The Kahook Dual Blade (New World Medical) is a simple yet elegant device designed to reduce IOP through the removal of a section of trabecular meshwork (TM) and the inner wall of Schlemm canal. Under direct gonioscopic visualization, the dual blade is inserted through a clear corneal incision and advanced to the opposite angle. The sharp tip of the device is used to pierce the TM and enter the canal. As the instrument advances in the canal, the ramp of the device gently elevates the TM toward the dual blades on either side of the device where it is incised. The result is a nearly complete excision of the TM from an ab interno approach.
The procedure of incising TM to increase aqueous outflow has long been established as a means of reducing IOP in glaucoma. Long-term success in adults with the disease has been limited, however, in part due to the residual TM leaflets that can scar closed postoperatively. The novelty of the Kahook Dual Blade resides in its ability to more completely remove TM, which one hopes will achieve better long-term outcomes. In cadaver eyes, my colleagues and I have shown that TM excision with the dual blade is more complete than with the Trabectome (NeoMedix) or a microvitreoretinal blade.1
My initial experience with the device has been positive. The procedure itself is relatively straightforward and quick to perform. It can be a stand-alone procedure or performed in combination with cataract surgery. I have achieved excellent IOP outcomes thus far, especially when I have combined the Kahook Dual Blade with endoscopic cyclophotocoagulation, which targets aqueous production in addition to outflow without leaving an implant behind. In patients with peripheral anterior synechiae, I have used the dual blade not only to perform goniosynechiolysis but also subsequent TM removal. The most common postoperative complication is hyphema, which is typically mild and to be expected after most forms of goniotomy or trabeculotomy.
Long-term data on efficacy and safety are needed to better determine where this device fits in the glaucoma surgeon’s armamentarium.
1. Seibold LK, Soohoo JR, Ammar DA, Kahook MY. Preclinical investigation of ab interno trabeculectomy using a novel dual-blade device. Am J Ophthalmol. 2013;155(3):524-529.
Leonard K. Seibold, MD
• assistant professor of ophthalmology, University of Colorado School of Medicine, Aurora
• financial disclosure: consultant to New World Medical