Purpose
Microinvasive glaucoma surgery (MIGS) is a burgeoning field with no available data to date regarding outcomes when performed by residents in training. In a retrospective, observational fashion, we evaluated early efficacy and safety outcomes of resident-performed MIGS using the iStent in a veteran population.
Methods
Data were collected through a retrospective chart review at a Veterans Affairs Medical Center (VAMC) since the iStent became locally available in 2014. Patients were included who underwent combined cataract extraction and placement of an iStent by an ophthalmology resident in his/her 3rd year of training under the supervision of a single, fellowship-trained glaucoma surgeon. Baseline parameters were obtained, including demographics, intraocular pressure (IOP), number of ocular antihypertensive medications (meds), cup-to-disc (C:D) ratio, and best corrected logMAR visual acuity (BCVA). Mean age at surgery was 72.4 ± 8.6 years. Measurements were evaluated postoperatively at 1 day, 1 week, and 1 month. In addition, intraoperative and post-operative complications were recorded.
Results
Of 25 iStents placed by residents in 2014 at the VAMC, 24 eyes in 19 patients were included. One was excluded due to failure to place the device. Preoperatively, mean IOP was 18.0 ± 4.9 mmHg (range: 11-32). IOP averaged 19.6 ± 6.8 (n = 24) and 19.0 ± 4.9 (n = 17) mmHg at 1 day and 1 week, respectively. By 1 month, mean IOP was 16.8 ± 3.6 mmHg (range: 11-25) (n = 22), representing a 6.7% reduction in IOP from baseline (P = 0.32). Baseline C:D ratio was 0.65 ± 0.16. BCVA improved from 0.45 ± 0.39 to 0.07 ± 0.11 by 1 month (P = 0.02). Number of meds was not statistically different at 1 month (P = 0.81). There were no intraoperative complications associated with the iStent. Within the first week, 5 eyes developed a microhyphema within the first week, which all resolved without intervention.
Conclusions
When performed by senior ophthalmology residents, MIGS, when combined with cataract surgery, impose minimal risk to patients and produce modest early reductions in IOP in a veteran population. These data may aid with counseling patients preoperatively for resident-performed iStent implantation.