Use of minimally invasive glaucoma surgery (MIGS)—including trabecular bypass, suprachoroidal outflow, subconjunctival drainage, and aqueous production-reducing procedures—more than doubled from 2013 through 2018 in the USA, despite limited evidence of their long-term safety or effectiveness.
Over the same period, standard glaucoma procedure volume—including trabeculectomy and glaucoma drainage devices (GDD)—declined by a smaller amount, reported Shuang-An Yang MD, MPH at the Association for Research in Vision and Ophthalmology 2021 Annual Meeting.
The findings highlight the need for trials comparing the safety and outcomes of novel MIGS with traditional glaucoma treatments known to be sight-saving, said Dr Yang, who is an ophthalmology research fellow from Taiwan at the Harvard TH Chan School of Public Health and the Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA.
IRIS STUDY
The study is based on a review of 510,577 MIGS and standard glaucoma procedures recorded in the American Academy of Ophthalmology’s Intelligent Research in Sight (IRIS) database. During the six years examined, annual adjusted volume of MIGS procedures more than doubled, from 31,059 to 69,420. iStent (Glaukos) use grew most, from 14% to 40% of all glaucoma procedures. Traditional glaucoma surgeries declined from 46,385 to 22,347 annually over the same period.
About 10% of 203,332 eyes with a glaucoma diagnosis underwent multiple glaucoma procedures, with about 36% on the same day and 64% on subsequent days. iStent and endoscopic cyclophotocoagulation (ECP) were the most common concurrent procedures, accounting for 55%. Trabeculectomy and GDD were most often followed by another standard glaucoma surgery, but when followed by MIGS, ECP, and goniotomy were most common. Nearly two-thirds of eyes underwent concurrent phacoemulsification.
Significant demographic differences among procedure types also were found. Females were more likely to receive iStent or ECP, while younger males were more likely to receive GDDs. Whites were more likely to receive iStent or Xen Gel Stent (Allergan), while Blacks more often received GDD, goniotomy, or trabeculectomy.
The trend towards MIGS is driven by the desire for intraocular pressure-lowering procedures that are less risky and uncomfortable for patients, Dr Yang said. During the study period more MIGS procedures were approved, and they are easy to combine with phaco. Changes in the USA’s Medicare insurance programme discouraging traditional glaucoma surgery may also be a factor.
Still, research is needed to better understand MIGS outcomes and guide their use, Dr Yang said.
“It is unclear whether MIGS can replace trabeculectomy as sight-saving surgery, and whether the expense of MIGS can be justified by their effectiveness, longevity, and safety.”
Shuang-An Yang: christine108801@gmail.com
