Pilocarpine Use After Kahook Goniotomy

Glaucoma is the leading cause of irreversible blindness worldwide, and its treatment consists of lowering intraocular pressure to prevent damage to the optic nerve and loss of vision[1]. Current methods for lowering intraocular pressure (IOP) include topical and oral medications, laser trabeculoplasty, microincisional glaucoma surgery (MIGS), and traditional incisional surgeries such as trabeculectomy and aqueous tube shunts. MIGS have become more popular in recent years as less invasive methods than traditional surgeries that effectively reduce IOP and help reduce the medication burden on patients[1]. There are multiple available MIGS procedures, most of which act by increasing trabecular outflow. One such procedure is the goniotomy via Kahook Dual Blade (KDB), which is usually performed in combination with cataract surgery. KDB is an FDA approved device used to perform a goniotomy via an internal approach. Strips of the nasal angle trabecular meshwork are removed providing a direct pathway for aqueous outflow from the anterior chamber into the collector channels[2].

Pilocarpine, a parasympathomimetic agent, is a glaucoma medication that works by causing contraction of the ciliary muscle leading to opening of the trabecular meshwork[3]. Due to its frequent dosing requirement and large number of ocular and systemic side effects, pilocarpine has largely fallen out of favor for the treatment of primary open angle glaucoma (POAG), except in patients for whom few other alternatives exist. However, pilocarpine is often used after goniotomy surgery. The rational for its use after goniotomy procedure is for its miotic effect, which theoretically may prevent the formation of peripheral anterior synechiae. Formation of peripheral anterior synechiae can lead to the closure of the cleft that is generated and the possibility of failure of the procedure. While the theoretical benefit of pilocarpine has been proposed, its actual benefit has never been proven. This study will evaluate whether goniotomy via KDB / Cataract surgery without pilocarpine is non-inferior to the same surgery procedure followed by treatment with pilocarpine.