Graham A. Lee, Ashish Agar, Mark Y. M. Chiang, Brendan Cronin, Matthew D. Green

Purpose: The purpose of this study was to assess five-year outcomes in patients who underwent cataract surgery alone (CS) compared to those who underwent
cataract surgery combined with a Hydrus® Micro-stent (HS).

Methods: Subjects with primary open angle glaucoma and visually significant cataract with washed-out diurnal intraocular pressure (IOP) 22 – 34 mmHg were randomised 2:1 to undergo CS or HS in the HORIZON study.

Results: At five years, the mean IOP reduction was greater in the HS group vs CS -8.3% ± 3.8% vs. -6.5% ± 4.0% (p < 0.001). The proportion of eyes requiring medications was significantly lower in the HS group (34% vs. 64%, p < 0.001). Among eyes that were medication free, the mean unmedicated IOP was unchanged from the pivotal two year report (16.6 vs. 16.6 HS group and 17.6 vs. 17.4 CS group). There were no significant changes in BCVA or other adverse events compared the original pivotal two year report. Conclusion: Hydrus combined with phacoemulsification results in sustained IOP and medication reduction from year 2 to year 5. The treatment arm showed a significant reduction in secondary incisional glaucoma surgery (trabeculectomy or tube shunt). Mean annual endothelial cell density declined in both groups within the range of normal ageing. There were no significant changes in safety findings from two years.