Inter-eye relationship of intraocular pressure change after unilateral trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation

PURPOSE: This study assesses short-term intraocular pressure (IOP) change in the fellow eye of glaucoma patients after mitomycin C–augmented trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation in the treated eye. MATERIALS AND METHODS: Retrospective chart review of 235 glaucoma patients (235 eyes) was performed. Patients underwent initial trabeculectomy (187 patients), filtering canaloplasty (25 patients), or PreserFlo™ microshunt implantation (23 patients) in one eye, while the fellow eye was naïve to any previous glaucoma surgery. IOP was evaluated before and on the 1st and 2nd days and at 1 week after surgery. Main outcome measure was IOP change in the fellow eye. Secondary outcomes were proportion of clinically significant IOP elevation in the fellow eye and evaluation of potential risk factors associated with postoperative IOP fluctuation. RESULTS: IOP in the fellow eye at 1 week after trabeculectomy was statistically significantly lower than preoperatively (p < 0.0001), while the IOP did not change significantly in the fellow eyes in filtering canaloplasty or PreserFlo groups. The higher the preoperative IOP was in the fellow eye, the larger was the intraocular pressure-lowering effect at 1 week after trabeculectomy (p < 0.0001). A clinically significant IOP elevation was noted in 14.2%, 9.5%, and 5% of fellow eyes after trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation, respectively. CONCLUSIONS: This study shows an IOP-lowering effect in the fellow eye of glaucoma patients after trabeculectomy. Significant IOP rise might occur in the fellow eye of some glaucoma patients after different types of glaucoma surgery. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00417-021-05188-y.