Study Compares Collagen Implantation Techniques

Iranian doctor, Farhad Nejat, examines a patient’s eye at the Helal Iran Eye Clinic during the World Glaucoma Week in Tehran on March 11, 2015. Screenings free of charge are offered to patients on this day to help raise awareness amongst the public and encourage people to get examined. Glaucoma is the second largest cause of blindness worldwide. AFP PHOTO / BEHROUZ MEHRI (Photo credit should read BEHROUZ MEHRI/AFP via Getty Images)
The deep sclerectomy with a suprachoroidal implant may have advantages.

In deep sclerectomy, a nonpenetrating filtration surgery, a somewhat new method involves placing a collagen implant into the eye’s suprachoroidal pocket instead of the traditional placement within the sclera. An investigation published in the Journal of Glaucoma compares the long-term outcomes of the 2 techniques.

The study shows that suprachoroidal collagen implants (DSSCI) reduced mean preoperative intraocular pressure (IOP) significantly at the 60-week mark (from 25.3 mm Hg ± 5.3 mm Hg to 9.8 ± 3.7 mm Hg). In the same period, intrascleral collagen implants (DSCI) also reduced participants’ mean IOP (from 24.1 mm Hg ± 4.2 mm Hg to 14.8 mm Hg ± 4.0 mm Hg). The researchers report that the safety of both techniques is similar — the number of adjunctive procedures needed after surgery was relatively the same between participants who underwent DSSCI and DSCI (P =.01), according to the researchers. They also noted that a safety advantage of DSSCI is its stability, as it has no need for a suture.

The number of medications taken by participants who received the suprachoroidal implant dropped as well (from 2.4 ± 0.5 before surgery to 0.2 ±0.1 after 60 months). It was also reduced for those whose implants were placed intrasclerally, (from 2.7 ± 0.4 to 0.3 ± 0.2, P =.001). “Another possible advantage of [DSSCI] is not having to place a device in the anterior chamber, potentially avoiding corneal endothelial loss,” the study says. 

The suprachoroidal pathway may expand drainage of aqueous, according to investigators. Alternately, with the suprachoroidal technique, about a third of the porcine collagen implant extends into the intrascleral layer, and may potentially hold a space in both structures until collagen is absorbed.

The prospective trial took place at Geneva University Hospitals in Geneva, Switzerland. Participants included 13 patients (26 phakic eyes) age 25 years or older, with medically uncontrolled primary or secondary open-angle glaucoma. Subjects were randomly assigned to undergo deep sclerectomy with a collagen implant placed intrasclerally in 1 eye, and suprachoroidally in the other.

Researchers defined complete success as maintenance of IOP of 21 mm Hg or lower at 60 months without hypotensive therapy, and qualified success as maintaining this IOP level with or without supplemental therapy. The success rate for suprachoroidally placed implants was 84.6%, and for intrascleral implants it was 76.9%. Qualified success reached 92.3% for those with suprachoroidal implants, and 84.6% in the intrascleral group. In addition, at month 60, best corrected visual acuity was similar between the 2 types ( DSSCI was 0.80 ±0.17, and DSCI was 0.82 ± 0.17, P =.004).

Neither method resulted in perforation of the trabeculo-Descemet membrane (TDM). Nine of the total subjects developed a cataract, and 9 eyes needed a 5-fluorouracil subconjunctival injection for potential bleb failure. Six in each group underwent YAG laser goniopuncture at 13 months to 15 months due to nonpercolating TDM detected with gonioscopy. No implant in either group migrated. Researchers suggest cellular filtration and fibrosis in the suprachoroidal space may limit DSSCI’s success long term, but conclude the method is safe and effective to lower IOP.


Mitwally R, Aref A, Shaarawy T. Deep sclerectomy with intrascleral versus suprachoroidal collagen implant: a randomized control trial. J Glaucoma. 2021;30(2):124-128. doi:10.1097/IJG.0000000000001703.