Novel Aqueous Humor Microshunt Implanted Alone or Combined With Phacoemulsification: 3-Year Follow-up
A feasibility study to evaluate the safety and efficacy of a micro-lumen aqueous drainage device made of poly(styrene-block-isobutylene-block-styrene) (SIBS), the InnFocus MicroShunt, used intraoperatively with mitomycin C (MMC), alone or in combination with phacoemulsification and intraocular lens (IOL) implantation.
Prospective nonrandomized study of 23 eyes in 23 primary trabeculectomy-stage patients who failed maximum tolerated glaucoma medication. Patients received a MicroShunt with intraoperative MMC (0.4 mg/mL, 3 minutes) either as an alone procedure or in combination with cataract surgery. A MicroShunt is implanted ab externo through a 3 mm-long needle tract in the sclera, draining aqueous humor from the anterior chamber to under the conjunctiva and Tenon's capsule. Main outcome measures include success rate (IOP ≤ 21 mmHg and ≥ 20% reduction in IOP from baseline), IOP, visual fields, visual acuity, medication use, and adverse events with 3 years follow-up.
The MicroShunt was implanted in 14 eyes alone and 9 eyes combined with cataract surgery. At 3 years (n=22), the qualified success rate (with or without glaucoma medication) was 95%; the complete success rate (with glaucoma medication) was 73%; the mean IOP was reduced from 23.8 ± 5.3 to 10.7 ± 3.5 mmHg (55%); mean glaucoma medications was reduced from 2.4 ± 0.9 to 0.5 ± 0.9, respectively. The most common complications were immediate postoperative transient hypotony (13%, 3/23) and transient choroidal effusion (8.7%, 2/23), all spontaneously resolved without sequelae. There were no sight-threatening long-term adverse events.
The InnFocus MicroShunt trans-scleral aqueous drainage tube implanted with MMC is a safe standalone as well as combined procedure with cataract surgery. Mean IOP reductions of >50% to approximately 10mmHg are achieved and sustained for 3 years. Results are comparable to trabeculectomy with MMC without the need for scleral dissection.