At 1 year, the PreserFlo MicroShunt with mitomycin-C glaucoma can have a 68.3% success rate, according to the findings of a real-world, multicentre investigation. The study’s results show a 37% reduction in IOP, a 79% reduction in the need for glaucoma medications, and a good safety profile, the British Journal of Ophthalmology study reports

The investigation was conducted across 3 tertiary referral centers in the UK between 2019 and 2020. Patients (N=104) who received the PreserFlo MicroShunt device with intraoperative mitomycin-C were evaluated for outcomes at 1 year. Complete success was defined as intraocular pressures (IOP) between 6 mm Hg and 21 mm Hg, and at least a 20% reduction from baseline without the need for medication. It also qualified success as the same endpoints, but with medication use.

Patients were aged mean 68.9 (range, 60-81) years, 50.9% were women, 56.7% were White, 66.6% had an affected left eye, IOP was 23.6 (range, 14-50) mmHg, best corrected visual acuity (BCVA) was 0.3 (range, −0.2 to 2.0) logMAR, patients were taking 3.0 (range, 0-5) medication classes, and 66.3% of eyes had undergone previous surgery.

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At 1 year, 51.9% of eyes had complete success and 16.4% qualified success. The reason for failure (31.7%) was due to insufficient IOP improvement from baseline (23.1%), elevated IOP (13.5%), and need for glaucoma reoperation (13.5%). No failures occurred due to loss of light perception or vision loss.

The only factor that increased risk for device failure was high preoperative mean deviation (hazard ratio [HR], 1.055; 95% CI, 1.0075-1.11; P =.0227).

The most common complications during the first three months were hypotony (19.2%), clinical hypotony with sequelae (11.5%), and choroidal detachment (10.6%). A total of four complications occurred after three months, which were hypotony, clinical hypotony with sequelae, microshunt exposure, and cystoid macular edema.

The most common postoperative interventions were subconjunctival injection (44.2%), 5-fluorouracil injection (33.7%), repeated subconjunctival injections (24.0%), dexamethasone/betamethasone injection (23.1%), needling (12.5%), and combined 5-fluorouracil and steroid injection (11.5%).

Reoperations were required by three patients during the first three months and 14 after three months. Indications for reoperations included bleb revision for high IOP (n=9), bleb revision for leak (n=3), phacoemulsification (n=2), bleb revision for exposed tube (n=1), glaucoma drainage device (n=1), and iStent inject (n=1).

This study was limited by the variation in intraoperative mitomycin-C dosing during procedures.


Tanner A, Haddad F, Fajardo-Sanchez J, et al. One-year surgical outcomes of the PreserFlo MicroShunt in glaucoma: a multicentre analysis. Br J Ophthalmol. 2022;bjophthalmol-2021-320631. doi:10.1136/bjophthalmol-2021-320631