Effect of unilateral trabeculectomy, filtering canaloplasty or Preserflo^TM MicroShunt implantation on intraocular pressure in the fellow eye

Abstract

Purpose : This study assesses short-term intraocular pressure (IOP) change in the fellow eye of glaucoma patients after Mitomycin C-augmented trabeculectomy (TE), filtering canaloplasty (FCP) or PreserFlo^TM microshunt implantation (PMI) in the treated eye.

Methods : Retrospective chart review of 235 patients (235 eyes) with different types of glaucoma was performed. Patients underwent initial TE (187), FCP (25) or PMI (23) in one eye, while the fellow eye was naïve to any previous glaucoma surgery. IOP was evaluated before and on the 1^st, 2^nd day and at one week after surgery. Study outcomes were IOP change and proportion of clinically significant IOP elevation (postoperative IOP >21 mmHg) in the fellow eye.

Results : The median preoperative and postoperative IOP in the fellow eye on the 1^st day and at one week after TE were 17 (14-20) mmHg, 16 (14-21) mmHg and 14 (12-17) mmHg, respectively. The median IOP change in the operated eyes was -12 (-18 to -7) mmHg and in the fellow eyes -3 (-6 to 0) mmHg at one week after TE (rho=0.24, p=0.001). The median preoperative and postoperative IOP on the 1^st day and at one week after PMI in the fellow eye were 15 (12.5-18) mmHg, 14 (13-16) mmHg and 14 (12-16) mmHg, respectively. The median IOP change in treated eyes at one week after PMI was -9.5 (-14.8 to -6.3) mmHg and -2 (-4 to 1.8) mmHg in fellow eyes (rho=0.82; p<0.0001). IOP in the fellow eye at one week after TE was statistically significantly lower than preoperatively (p<0.0001), while the IOP did not change significantly in fellow eyes in FCP or PMI groups. The higher the preoperative IOP was in the fellow eye, the larger was the IOP-lowering effect at one week after TE (rho=-0.79, p<0.0001) and after PMI (rho=-0.6, p<0.01). A clinically significant IOP elevation was noted in 14.2%, 9.5% and 5% of fellow eyes after TE, FCP or PMI, respectively.

Conclusions : This study shows an IOP lowering effect in the fellow eye of glaucoma patients after TE. The higher the preoperative IOP in the fellow eye of TE and PMI patients, the larger the postoperative IOP lowering effect. The one of the possible mechanisms for IOP change could be central nervous system-mediated reflex.

This is a 2021 ARVO Annual Meeting abstract.

 

Demographic and clinical data of all patients

 

Correlation between preoperative IOP in the fellow eye and IOP change from baseline at 1 week after TE