implants and nonimplants. The Omni Surgical System, says Shawn O’Neil, senior vice president, sales and marketing for Sight Sciences, combines 360-degree canaloplasty with 360-degree trabeculotomy in one instrument. It does not leave an implant behind yet appears a bit more invasive than other types of MIGS. It does, however satisfy the hallmark parameters of MIGS: an ab interno, micro-incisional approach, minimal disruption to the ocular anatomy, reliable IOP lowering and rapid postoperative visual recovery.1

The Omni received FDA approval in January and became commercially available in late February.2 It combines the technology of Sight Sciences’ original Visco 360 and Trab 360 systems into one disposable unit. Nathan Radcliffe, MD, Microincisional Surgery Center of Excellence, New York Eye and Ear Infirmary , says the Omni is a remarkable feat of engineering and manufacturing, with controllable wheels and predetermined amounts of viscoelastic in canisters.

Mr. O’Neil says the Omni is the brainchild of users of the Visco 360 and Trab 360. “The idea actually came from our customers. They [wanted] to have an efficient, effective way to perform both of these procedures in a single handpiece.”

Which likely explains Dr. Radcliffe’s take on the Omni’s learning curve.

“I found that the skills I had acquired using the Visco 360 and Trab 360 were perfectly suitable for Omni. Learning Visco 360 or Trab 360 for a MIGS surgeon is very achievable, although it is necessary to be very comfortable with visualization, and the surgery is generally speaking a ‘next step’ in terms of MIGS surgical skills because you are really performing canal surgery rather than just placing a stent in a target tissue.”

According to the Sight Sciences’ website, the procedure requires no sutures; is designed to treat the trabecular meshwork, Schlemm’s canal and the distal collector channels; and can be installed either on its own or in tandem with cataract surgery.

THE PROCEDURE

The surgeon inserts the instrument into the anterior chamber through a clear corneal incision. Using gonioscopy for visualization, the surgeon pierces the trabecular network with the cannula to enter Schlemm’s canal, then uses the manual wheel on the device’s handle to advance the microcatheter through 180 degrees of Schlemm’s canal. Upon retraction of the microcatheter, viscoelastic is automatically released into the transluminal canal and collector channels. The surgeon then removes the cannula from the eye to flip it over, reinserts the device through the clear corneal incision, and performs the same procedure on the opposite 180 degrees of Schlemm’s canal. After completing the second 180 degrees of viscodilation, the surgeon advances the microcatheter again through the same 180 degrees of Schlemm’s canal, but rather than retracting it back into the instrument, the surgeon pulls the microcatheter away from the angle towards the pupil, cutting through the trabecular meshwork, thereby creating a transluminal trabeculotomy.

The instrument is retracted through the corneal incision, rotated 180 degrees and reinserted; the procedure is then repeated for the remaining 180 degrees of the eye.3

Trabeculotomy with canaloplasty restores and maximizes the physiological aqueous outflow by targeting all three potential points of resistance in the conventional outflow pathway.4

Using this tool is efficient, says Dr. Radcliffe. The larger canal size after canaloplasty facilitated recannulation of the canal for the trabeculotomy portion of the procedure. “I found less reflux bleeding with Omni than I had seen with Trab 360. In terms of short-term outcomes, I have seen excellent IOP lowering, perhaps slightly lower IOPs than with Visco 360, and no significant hyphema in the first week.”

Sight Sciences says the Omni is capable of such restoration. It has been theorized that canaloplasty also creates microperforations in the trabecular meshwork to further aid aqueous outflow.5 OM

Dr. Radcliffe, editor of Glaucoma Physician, is a consultant for Sight Sciences.

REFERENCES

  1. Saheb H, Ahmed, II. Micro-invasive glaucoma surgery: current perspectives and future directions. Curr Opin Ophthalmol 2012;23:96-104.
  2. Cision PR Newswire https://www.prnewswire.com/news-releases/sight-sciences-expands-surgical-portfolio-with-fda-clearance-of-the-omni-surgical-system-300577679.html . Accessed Feb. 17, 2018.
  3. Sight Sciences OMNI 720. http://sightsciences.com/ous/products/omni/ . Accessed Feb. 17, 2018.
  4. Körber, N. (2014). Chapter 1: Clinical efficacy and long-term data of canaloplasty, Canaloplasty: it’s all about outflow (pp. 6-4). Cologne, Germany: Ellex Medical Pty Ltd. E&OE.
  5. Fox AR, Risma TB, Kam JP, Bettis DI. MIGS: Minimally Invasive Glaucoma Surgery. https://webeye.ophth.uiowa.edu/eyeforum/tutorials/migs/ . September 27, 2017. Accessed Feb. 17, 2018.