Predictors of Intraocular Pressure Lowering after Phacoemulsification and iStent Implantation

Shaza N. Al-Holou, Shane J. Havens, Gillian G. Treadwell, Deepta Ghate, Carol B. Toris, Vikas Gulati

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Purpose: To explore the demographic and clinical variables associated with intraocular pressure (IOP) lowering after cataract extraction (CE) alone or CE in combination with the iStent (Glaukos Corporation) placement (CE+IS). Design: Retrospective data extraction and survival analysis of consecutive patients identified over a 2-year period. Participants: Patients with mild to moderate glaucoma who underwent CE (48 eyes of 32 patients) or CE+IS (61 eyes of 37 patients) were analyzed. Methods: Inability to reduce the number of medications or the IOP by at least 20% compared with baseline on 2 consecutive visits was considered surgical failure. Using Cox proportional hazards models, survival analysis was performed, and demographic and clinical variables were evaluated as risk factors. Main Outcome Measures: Time to failure after surgical procedure. Results: CE+IS had lower odds of failure than CE alone (hazard ratio [HR], 2.01; P = 0.047). In White patients, CE+IS showed greater odds of success compared with CE alone (HR, 2.86; P = 0.007). For non-White patients, no difference was found in the outcomes for the 2 procedures (HR, 0.59; P = 0.48). In the multivariate analysis, non-White race (HR, 8.75; P = 0.0002) and longer axial length (HR, 1.61; P = 0.03) were associated with greater hazard of failure after CE+IS. In the CE group, greater odds of failure were associated with steeper corneal curvature (HR, 1.74; P = 0.008), shallower anterior chamber (HR, 0.22; P = 0.008), and longer axial length (HR, 1.58; P = 0.01). Conclusions: Addition of the iStent to CE improved the duration of IOP lowering in White patients, but not in non-White patients. Associations between IOP lowering after CE and biometric parameters may allow for leveraging these clinical parameters for better case selection for these procedures.

Original languageEnglish (US)
Pages (from-to)139-148
Number of pages10
JournalOphthalmology Glaucoma
Issue number2
StatePublished - Mar 1 2021


  • Glaucoma surgery
  • Intraocular pressure
  • Minimally invasive glaucoma surgery
  • iStent

ASJC Scopus subject areas

  • Ophthalmology


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