Efficacy and Safety of a Releasable Intraluminal Suture Technique to Reduce Hypotony Following Glaucoma Surgery Using the Preserflo Device

Overview

Glaucoma is a common and irreversible disease of the optic nerve. It is the second leading cause of blindness worldwide. Glaucoma can be treated with medication, laser therapy, or surgery; the latter is often necessary. Traditional surgeries are invasive and carry a high rate of complications (hypotony, endophthalmitis, cataracts, etc.). Consequently, several types of micro-invasive surgeries (MIGS) and less invasive but effective surgeries, LIGS, have been developed to reduce surgical risks while maintaining effectiveness in lowering intraocular pressure (IOP). PRESERFLO is a drainage system less than 1 mm thick that regulates the outflow of aqueous humor from the eye. It is made of a soft, flexible biomaterial that conforms to the curvature of the eye. This biomaterial does not trigger a negative immune response. PRESERFLO is an example of a recently developed, powerful LIGS procedure (with preliminary results demonstrating efficacy and safety). PRESERFLO is already in use in France (marketing authorization and CE marking obtained) and is covered by social security. This technique is highly effective in lowering IOP, but it may be associated with hypotony, although less frequently than with trabeculectomy. The use of a releasable suture placed inside the Preserflo to limit drainage and, consequently, reduce the risk of hypotony has been described with good results in preliminary studies. Nevertheless, it is necessary to evaluate the efficacy and safety of this technical modification in a randomized, prospective clinical trial to better understand whether this modification is beneficial for improving the treatment of patients with glaucoma.

Interventions

• Procedure Classical surgery
  After peritomy, coagulation, and the application of 0.04% mitomycin C (as in a trabeculectomy or any filtration surgery), a scleral tunnel is created 3 mm from the limbus using a 1-mm scalpel designed for this purpose, followed by a 25G needle, which is inserted into the eye parallel to the iris. Next, the Preserflo is inserted into this tunnel, away from the cornea and the iris. The outflow of aqueous humor through the Preserflo is tested by injecting BSS into the anterior chamber. The peritomy
• Procedure Intraluminal suture
  A 9-0 Ethilon suture is inserted into the distal end of the Preserflo to partially occlude the outflow of aqueous humor through this drain, thereby reducing the risk of postoperative hypotony. The other end of this suture is attached to the cornea, forming a loop (which will allow it to be removed later). Next, the Preserflo and the suture are covered with the Tenon's capsule and the conjunctiva, as in the standard technique.

Primary outcome measures

• Postoperative hypotonia [Time frame: 12 months after surgery]

Secondary outcome measures (1)

• Complete surgical success [Time frame: 12 months after surgery]

Eligibility criteria

Inclusion criteria

• Primary open-angle glaucoma, pseudoexfoliative glaucoma or pigmentary glaucoma with an indication for glaucoma surgery (defined as uncontrolled intraocular pressure or worsening of visual fields, despite maximum tolerated medical therapy) and an open iridocorneal angle (trabeculum visible on gonioscopy, Shaffer classification grade 3-4)

• Healthy, mobile conjunctiva (without scarring or adhesions).
• The indication for glaucoma surgery is defined as uncontrolled IOP or worsening of visual fields despite maximum tolerated medical therapy, and with either a previous failure of trabeculectomy or a risk of failure.
• Maximum tolerated medical therapy: 3 or more classes of ocular hypotensive treatment, or fewer if there is an allergy or intolerance to the treatment. Visual field defects must be more severe than -3 dB in mean deviation.

Exclusion criteria

• severe systemic pathologies
• other ophtalmic pathologies (except cataract)
• previous intraocular surgery (except cataract)
• neovascular glaucoma or iris neovascularization
• pachymetry < 490µm or > 620µm
• contraindication to PRESERFLO Microshunt

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Identifiers

NCT: NCT07531199 · 2025-26-PDB

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗