Abstract
Purpose :
to evaluate the demographic and biometric risk factors for success in intraocular pressure (IOP) lowering after cataract extraction with iStent® placement (CE-IS) compared to cataract extraction (CE) alone
Methods :
This is a retrospective effectiveness study of consecutive mild to moderate glaucoma patients who underwent CE-IS compared to CE alone. Averaged IOP and median medication use data available up to 1 year prior to the procedure was used as baseline. Inability to lower the number of medications or reduce the IOP by at least 20% compared to baseline on 2 consecutive visits was considered surgical failure. Using Cox proportional hazards models, univariate and multivariate survival analysis was performed with demographic (age, sex, race) and clinical variables (baseline IOP and medications, prior laser trabeculoplasty, biometric data) as predictors.
Results :
Forty-eight CE eyes (31 patients) and 61 CE-IS eyes (37 patients) were included in the analysis. In the CE-IS group, mean age was 71.0 years (range 52-90 years), 29.7% patients were male (n=11), and 86.5% of patients were Caucasian (n=32). In the CE alone group, mean age was 74.2 years (range 57-91 years), 45.2% were male (n=14), and 74.2% patients were Caucasian (n=23). Overall CE-IS had lower odds of failure than CE alone (HR=2.013; p=0.03). In Caucasian subjects, CE-IS had greater success as compared to CE alone (HR=2.86; p=0.008; see Figure 1). For non-Caucasian subjects there was no difference in the outcomes for the 2 procedures (HR=0.59; p=0.41; see Figure 2). Non-Caucasian race was associated with greater hazard of failure in CE-IS cases (HR 3.65, p=0.01) but not in CE cases (HR=0.91; p=0.86). In a multivariate model for CE-IS, biometric parameters were not associated with failure. For CE alone, greater odds of success were associated with lower corneal curvature (HR=1.60; p=0.003), higher anterior chamber depth (HR=0.22; p=0.004), and shorter axial length (HR=1.49, p=0.04).
Conclusions :
Addition of iStent® to cataract extraction was found to be beneficial in Caucasians but not in non-Caucasians. Noted variability in the success of CE-IS in published reports may be due to the varying racial compositions of the study populations. Associations between IOP lowering with CE and biometric parameters may allow for leveraging these clinical parameters for better case selection for MIGS procedures in glaucoma patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.