Fluorophotometric Study of the Effect of the Glaukos Trabecular Microbypass Stent on Aqueous Humor Dynamics

Abstract

PURPOSE. To evaluate the changes in aqueous humor dynamics and the efficacy and safety of the iStent (Glaukos Corp., Laguna Hills, CA), in combination with cataract surgery. METHODS. This investigation was a prospective, randomized, clinical study in patients with open-angle glaucoma or ocular hypertension who were undergoing cataract surgery. Aqueous flow (F) and trabecular outflow facility (C(T)) were measured by fluorophotometry before surgery and at months 1, 6, and 12 in both groups. RESULTS. Thirty-three eyes of 33 patients were randomized to either two stents and cataract surgery (n = 17, group 1) or cataract surgery alone (n = 16, group 2). Before surgery, F and C(T) were similar in groups 1 and 2 (1.78 +/- 0.44 and 1.74 +/- 0.82 microL/min, P = 0.18; 0.12 +/- 0.03 and 0.13 +/- 0.06 microL/min/mm Hg, P = 0.71, respectively). After surgery, there were no changes of note in F, however, C(T) increased in both groups. At 1 year, C(T) was 0.45 +/- 0.27 microL/min/mm Hg in group 1 and 0.19 +/- 0.05 microL/min/mm Hg in group 2 (P = 0.02), which represented increases of 275% and 46%, respectively. Mean IOP reduction was also greater in group 1 than in group 2 (6.6 +/- 3.0 mm Hg vs. 3.9 +/- 2.7 mm Hg; P = 0.002). The mean number of medications was significantly lower in group 1 than in group 2 (0.0 vs. 0.7 +/- 1.0, respectively; P = 0.007). CONCLUSIONS. Compared with cataract surgery alone, implantation of the iStent concomitant with cataract extraction significantly increased trabecular outflow facility, reduced IOP, and reduced the number of medications at 1 year. Longer follow-up is needed to assess the long-term effect on outflow facility. (ClinicalTrials.gov number, NCT00326066.).

Histological findings of failed gold micro shunts in primary open-angle glaucoma

“…As recently reported [24,25], implantation of the iStent concomitant with cataract extraction significantly increased trabecular outflow facility, reduced IOP and the number of medications at 1 year.…”

A Novel 8-mm Schlemm's Canal Scaffold Reduces Outflow Resistance in a Human Anterior Segment Perfusion Model

“…However, because many of the angle surgical procedures are combined with cataract surgery, postprocedure changes in aqueous humor dynamics are difficult to interpret. 21,22 Moreover, any incisional surgical procedure has the potential of altering the aqueous humor dynamics because of the local release of inflammatory mediators and postoperative use of steroids, which further confounds the assessment of aqueous humor dynamics, at least in the early postoperative period. In a more controlled environment, laboratory experiments of donated anterior segments can provide useful information on changes in outflow facility by angle surgical procedures or devices.…”

Modern methods of minimally invasive glaucoma surgery

“…Однако в настоящее время, согласно новым предвари-тельным данным, имплантация нескольких устройств мо-жет дать более выраженный гипотензивный эффект. Это подтверждается результатами экспериментов на перфузи-онной модели глаза и опытов in vivo с использованием ме-тода флюорофотометрии [24][25][26]. G. Belovay продемон-стрировал, что в случае установки двух или трех iStent имеют место более выраженное снижение уровня ВГД и сокращение потребности в гипотензивной терапии по сравнению с таковыми при имплантации одного мини-шунта [27].…”