Sidebar: My Experience With a Trabeculotome
The Trab360 (SightSciences) is a trabeculotome, a nonpowered instrument for manually cutting the trabecular meshwork. I use the Trab360 in patients with angle recession, juvenile open-angle glaucoma, or pigment dispersion and for individuals seeking a purely internal option to enhance physiologic outflow (ie, not a bleb-forming procedure). Patients must be able to tolerate medications, which may be required to achieve lower IOP targets, since IOP reduction will ultimately be limited by episcleral venous pressure.
Here are a few tips based on my experience with the Trab360.
First, selecting and counseling patients are key. Do not expect dramatic IOP reductions if the distal outflow pathway is not working well (and you do not know that going in).
Second, the trabecular meshwork (TM) should be incised with the tip of the device. Sometimes, angling the tip upward will make incising the TM easier. I find it helps to cut an opening in the TM and then to back up just enough to allow for the cutting filament to enter Schlemm canal.
Third, the device has a limit to how much the wheel is dialed (Figure). The total excursion of the filament is about 180º. Once deployed, the filament is retracted back into the device and can be used one more time for a total of 360º of potential treatment. Each time the wheel is turned, there are palpable “clicks.” Do not dial past a “click” unless you are sure you are in the canal, because the device unfortunately measures how much total excursion has occurred. It will not deploy more than about 360º.
Fourth, if performing this as a solo procedure, make the wound just anterior onto cornea.
Fifth, I received a referral for a patient with a small cleft and pupillary abnormality after the procedure. Slightly directing the tip upward as the filament advances can prevent iris root trauma.
Arsham Sheybani, MD, is an assistant professor, ophthalmology and visual sciences, at Washington University School of Medicine in St. Louis, Missouri. He acknowledged no financial interest in the product or company mentioned hererin. Dr. Sheybani may be reached at email@example.com.