Abstract
Purpose:
This study evaluates the efficacy and safety of the Glaukos iStent implant in conjunction with cataract extraction compared to cataract extraction alone in patients with open-angle glaucoma and cataracts.
Methods:
Retrospective chart review of medical records of patients with mild to moderate open-angle glaucoma and visually significant cataracts who underwent cataract extraction with concurrent implantation of the Glaukos iStent device. These results were compared to a control group of patients with mild to moderate open-angle glaucoma who underwent cataract extraction alone.
Results:
30 eyes of 24 patients were reviewed in the iStent group and 16 eyes of 16 patients in the control group. The mean age at time of surgery was 75.8 years in the iStent group compared to 77.6 years in the control group. Pre-operative characteristics showed average central corneal thickness (CCT) of 549 uM, average retinal nerve fiber layer (RNFL) thickness of 67.5 uM, and average mean deviation on 24-2 Humphrey Visual Field Testing (HVFT) of -6.23 dB in the iStent group. The control group had average CCT of 542 uM, average RNFL thickness of 75.8 uM, and average 24-2 HVFT mean deviation of -5.0 dB. Pre-operatively, the mean IOP was 16.0 mmHg and the mean number of topical pressure lowering medications being used was 1.7 in the iStent group, with pre-operative IOP in the control group of 15.6 mmHg and mean number of topical medications 1.5. At 1-year follow-up, change in IOP from baseline was +1.3 in the iStent group and +0.3 in the control group. Mean change in number of medications from baseline was -0.6 and -0.2 in the iStent and control groups respectively. Interestingly, IOP was better controlled in the iStent group at the 1 day post-operative visit with average IOP increase of 2.7 mmHg compared to an increase of 8.1 mmHg in the control group. Few patients experienced any post-operative complications in the iStent group with the most common being a post-operative hyphema.
Conclusions:
Our early experience with the iStent indicates it to be a safe surgical intervention for the appropriate patient. While mean IOP did not change significantly, patients used fewer topical medications to control their intraocular pressure, and we found a potential protective effect at preventing pressure spikes in the early post-operative period.