iStent May Reduce the Need for Glaucoma Drugs After Cataract Surgery
JAMA Ophthalmology, January 2019
Wang et al. compared postoperative use of ocular antihypertensive drugs among patients who had cataract surgery alone and those who underwent cataract surgery and received the iStent Trabecular Micro-Bypass (Glaukos). They found that, by 20 to 24 months following surgery, the standalone group needed substantially more glaucoma medications.
For this retrospective longitudinal study, the authors included patients enrolled in a U.S. managed care network who had cataract surgery plus the iStent (n = 1,509 bilateral; n = 1,462 unilateral) as well as a control group that received bilateral cataract surgery only and was matched (1:1) to patients who had bilateral iStent/cataract surgery. All procedures were performed between 2012 and 2016. The main outcome measure was the number of topical ocular antihypertensive agents used postoperatively versus preoperatively (baseline).
Diagnoses of those who underwent iStent/cataract surgery were primary open-angle glaucoma (78.4%), narrow angles (12.8%), and secondary glaucoma (8.8%). At baseline, 41.2% of this group were not receiving a topical glaucoma agent, and 29.5%, 14.7%, and 14.6% were receiving 1, 2, or ≥3 agents, respectively. Among the 22.8% of iStent/cataract surgery participants who completed at least two years of postoperative follow-up, the authors observed an increase (to 64.7%) in the number who required no drops by 20 to 24 months postoperatively (p < .001, χ2 test). Patients using at least one topical agent at baseline had a mean reduction of 1.01 and 0.61 in the number of medications by 20 to 24 months after bilateral or unilateral surgery, respectively (both p < .001, paired t test). Sustained reduction in medication use was more common for patients who had at least three medications at baseline versus only one medication (hazard ratio, 1.68).
Compared with matched controls who underwent cataract surgery alone, those with the combination procedure had a greater reduction in the mean number of drops used by month 20 to 24 (0.99 vs. 0.49; p < .001, paired t test). Moreover, a larger percentage of the iStent/cataract surgery group were receiving no drops by the 20-to 24-month mark (73.5% vs. 55.3%; p < .001; χ2 test).
These findings support those of smaller studies showing that the iStent in combination with cataract surgery reduces dependence on ocular antihypertensive drugs following surgery.
The original article can be found here.