Negative Pressure Application by the Ocular Pressure Adjusting Pump to Lower Intraocular Pressure in Normal-Tension Glaucoma: HERCULES Study

Abstract

Purpose: To evaluate the safety and intraocular pressure (IOP)-lowering efficacy of the ocular pressure adjusting pump in subjects with normal-tension glaucoma (NTG).

Design: Prospective, multicenter, masked, randomized, fellow-eye controlled trial.

Subjects, participants, and/or controls: Subjects with NTG with an IOP ≥12 mm Hg and ≤21 mm Hg were enrolled. One eye of each subject was randomized to receive negative pressure application; the fellow eye served as a control.

Methods: Subjects wore the device overnight for 1 year and the applied negative pressure was programmed by subtracting a reference IOP of 6 mm Hg from the baseline IOP.

Main outcome measures: The primary effectiveness endpoint was the proportion of eyes achieving an IOP reduction ≥20% at Week 52 during the day. The secondary endpoint was the proportion of eyes achieving a nocturnal IOP reduction ≥20% at Week 52. Exploratory endpoints included mean IOP reduction in clinic and in the sleep lab.

Results: A total of 186 eyes were randomized across 11 sites. 120 eyes successfully completed all visits across 52 weeks without protocol deviations. At Week 52, 88.3% (n = 53) of study eyes vs 1.7% (n = 1) of control eyes met the primary endpoint. For the secondary endpoint, 96.7% (n = 58) of study eyes vs 5.0% (n = 3) met the endpoint. For exploratory IOP analysis, the mean nocturnal IOP reduction at Week 52 was 8.0 mm Hg (39.1%) from a baseline of 20.4 ± 2.5 mm Hg to 12.4 ± 2.7 mm Hg. There were no serious adverse events. The most commonly reported adverse events were lid (11.8% study, 1.1% control) and periorbital edema (12.9%, 1.1%).

Conclusions: The ocular pressure adjusting pump safely and effectively lowers both daytime and nocturnal IOP in patients with NTG.