Two year efficacy of trabecular micro-bypass stent in patients with glaucoma and cataract
Sayegh Y, Baciu PD, Vanner EA, Maharaj AS, Wellik SR, Kishor K, and Junk AK. Two year efficacy of trabecular micro-bypass stent in patients with glaucoma and cataract. Invest Ophthalmol Vis Sci 2019; 60(9).
Invest Ophthalmol Vis Sci
Purpose: To evaluate intraocular pressure (IOP) and number of IOP lowering medications in open angle glaucoma patients with up to 24 months follow up after phacoemulsification with (iStent) or without (control) a first-generation trabecular micro-bypass stent (Glaukos Corporation, Laguna Hills).
Methods: This is a retrospective cohort study of 213 patients (276 eyes) with open angle glaucoma after phacoemulsification with (142 eyes) or without iStent implantation. Mean age was 71.9 years in the iStent group and 72.9 years in the control group. 117 individuals (55%) were female, of these 58 (40.9%) were in the iStent group. Data of 247 eyes (128 iStent) were available at 6 months [6M], 222 (123 iStent) at 12 months [12M], and 147 (91 iStent) at 24 months [24M].
Results: Number of medications prior to surgery were 2.1 in the iStent group and 1.2 in the control group (mean difference=0.9, 95% confidence interval (CI) [0.5,1.2], p O.0001); at 6M 1.5 and 1.4, at 12M 1.5 and 1.5, and at 24M 1.5 and 1.6, respectively. Prior to surgery, IOP was 18.0 in the iStent group and 15.8 in the control group (mean difference=2.3, 95% CI [1.2, 3.4], p<0.0001); at 6M 15.2 and 14.3, at 12M 14.8 and 13.7, and at 24M 14.6 and 14.7 mm Hg, respectively. The mean decrease in number of medications was significantly greater in the iStent group than the control group between pre-op and all 3 follow-up times: 6M mean=0.8 (95% CI [0.5,1.0], p<0.0001); 12M mean=0.7 (95% CI [0.5, 0.9], p <0.0001); and 24M mean=0.8 (95% CI [0.5,1.1], p<0.0001). The mean decrease in IOP was also significantly greater in the iStent group than the control group between preop and all 3 follow-up times: 6M mean=1.4 (95% CI [0.2, 2.5], p=0.0195); 12M mean=1.7 (95% CI [0.4, 3.1], p=0.0139); and 24M mean=2.8 (95% CI [1.2, 4.5], p=0.0006).
Conclusions: Eyes in both groups experienced an IOP lowering effect that was sustained over 24 months, but this was significantly greater in the iStent group. Eyes that received iStent had a significantly greater reduction in the number of medications than the control group, at every time point after surgery. Additionally, at every time point after surgery, the mean number of medications in the iStent group was fewer than pre-op, while the mean number of medications in the control group was more than pre-op.