Phacoemulsification vs phacoemulsification with micro-bypass stent implantation in primary angle closure and primary angle closure glaucoma: A randomized single-masked clinical study

Abstract

Importance: Primary angle closure glaucoma (PACG) is a major cause of irreversible visual impairment in Asia, but there is no published data on the effect of iStent on these patients.

Background: To compare the efficacy and safety of combined phacoemulsification and iStent implantation with standard phacoemulsification in an Asian population.

Design: A prospective, single-masked, randomized study in a public tertiary eye clinic.

Participants: Patients with concomitant visually significant cataracts and primary angle closure (PAC) or PACG.

Methods: Patients were randomized and underwent either phacoemulsification alone (phaco) or with concurrent iStent injection (phaco-iStent). Demographic and clinical data were collected.

Main outcome measures: Complete and qualified success rates at 12 months were compared between both treatment arms.

Results: Thirty-two patients were recruited between September 2015 and February 2016. All patients completed 12 months of follow-up. There was no statistically significant difference in preoperative IOP (phaco, 17.5 ± 3.1 mmHg; phaco-iStent, 18.6 ± 4.7 mmHg, P = .65) and 12-months postoperative IOP (phaco, 15.0 ± 2.5 mmHg; phaco-iStent, 14.7 ± 3.1 mmHg, P = .86) between both groups. Complete success rates were 43.8% (95% CI, 19.8-65.6) for the Phaco group and 87.5% (95% CI, 58.6-96.7) for the Phaco-iStent group (P = .01). Thinner preoperative optical coherence tomography (retinal nerve fibre layer) thickness (hazard ratio [HR] = 7.34 [95% CI, 1.53-35.30]) and phacoemulsification alone (HR = 0.93 [95% CI, 0.87-0.02]) were independent factors associated with failure to achieve complete success.

Conclusions and relevance: Combined phacoemulsification with iStent implantation is associated with a higher likelihood of complete success compared with phacoemulsification alone in eyes with primary angle closure disease at 12 months postoperatively. Further studies are required to establish the longer term efficacy of iStent implantation and to identify other predictors for surgical success.

Keywords: angle closure; glaucoma; glaucoma incisional surgery; phacoemulsification.