Part 7 of 14 of “Adjusting the Faucet or Opening the Drain – Currently Available Methods to Treat the Plumbing Problem of Open Angle Glaucoma” | A San Gabriel Valley Optometric Society (SGVOS) Continuing Education Dinner Event – 2 hours CE | Featured Speaker: Dr. David Richardson, MD | April 12, 2017
Currently Available Incisional Treatments for Glaucoma (Traditional “Penetrating” Surgical Methods)
These are what we can basically split into Penetrating (the more traditional ones) and the Lower Risk Surgeries, which are called “minimally invasive glaucoma surgeries” or “Micro Invasive Glaucoma Surgeries”—basically MIGS.
And we’ll go over how well MIGS go, in a second, because you may have heard the tongue- in-cheek term, MEGS— M-E-G-S for Minimally Effective Glaucoma Surgery and we’ll see whether or not that’s case.
We all know about trabeculectomy— you create a fistula, so a shunt creates a bleb, the issues of bleb failure, lifetime risk of infection and lifestyle limitation. You can’t wear contact lenses; in general, you can’t go snorkelling or scuba diving— things like that. For our active baby boomer patients, this can be an issue. There’s also other issues—you can have cystic blebs, resulting in ocular surface disease, you have scarred bleb, which is quite (you know) in five years after trabeculectomy, its more likely to have a cataract from the trabeculectomy than you are to have a working bleb. You know, they’ve been around since 1968 and they’ve really not changed much in that time so I think that we can all agree it’s time to move on. And we’re going to be talking about the potential methods by which we can move on.
Glaucoma Drainage Devices
Traditional penetrating surgeries also include the Glaucoma Drainage Devices.
Essentially there are two that are commonly used here in the in the US — the non-valve, which is the Baerveldt® versus the valve, which is the Ahmed™ and these have a number of issues along with — that are shared as well as somewhat unique from Trabeculectomy. And in the case of the Trabeculectomy and Glaucoma Drainage Devices the main risks are pressure elevation and hypotony—so both extremes there. In the case of the Glaucoma Drainage Devices, you’ve put an implant on the surface of the eye, underneath the conjunctiva, so not surprisingly the implant can sometimes move, you can give them the trouble with that, you can get an infection — if you get an infection on an implant, whether it’s an implant in the eye or anywhere else, that’s a big issue. You generally have to remove the implant. It’s very hard to eliminate an infection on any non-biologic tissue. Scarring can cause double vision. And then there are other things — the implant itself — the tube can erode. With Glaucoma Drainage Devices as well as Trabeculectomy, if you end up with a sudden drop in pressure, you can end up with a suprachoroidal hemorrhage— a bleed in the back of the eye that can lead to a total loss of vision or at least put you at great risk of that.
So essentially after incisional glaucoma surgery that’s the only time I will ever tell my patients that not only can they use a laxative or stool softener but I want them to. Because I want them to avoid any Valsalva maneuver, anything that could cause an increase in venous pressure resulting in back flow into a hypotenuse eye. So given those risks and given the fact that with glaucoma, we’ve got patients that generally can see and we’re trying to keep them from losing vision. I don’t like offering surgical treatments that have a high risk of loss of vision.
Currently Available Methods to Treat Open Angle Glaucoma Series:
- Currently Available Methods to Treat Open Angle Glaucoma
- Beta-blockers, Selective Alpha Adrenergic Agonist, CAIs
- Prostaglandin Analogs, Cholinergic Receptors Agonists, Fixed Combination Agents
- Carbonic Anhydrase Inhibitors (CAIs)
- Laser Trabeculoplasty
- Continuous Wave and Micropulse® Cyclophotocoagulation
- Trabeculectomy and Glaucoma Drainage Devices
- Ab-Externo Canaloplasty
- Ab-Interno Canaloplasty
- IStent®, Cypass® Microstent, Xen® 45 Gel Stent, Cataract Surgery
- Next-Generation Glaucoma Medications and Surgeries
- iStent Supra®, Hydrus™ Microstent, and InnFocus MicroShunt®
- Canaloplasty with Stegmann Canal Expander