Current Developments in Glaucoma Surgery and MIGS

Successful interventional glaucoma remains a sought-after goal for the glaucoma clinician for many reasons. Medical costs, compliance, and adherence remain major barriers for the treatment of our patients. A truly definitive treatment for glaucoma is most likely to be largely surgical, as it is doubtful that patients will continue to use glaucoma drugs in the future for anything other than transient lowering of intraocular pressure. In the coming era, it seems probable that neuroprotection and neurorestoration will be combined with MIGS to lower pressure. Cost and access to medications, as well as cost-effectiveness are all reasons pushing towards surgery becoming the prime method of treating adult glaucoma, as is already the case for pediatric glaucoma. However, this could change if medications were to have a demonstrable beneficial effect upon the cells of the eye, whether corneal or trabecular. Cytoprotection, trabecular protection, and even canaloprotection may lie ahead to join the concept of neuroprotection. In fact, if medications were actually regenerative, it is likely that that they would become a routine component when MIGS is performed. At present, no such beneficial cellular treatment is known, but new medications based on neuroprotection and trabecular meshwork restoration may be on the immediate horizon. It has been suggested that netarsudil would have beneficial effects for both the trabecular meshwork and the optic nerve. Nitric oxide compounds may offer a similar possibility; much remains to be learned as of this writing. Additional good news is that the different types of MIGS are increasing in proportion to their efficacy. To date, there are no fewer than 12 choices available to glaucoma specialists. Choice of procedure depends on the underlying anatomy as well as the patient’s individual characteristics. Truthfully, the number of available surgeries depends upon their taxonomy. Most are based on the outflow system and the canal, as illustrated in Chapter 1 of this book.

Since our last book on the topic, Surgical Innovations in Glaucoma, the surgical landscape has shifted considerably; in only a few years, much has become obsolete, replaced by more recent findings and techniques. Due to significant improvements, MIGS are increasingly finding their place in patient management to such a degree that a monograph is no longer a suitable format to keep track of all the developments in this area. This collection of articles is intended to be the first of a series of planned books on glaucoma surgery. It follows the format and citability of another glaucoma series from Kugler Publications, Glaucoma Research and Clinical Advances, soon to publish its third volume.

Comments and contributions to this new surgical series are very much welcome. We hope that this volume will not only enhance the reader’s clinical care, but will also spark a dialogue that aids us all in increasing the quality of care we render to our patients.

John R. Samples, MD Clinical Professor, Washington State University Floyd Elson College of Medicine, Spokane, WA, USA Director, Western Glaucoma Foundation, Sisters, OR, USA Founder and Organizer, Trabecular Meshwork Study Club

Iqbal Ike K. Ahmed, MD, FRSC (C) Assistant Professor, University of Toronto, Toronto, ON, Canada Clinical Professor, Salt Lake City, University of Utah, UT, USA Director, Glaucoma & Advanced Anterior Segment Surgery (GAASS) Fellowship, University of Toronto, Toronto, ON, Canada Research Director, Kensington Eye Institute, University of Toronto, Toronto, ON, Canada Division Head, Ophthalmology, Trillium Health Partners, Mississauga, ON, Canada Medical Director, Prism Eye Institute, ON, Canada Co-Medical Director, TLC Oakvillle, Oakville, ON, Canada

Foreword

About the editors

About the authors

1. Anatomy of the conventional aqueous outflow pathway
Haiyan Gong, David L. Swain

2. Patents in an age of innovation
William Noonan

3. Which minimally invasive glaucoma surgery should one choose for a specific patient?
Jithin Yohannan, E. Randy Craven

4. In defense of the trabeculectomy
Ryan Machiele, Makena Parker, Leon W. Herndon

5. On the use of curcumin as a multimodal antifibrotic agent for glaucoma surgery
Nicholas M. Pfahler, Michael C. Giovingo, Paul A. Knepper

6. The future of MIGS
Thiago A. Moulin, Arsham Sheybani

7. Gonioscopy-assisted transluminal trabeculotomy (GATT)
Ronald L. Fellman, Davinder S. Grover

8. HydrusR microstent
Thiago A. Moulin, Arsham Sheybani

9. The iStent devices: iStent, iStent inject, and iStent Supra
Antonio M. Fea, Simona Scalabrin, Carlo Lavia

10. Ab interno trabecular meshwork incision, ablation, and disruption
Hamed Esfandiari, Si Chen, Ralitsa T. Loewen, Susanna Waxman, Kevin Kaplowitz, Nils A. Loewen

11. iTrack™ ab interno canal-based glaucoma surgery: the next evolution in MIGS
Mahmoud Khaimi, David Lubeck

12. XEN: the evolution of the stent and technique
Vanessa Vera, Daniel Lee, Natasha N. Kolomeyer, M. Reza Razeghinejad, Jonathan S. Myers

13. An ab externo minimally invasive aqueous shunt comprised of a novel biomaterial
Leonard Pinchuk, Isabelle Riss, Juan F. Batlle, Henny Beckers, Ingeborg Stalmans

14. Laser trabeculoplasty and micropulse: evolution from trabecular photocoagulation, to trabecular photothermolysis, to trabecular photostimulation
Giorgio Dorin, Ted S. Acott, Antonio M. Fea, John R. Samples

15. Cyclophotocoagulation
Michael Giovingo, Shyam Patel, Shweta Chaudhary, Amar Mannina, Thomas Patrianakos

16. Excimer laser trabeculostomy: the laser-based MIGS procedure for open-angle glaucoma
Michael S. Berlin, Marc Töteberg-Harms, Jonathan Shakibkhou, Alyssa Francesca Ahorro, Ryan Lamrani, Antonio Moreno Valladares, Ulrich Giers

17. Mixing and combining MIGS procedures
Steven R. Sarkisian, Jr.

18. Trabeculectomy with suprachoroidal derivation
Rodolfo A. Pérez-Grossmann, Daniel Grigera, Alan Wenger, Rodolfo A. Pérez-Simons

19. Modern retinal laser for neuroprotection in open-angle glaucoma
Jeffrey K. Luttrull, David Kent

20. What is the ideal conjunctival bleb and how to achieve it? Learning from the Microfistula-XEN procedure
Dao-Yi Yu, Stephen John Cringle, William H. Morgan, Er-Ning Su

21. Special considerations for pediatric glaucoma
Peter A. Netland, John R. Samples