Abstract
Purpose :
Of the minimally-invasive glaucoma devices, the Glaukos iStent has been increasingly used in Glaucoma centres, however there is a lack of long-term safety and efficacy data from the UK major centres. The aim of the current study is to assess the efficacy of iStent in lowering IOP and in reducing glaucoma medications over a long-term follow-up.
Methods :
Sixty three consecutive eyes of patients undergoing combined iStent with cataract extraction (phaco-iStent) were retrospectively reviewed. Inclusion and exclusion criteria for this study were: diagnosis of mild to moderate primary open angle glaucoma or ocular hypertension, and no previous glaucoma surgery. The following outcome measurements were recorded at baseline, and at 1 day, and at 3, 6, 9, 12 and 24 months after surgery: Intraocular pressure (IOP), number of IOP lowering medications, best corrected visual acuity (BCVA) and mean deviation (MD) on 24-2 Humphrey Visual Field Analyzer. Post-operative complications were also recorded. All data are expressed as mean ± SD with P <0.05 considered as significant.
Results :
The mean preoperative IOP and number of drops were 21.3 ± 6.5 mmHg and 2.4 ± 1.1 respectively. Significant reduction in IOP compared with baseline was observed at each interval with maximal reduction at 3 months (IOP 14.5 ± 3.2 mmHg P<0.05). This IOP reduction was sustained at 12 and 24 months (14.9 ± 2.7, and 15.1 ± 3.7 mmHg (P <0.05)). This was associated with a significant reduction in number of drops to 1.0 ± 1.2 at 1 year, and 0.5 ± 0.6 at 2 years (P <0.05). Non-significant changes of MD over the course of the study (-8.33 dB at baseline, -8.36 dB at 12, -9.80 dB at 24 months) were observed. No further glaucoma surgery was required at 24 months post-operatively. The following complications were successfully managed: transient post-operative IOP spike (>21 mmHg) (n=7), peripheral anterior synechiae (n=1), cystoid macular oedema (n=1), and IOL repositioning (n=1).
Conclusions :
Cataract surgery alone is known to lower IOP in addition to improving visual function. In our study we found an enhanced IOP reduction when performing phaco-iStent which correlated with less drops and less follow-up appointments compared to cataract extraction alone. This study in conclusion suggests that phaco-iStent can be regarded as a safe and effective procedure in lowering IOP and in reducing glaucoma medications over long-term follow-up in patients with mild to moderate glaucoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.