Registry data finds microstent lowers pressure in patients with primary-open angle glaucoma
Recent reported results
Results achieved with the microstent were presented at the 2019 meeting of the American Academy of Ophthalmology.
In the Horizon Trial, which compared pure phacoemulsification with phacoemulsification and Hydrus Microstent placement and cataract extraction, found that at three years, which is the longest outcome reported with a MIGS device, the microstent enhanced the IOP lowering achieved by cataract surgery alone.
“There was persistent, maintained, greater pressure lowering with the Hydrus device compared with only cataract extraction,” Prof. Gazzard said. “Fewer drops were used and the procedure was seen to be very safe.”
Another noteworthy finding was that the rate of trabeculectomy decreased with the use of the microstent. In the control arm of the trial, 3.9% of patients went on to trabeculectomy because of glaucoma progression compared with 0.6% in the treatment arm, which Prof. Gazzard described as a robust clinical outcome. The endothelial cell count showed a positive result in patients who had completed four years of follow-up.
The full results of the Horizon Trial will be released in the spring of 2020 with more to follow in 2021.
Placing the Hydrus is a safe procedure with low risk of adverse events. Prof. Gazzard reported no problems with chronic inflammation, allergy, obstruction, and uveitis in his patients.
Outside of the U.S., the microstent can be placed in patients with angle closure glaucoma, uveitis, trauma, congenital anomalies, and neovascular glaucoma. In the U.S,. the stent is limited to patients with mild to moderate primary open-angle glaucoma in conjunction with cataract surgery.
“The results provide a glimpse into what the future of MIGS in the US might look like once the indications are expanded. It also speaks to how important following patients is over the long term,” said Dave Van Meter, president and chief executive officer of Ivantis.
Spectrum Registry results
The three-year results reflect the findings of the microstent in more than 900 eyes, in more than 200 of which the microstent was implanted during a stand-alone procedure. These results are likely indicative of what to expect in 2020 from the U.S. results.
The patients in the Australia registry had the full spectrum of glaucoma, ranging from very mild disease that was addressed with the microstent in conjunction with cataract surgery to patients with moderate disease that was refractory to medical therapy who received the microstent as a stand-alone procedure and finally to severe cases for which conventional surgery was unsuccessful and required placement of the microstent during a stand-alone procedure. More than 70% of the eyes completed the three-year follow-up evaluation.
When placed in the eye in conjunction with cataract surgery, the microstent achieved an IOP decrease in excess of 20% with discontinuation of all anti-glaucoma medications.
When positioned during a stand-alone procedure, the microstent achieved in a mean IOP decrease of approximately 30% and all anti-glaucoma medications were discontinued.
The average IOP achieved in all patients was 15 mm Hg or less in both the combination cataract surgery and standalone treatment groups.
Gus Gazzard, FRCOpthMA, MBBCHIR, MD
E: [email protected]
Prof. Gazzard is supported by a grant from the National Institute for Health Research-Health Technology Assessment. He reports that he has no financial interest in any ophthalmic products, company, or related stocks.