Regulation of Intraocular Pressure via a Novel Adjustable Glaucoma Drainage Device

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Project Summary The proposed project aims at studying regulation of aqueous outflow for controlling intraocular pressure (IOP) of eyes by developing a novel adjustable glaucoma drainage device (AGDD). The proposed function of controlling IOP is empowered by a magnetic shape memory polymer (SMP) composite (M-SMP-C) valve that is integrated within a conventional shunt silicone tube. The shape of the M-SMP-C valve can be reprogrammed on demand by external magnetic fields, thus modulating the flow resistance of aqueous humor from the anterior chamber of the eye into the subconjunctival space outside of the wall of the eye. The modulation is continuous, postoperative, and non-invasive. To achieve the goal, recent development of novel responsive materials in the PI’s group will be leveraged to develop M-SMP-C consisting of a poly(glycerol-dodecanoate) acrylate (PGDA) and polyacrylic acid (PAA) (PGDA-PAA) shape memory elastomer which has a programmed shape change at 41 ℃ and two magnetic microparticles: neodymium–iron–boron (NdFeB) and Fe3O4. The preliminary results show that the proposed material has great biocompatibility, chemical stability, and mechanical properties. This project will be carried out to validate two hypotheses: 1) the fabricated M-SMP-C valve will show desired shapes under the magnetic fields through material and structure design; 2) shape reprogramming and deployment of the valve integrated in the AGDD will result in regulation of aqueous flow for IOP control. First, we will design and synthesize M-SMP-C followed by material characterizations of their microstructures to correlate the structures with the magnetic-mechanic response properties. Then the fabricated M-SMP-C valves will be integrated with a shunt tube to make an AGDD for in vitro study. The flow characteristics across the fabricated AGDDs will be studied and compared with the results from a computational fluid dynamic study. In turn, these results will serve as feedback to improve the material design and device fabrication. Finally, we will evaluate the material biocompatibility and device performance via ex vivo and in vivo studies. If successful, this proposed technology will show unprecedented advancement to address the long-standing issues inherited in conventional GDDs for IOP management. First, a surgical option will be developed to treat glaucoma by the proposed AGDDs which can be postoperatively and non-invasively adjusted on demand. This technology will address the clinical need despite the evolution of traditional GDDs in the past 50 years and the recent advent of minimally invasive glaucoma surgery (MIGS) shunting technologies. Second, capability of continuous and reversible valve adjustment will eliminate an otherwise tenuous and challenging postoperative course, thus obviating the need for reoperations and post-hoc modifications of available GDDs. Third, the proposed AGDD is compact and shows a similar structural form to a conventional GDD, thus will be familiar to the surgeons. In summary, this technology would represent a paradigm shift in the surgical management of glaucoma, helping to preserve the vision of millions of patients affected by this disease.