Laird Harrison

March 04, 2015

CORONADO, California — Trabecular micro-bypass stents reduce intraocular pressure in glaucoma patients just as well as the prostaglandin analog travoprost, according to a new study.

Although hypotension medication helps many people with open-angle glaucoma, some can't tolerate it or have trouble adhering to their prescriptions. These patients might benefit from micro-invasive glaucoma surgery using stents, said investigator Steven Vold, MD, who has an ophthalmology practice in Fayetteville, Arkansas.

"It's not unusual for me to get these patients off medicine, and they're just ecstatic with the results," Dr Vold told Medscape Medical News.

He presented the study results here at the American Glaucoma Society 2015 Annual Meeting.

The implantation of a single trabecular micro-bypass stent has been approved by the US Food and Drug Administration, but only in combination with cataract surgery. In their study, Dr Vold and his colleagues implanted two such stents (iStent, Glaukos) without any cataract procedure.

To evaluate how well the stents compare with medication, the team randomly assigned 50 eyes to stents and 48 eyes to travoprost.

All eyes had untreated open-angle glaucoma, pseudoexfoliative glaucoma, or high-risk ocular hypertension. Intraocular pressure ranged from 21 to 40 mm Hg.

In the stent group, two of the single-piece L-shaped titanium stents were implanted in each eye. The stents are inserted through the trabecular meshwork into Schlemm's canal, improving aqueous outflow, Dr Vold explained.

The decrease in intraocular pressure was greater in the stent group than in the travoprost group over the 2-year study period.

Table. Intraocular Pressure Over Time

Mean Intraocular Pressure Stent Group (mm Hg) Travoprost Group (mm Hg)
Baseline 27.7 25.0
1 year 13.8 13.9
2 years 13.9 15.0

 

There were no complications from the surgery.

During the study period, four eyes in the stent group and two in the travoprost group lost some best-corrected vision associated with cataract progression, and one eye in each group underwent cataract surgery.

At 2 years, five patients in the stent group and seven in the travoprost group required additional medication.

The decrease in intraocular pressure in the travoprost group was greater than expected. The researchers attribute this to some combination of regression to the mean, initial treatment in naïve eyes, and high compliance.

This study could encourage insurance companies to cover the use of stents, said Shuchi Patel, MD, from Loyola University in Chicago.

"This is showing that even offering surgery as a first-line treatment may be reasonable," she told Medscape Medical News.

Dr Vold reports consulting for Glaukos, the maker of the iStent, and for AEON, Alcon, Allergan, AqueSys, Bausch & Lomb, Calhoun Vision, Carl Zeiss Meditec, ForSight Labs, InnFocus, IOP, IRIDEX, Ivantis, NeoMedix, Ocular Therapeutix, Ocunetics, QLT, Solx, Transcent Medical, and TruVision Systems. Dr Patel has disclosed no relevant financial relationships.

American Glaucoma Society (AGS) 2015 Annual Meeting: Abstract 39. Presented February 26, 2015.

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