TAG Episode 23 - 3Nov2014: ab-interno trabecular bypass surgery (AAC Enhanced)

[This AAC .m4a version has chapter markers and artwork embedded in the podcast to enhance the experience on devices/apps that support this, which includes most podcasting apps on iOS and Android devices. It is the preferred version for experiencing this podcast.]

In this episode, Tom Samuelson and I discuss trabecular bypass procedures including the currently available & two future models of the iStent, and the Ivantis Hydrus Microstent.  With iStent being the only currently FDA approved ab-interno trabecular bypass device, it is anticipated that the first generation iStent will serve as the control for future devices much like timolol is the standard to which all new glaucoma drugs are compared. There is a tendency for doctors to prescribe third and fourth glaucoma medications even though it is well known that there is such a diminishing return after two medications. These ab-interno devices can serve as a glaucoma-lite procedure, the next step after two medications for those reluctant to proceed with a potentially more effective but more risky trabeculectomy. With the iStent as it is currently approved in the United States (a single iStent and only combined with cataract surgery), it is hit or miss whether you actually reach a collector channel on the other side. The Hydrus, being 8 mm long instead of just 1 mm, is much more ikely to lead to outflow through a collector channel. The use of multiple iStents, next generation devices, or targeting delivery to visualized collector ducts should lead to improvements in ab-interno trabecular bypass procedures in the years ahead.

Even though this episode was originally recorded almost 1.5 years ago and I've only edited and posted today, no other devices aside from the 1st generation iStent have made it to market at this time so the material is all still relevant. Thanks to my listeners for sticking with me despite the paucity of episodes. I still have at least five more to edit and post and am always looking for new material if any glaucoma specialists want to talk. Please contact me at podcast@iguy.org. (Rob Schertzer, MD, MEd, FRCSC)

Thomas W. Samuelson is an adjunct associate pofessor of ophthalmology at the University of Minnesota and past chairman of the medical staff at the Phillips Eye Institute in Minneapolis. He is a faculty member at Hennepin County Medical Center, a major teaching hospital for the University of Minnesota residency program. On a national level, Dr. Samuelson is the recipient of the American Academy of Ophthalmology's Senior Achievement Award honoring contributions made to the Academy's educational programs.

Dr. Samuelson is the current Treasurer for the American Glaucoma Society and serves on its Executive Committee. He also oversees the glaucoma skills transfer courses for the American Academy of Ophthalmology (AAO). He serves on the Basic Clinical Science Course Committee for the AAO. Dr. Samuelson also serves as editorial board member and scientific reviewer for several ophthalmology journals.

Dr. Samuelson’s research interests include surgical procedures involving Schlemm’s Canal as well as the management of coincident cataract and glaucoma. He has also performed research on the safety of LASIK in patients with other ocular disorders, especially glaucoma. A frequent lecturer nationally and internationally (keynote lectures) on ocular surgery, he has published numerous scientific manuscripts and textbook chapters on ophthalmic surgery.

Dr Samuelson's contact information:
710 E. 24th Street Suite 100
Minneapolis, MN 55404

Phone: 612-813-3600
Fax: 612-813-3601


This episode was recorded live in March 2013 during the American Glaucoma Society annual meeting in San Francisco using a Shure SM58 microphone with a Marantz PMD661 digital recorder. Mixing and sound levelling were performed in November 2014 on a MacPro, using Levelator, Fission, and Garage Band. Narration was overdubbed using a Blue Microphone Yeti and Garage Band.

Opinions expressed in this podcast  are those of the speakers and are not intended to be taken as the standard of care for glaucoma treatment. Please always weigh the complete clinical picture and involve patients with any decisions in their care.
Selected references:

Thomas W. Samuelson, MD, L. Jay Katz, MD, Jeffrey M. Wells, PharmD, Yi-Jing Duh, PhD, Jane Ellen Giamporcaro, BS, US iStent Study Group: Randomized Evaluation of the Trabecular Micro-Bypass Stent with Phacoemulsification in Patients with Glaucoma and Cataract, Ophthalmology
Volume 118, Issue 3, March 2011, Pages 459–467.

Shakeel Shareef MD, Antonio Fea MD, PhD, Iqbal Ike K. Ahmed MD, FRCSC: The Hydrus Micro-stent. Surgical Innovations in Glaucoma 2014, pp 171-174.

Robert M Schertzer, MD, MEd, FRCSC
Assistant Professor of Surgery
Section of Ophthalmology
Giesel School of Medicine at Dartmouth
Dartmouth-Hitchcock Medical Center
1 Medical Center Dr
Lebanon, NH 03756

Work -    http://westcoastglaucoma.com
Twitter - http://twitter.com/robschertzer
Blog -     http://wholelottarob.com
email -   podcast@iguy.org

Theme music "Middle East Gold" ©Daniel Schertzer 2010 and published by Les Prods DOSWA Enr

 © Robert M Schertzer MD Inc, 2014