The development of SIBS and the InnFocus MicroShunt®












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This chapter summarizes the almost two-decade development path leading to the availability of the InnFocus MicroShunt®, beginning in the first decade with the development of a unique and novel inert biomaterial called poly(styrene-block-isobutylene-block-styrene) or “SIBS” to serve as an ultra-biocompatible foundation for a vast array of implantable medical devices. The second decade involved developing a robust glaucoma shunt that required three iterations of design and four clinical trials. The development path drove the one-year qualified success rate for glaucoma surgery with the device from 43 to 100%. The InnFocus MicroShunt® is a minimally invasive, plateless, glaucoma drainage micro-shunt made from SIBS that is used to shunt aqueous humor from the anterior chamber to a potential space formed under the conjunctiva and Tenon’s capsule. The unique chemistry of SIBS does not provoke clinically significant fibrotic capsule formation, thereby minimizing the potential for tissue to block the lumen of the device and inhibit its function. The 70 μm diameter lumen and 8.5 mm length of the device was designed to produce an optimal pressure result for glaucoma surgery. The clinical performance of the MicroShunt approaches that of trabeculectomy with Mitomycin C, the gold standard for glaucoma surgery. The minimally invasive surgical placement and lack of trauma to the eye meets or exceeds the safety of trabeculectomy. The impetus to develop this device stemmed from the need for a safer method of treating glaucoma with more predictable outcomes, which can be used earlier in the treatment paradigm for glaucoma. A secondary goal was to design the device to be used by ophthalmic surgeons worldwide, to be implanted in a controlled manner, without the need for sophisticated equipment. This chapter explains the chemistry of SIBS, why it is well-tolerated in the eye, and then briefly reviews the development path leading to the InnFocus MicroShunt®.

Glaucoma Research 2018-2020, pp. 299-312 #21
Edited by: John R. Samples and Paul A. Knepper
© Kugler Publications, Amsterdam, The Netherlands

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