Long Term Outcomes Of An Updated Design For A Novel Cilio-Scleral Interposition Device: Enhancing Outflow Without Entering The Anterior Chamber

To assess the long-term safety and efficacy of an updated design of a novel cilio-scleral interposition device (CID) inserted ab externo, without subconjunctival filtration, nor penetrating the anterior chamber, on IOP and postoperative glaucoma medication burden of patients with primary open-angle glaucoma (POAG) and primary angle closure glaucoma (PACG).

Interim analysis at twenty-four months postoperative for a prospective, nonrandomized single-center clinical trial (NCT05236439) conducted in S.V. Malayan eye Centre, Yerevan, Armenia, recruited in between June and December 2022, with follow up planned to three years.

A single CID SV22 implant, a 26% hydrophilic acrylic, 7mm x 3.4mm plate was inserted 2 mm behind the surgical limbus through 2 scleral incisions, separating sclera and ciliary body, without entering the AC. The updated design features new dimensions, corrugations, and a conjunctival-preserving surgical technique. Incisions were sutured to avoid bleb formation. Inclusion criteria included POAG or PACG (Shaffer grade 1-4) uncontrolled on 1 to 4 ocular hypotensives, no prior glaucoma laser (except peripheral iridotomy) or intraocular surgery. Ocular hypotensives were stopped on the day of surgery, with non-steroidal anti-inflammatories prescribed routinely postoperatively. IOP, medication and safety outcomes were collected to Month 24.

A total of 58 Caucasian patients were enrolled in the study, evenly split at baseline with POAG and PACG, aged 64.0 ± 10.9 years (24 Male, 33 Female). Thirty-six patients were included in the intent-to-treat interim analysis at twenty-four months (M24) postoperative. At baseline, mean medicated IOP was 23.46 ± 1.74 mmHg with mean medication burden of 1.9 ± 0.9 agents. At M24, mean IOP was 13.78± 3.17mmHg, showing a decrease of 9.7 mmHg from baseline. Mean medication burden at M24 was 0.4 ± 0.7 agents, demonstrating a decrease of 1.5 medications from baseline. No serious adverse device-related events, no fibrotic reaction surrounding CID, nor secondary surgical interventions were reported.

These data build upon already available long-term safety and efficacy data from prior CID trials, which used earlier CID device designs. The updated design demonstrates sustained improvement in a refined surgical technique. Data to M24 provides evidence that CID can lower IOP and postoperative medication burden in POAG and PACG, without penetrating the AC, and preserving conjunctiva. The AC-free surgical technique may improve patient safety, with limited AC inflammation and a limited postoperative treatment course. CID could represent a safe and effective treatment option to be considered for patients with POAG and PACG uncontrolled on medical treatment, before filtering surgery.