The application of polyvinylpyrrolidone collagen (PVP) during trabeculectomy achieves a significant drop in intraocular pressure (IOP) and medication needed from baseline to 36 months, researchers report. The technique also resulted in a lower incidence of adverse events than mitomycin C (MMC), for patients with primary open-angle glaucoma (POAG).

The researchers sought to report the long-term outcomes of PVP to find an alternative to MMC for patients undergoing the procedure since MMC is associated with hypotony, avascular blebs, and other adverse events.

The researchers included 26 eyes of 26 patients  with POAG in the study and randomly assigned them to either the PVP group or the MMC group. To determine baseline IOP, patients were discontinued from all ocular hypotensive treatment for the month preceding an eye exam and the trabeculectomy.

The investigators performed 2 paired t-tests to measure mean IOP and mean number of medications at baseline and at 36 months follow-up for each group. Differences between the 2 groups were assessed using a 2-sample t-test with Satterthwaite’s approximation for unequal variances.

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Eyes treated with PVP showed a lower rate of complications than the eyes in the MMC group. The most common complication in both groups was transient flat anterior chamber (6 patients in the MMC group and 3 in the PVP group), followed by early hypotony (5 eyes in the MMC group and 2 in the PVP group). The PVP group did not present choroidal detachment while 2 eyes in the MMC group had serous posterior choroidal detachment during the first week postoperative. In the MMC group, 3 eyes presented early wound leak in the first 2 weeks after the surgery, as did 1 eye in the PVP group.

IOP underwent a statistically significant reduction from baseline to 36-month follow-up by 7.6 mm Hg in the MMC group and 8.2 mm Hg in the PVP group (both P <.0001). The mean change in number of medications from baseline to 36 months was -0.9 medications (P <.05, P =.02) for the MMC group and -1 medication (P <.05, P =.006) in the PVP group. The differences between the groups’ reductions in number of medications and IOP were not statistically significant.

“The lower rate of flat anterior chamber, hypotony and choroidal detachment in the PVP group, as well as the fact that this group showed no added or new complications is an encouraging prospect to continue exploring its use as an antifibrotic in glaucoma incisional surgery,” the study says.

The study was limited in that it reviewed a small number of patients.


Gil-Carrasco F, Alvarez-Ascencio D, Tolosa-Tort P, et al. Outcomes of trabeculectomy with polyvinylpyrrolidone collagen versus mitomycin in primary open angle glaucoma. 36-month follow-up. Arch Soc Esp Oftalmol. Published online December 17, 2020. doi:10.1016/j.oftale.2020.09.007