Outcomes following iStent inject implantation: a single centre experience in the UK
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First Author: S.Haldar UK
Co Author(s): A. Rajammal M. Kinsella A. Shaikh
iStent inject is a second generation trabecular micro-bypass MIGS device which permits increased trabecular outflow by allowing fluid to pass from anterior chamber into schlemm’s canal. We aim to assess the efficacy, safety and cost effectiveness of the iStent inject implant in the treatment of glaucoma patients.
Follow up data up to a year from iStent inject Implantation, both standalone and combined with cataract surgery by two glaucoma surgeons in a regional UK centre. The outcome data from iStent inject implantation between November 2018 and February 2020 were identified and suitable cases were retrospectively analysed.
84 procedures were identified through theatre registers and electronic records. Patients with less than a minimum 4 week follow up or those who were on topical steroid treatment at last IOP measurement were excluded. 72 procedures were suitable for inclusion. 60 procedures were iStent inject implantation combined with cataract surgery, 12 procedures were iStent inject implantation alone. In all patients preoperative and postoperative visual acuity, IOP and number of glaucoma drops as daily regimen data were collected.
72 eyes were implanted with iStent inject. Mean patient age was 76 years (SD 8.4). 74% (n=53) were POAG. Mean visual field MD preoperatively was -6.5 dB. 63% (n=45) of patients had over 6 months postoperative data. Postoperatively mean intraocular pressure reduced by 4mmHg and patients needed a mean of 0.9 fewer glaucoma medications. Preoperatively 3% of patients (n=2) were drop-free. Postoperatively 21% (n=15) were drop free. 69% (n=50) had improved LogMAR scores, 24% (n=17) were stable and 7% (n=5) deteriorated. There were no intraoperative complications. One patient required peripheral laser iridoplasty and 4% (n=3) needed further pressure lowering intervention.
Our data shows that iStent Inject is associated with a mean IOP reduction of 4mmHg and a 39% reduction in glaucoma medications taken. Importantly this resulted in 21% of patients being able to stop all drops and 28% on only one agent. No iStent inject related visual acuity issues have been observed to date. We report no intraoperative or significant postoperative complications and can conclude that iStent inject is a safe and effective trabecular microbypass procedure. For our reaudit we plan to expand the patient cohort, length of follow up data and aim to quantify the cost effectiveness.