5-Year Safety And Effectiveness Of Phacoemulsification Combined With A Schlemm’S Canal Microstent: Results From The Horizon Trial

Several microinvasive glaucoma surgery (MIGS) techniques combined with cataract surgery have been shown to reduce IOP and medication use postoperatively from 6 months to 2 years in randomized clinical trials. The purpose of this study is to assess 5-year outcomes in patients who underwent cataract surgery combined with implantation of a Hydrus Microstent compared to cataract surgery alone.

Tertiary specialist cataract and glaucoma surgery centersparticipating in a multicenter, prospective, randomized clinical trial.

Subjects with mild to moderate primary open angle glaucoma (POAG) and visually significant cataract and washed-out diurnal IOP 22 - 34 mmHg were included in the study. After successful cataract surgery, pateints were randomized 2:1 to treatment with the Hydrus Microstent (HS) or cataract surgery alone (CS) . Scheduled follow up visits included comprehensive ocular examinations, gonioscopy, and spectral microscopy of the corneal endothelial cell layer were conducted through 5 years postoperative.  

556 eyes were randomized to HS (N=369) or CS (N=187). Baseline characteristics were equivalent. 5-year follow up was completed in 444/556 (80%) eyes. The proportion of medication free eyes was significantly higher in HS (66% vs. 46%, p<0.001). There was a significant reduction in the frequency of further incisional glaucoma surgery (trabeculectomy, tube shunt, or cyclodestructive procedures) at 5 years in the HS group (2.5% vs. 6.4%, log-rank p=0.022). 5 year mean ECD was 1967 ± 522 (HS) and 2117 ± 442 (CS). There were no significant differences in visual acuity or adverse findings.

Combined phacoemulsification with the Hydrus Microstent is safe and effective through 5-years of follow up. Specular microscopy demonstrated comparable rates of corneal endothelial cell loss between study groups. Treatment with the microstent significantly reduced medication use throughout the study period and resulted in a significant reduction in the number of further glaucoma surgeries.