The current era has been described as a “Renaissance Period” in glaucoma surgical care. Our care has been revolutionized with innovative techniques and devices designed to enhance physiologic aqueous outflow pathways in patients with mild stages of glaucomatous optic neuropathy. Although these techniques in this specific patient population have deservedly taken the spotlight with regard to advancing glaucoma treatment paradigms, it is important to note similarly transformative treatment strategies for patients with late stages of the disease as well as those experiencing persistent complications in the postoperative period. This textbook aims to shed light on these strategies for a host of complex entities that may present to the glaucoma surgical consultant.

Drs. Hu and Moster describe use of a novel trabecular micro-bypass stent to access and enhance physiologic aqueous outflow pathways for the treatment of mild glaucomatous optic neuropathy (Chap. 2). In its current iteration, a single micro-bypass stent (iStent, Glaukos Corp.) is attached to a disposable inserter. The device is currently approved for insertion in conjunction with cataract surgery. Upgrades in stent design are currently under study and will allow for multiple stents to be placed with a single inserter. Current evidence supports multiple stent insertion for enhanced aqueous outflow [1]. In addition, targeted stenting may increase rates of success by increasing chances of accessing functioning trabecular collector systems.

Drs. Kaplowitz and Loewen describe the use of the trabectome procedure (Neomedix, Inc.) for the treatment of complex angle-closure glaucomas (Chap. 3). Although typically categorized as a microinvasive procedure with typical indications, the authors describe a technique with encouraging results for the reversal of peripheral anterior synechiae. In addition, the authors describe the use of the device after failed conventional glaucoma filtering procedures [2]. Supplemental video of the technique as performed by Dr. Nils Loewen provides invaluable instruction.

The conventional treatment paradigm for angle-closure glaucomas is currently under investigation, with lens extraction becoming a prime consideration in earlier stages of the disease. Drs. Trikha, Perera, Husain, and Aung provide convincing evidence from anterior segment imaging studies to support this approach (Chap. 4) [3]. Indeed, the high-quality pre- and postoperative figures in this chapter reveal a marked improvement in angle crowding with presumed enhancement in trabecular outflow. The authors provide guidance for the performance safe cataract removal under challenging preexisting conditions of a shallow anterior chamber with angle closure.

Drs. Grover and Fellman describe a truly innovative technique, Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) (Chap. 5). The technique involves use of the iTrack microcatheter for performance of ab-interno trabeculotomy for the treatment of adult and developmental glaucomas. Advantages of this technique include sparing of the conjunctiva and the ability to visualize safe cannulation of Schlemm’s canal. The group recently reported a 39.8 and 52.7 % decrease in IOP with this technique in primary and secondary open angle glaucomas, respectively, after 12 months of follow-up [4].