Valveless Drainage Device an Option in Refractory Glaucoma

Optic disc affected by glaucoma.
A study supports the implant alone or combined with phacoemulsification.

A new novel valveless glaucoma drainage device (GDD) reduced intraocular pressure (IOP) comparable with other GDDs in patients with refractory glaucoma, according to a study published in the Journal of Glaucoma. The implant was designed with several goals in mind, including a curved and flexible plate to conform to the globe, more anterior scleral fixation suture points than other GDDs to facilitate fixation to the sclera, and a prethreaded 4-0 polypropylene rip cord suture to reduce early postoperative hypotony.

The multicenter retrospective analysis looked at 104 eyes of 100 study participants (63.5% with primary open-angle glaucoma, 62.5% with severe glaucoma) with medically or surgically uncontrolled glaucoma who were implanted with the 250 mm2 or 350 mm2 Ahmed ClearPath (ACP, New World Medical) models. These implantations happened either as a standalone procedure or in combination with other procedures, and were performed by 10 US surgeons. The pre-, intra-, and postoperative data through 6 months were collected. The study reviewed changes to the participants’ IOP as well as the number of medications they used to manage it.

The study reports that the mean baseline IOP was 26.3±9.0 mm Hg, and the mean number of medications taken was 3.9±1.3. Through 6 months of follow-up, mean IOP ranged from 13.6 mm Hg to 16.7 mm Hg and mean medication use ranged from 0.9 to 1.9 medications (P <.0001 at all timepoints for each outcome measure).

Six months after implantation with the ACP, their mean IOPs were approximately 13.7 mm Hg — a roughly 13.0 mm Hg, or 43.0%, reduction (P <.0001). Mean medication use was significantly reduced too, down by 2.1 medications, 04 47.7%, to 1.9 medications per eye (P <.0001).

Researchers report that the most common adverse events were anterior chamber inflammation (16.3%), hyphema (15.4%), hypotony (6.7%), cystoid macular edema (3.8%), limbal wound leak (2.9%), tube erosion (2.9%), and pain (2.9%). However, these were characterized as mild or moderate and resolved without intervention.

The study’s limitations include its short follow-up duration, but based on the limited time that the GDD has been available, this data is still likely useful to clinicians in understanding how it might fit into their practice, researchers report. They also note that the study is retrospective with no control group, which prevents head-to-head comparisons with other GDDs

The investigators say that they “plan to further study this implant and provide longer-term follow up but felt it was essential to demonstrate 6-month safety, which we feel is reflective of this implant’s long-term outcomes.”


Grover D, Kahook M, Seibold L, Singh IP, et al. Clinical outcomes of Ahmed ClearPath implantation in glaucomatous eyes: a novel valveless glaucoma drainage device. J Glaucoma. Published online March 7, 2022. doi:10.1097/IJG.0000000000002013