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Part 6 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 (FDA-approved) Laser Treatments (“Cyclodestructive” Procedures for Glaucoma)
Continuous Wave Cyclophotocoagulation
Ab-Externo Continuous Wave Cyclophotocoagulation
This is, traditionally been, reserved for those patients who have end-stage glaucoma where there’s no potential for vision. It’s just a blind, painful eye. And you’d place this laser spots transscleraly, you destroy the ciliary body and you’d lower the pressure. But you could also lower it too much—you could essentially destroy the aqueous production and end up with a hypotenuse or even Phthisical Eye. So this is not really used for too many patients. But it did have its use.
Ab-Interno Continuous Wave Cyclophotocoagulation – EndoCycloPhotocoagulation (ECP)
Then there’s the Ab-Interno – the newer version, the EndoCycloPhotocoagulation (ECP) and the most exciting (I think) is the newest iteration of this is Micropulse® Cyclophotocoagulation (MP3).
So the Ab-Externo which is from the outside of the eye, continuous-wave cyclophotocoagulation— we just talked about that. It was pretty uncomfortable. Nope, it was downright painful. You actually had to block the eye or put somebody under anesthesia. And then not only— this is the other thing—not only could you get hypotony but there was even the possibility that you could get sympathetic ophthalmia from the severe inflammatory response. So you treat one eye and the other eye would go blind. Not ideal. So this is why we didn’t see much of this but because it did have its use it stayed around for a while. And eventually people figured out how to use this technology in a safer way that was still effective.
And so EndoCycloPhotocoagulation was developed. This can be used for mild to moderate glaucoma it has to be done at the time of or after cataract surgery and it’s relatively low-risk glaucoma but it’s also you know relatively modest in its effect. And it does, as with anything you do with the iris or the ciliary body, it’s going to result in some inflammation.
So here is an animation of the ECP. A viscoelastic is placed in the in the eye a probe is then inserted and the individual ciliary body processes are then lasered and the trick is to shrink them. You have to shrink them enough that the epithelium stops producing aqueous. But you don’t want to actually pop them. And what happens is you see them shrink and if you go beyond the shrinking they pop like popcorn. And unfortunately that pop is so incredibly pro-inflammatory that this procedure is very much surgeon-dependent. So if the surgeon understands the nuances of the procedure you can get a nice effect without too much inflammation. If they’ve got a heavy hand or heavy foot, as the case may be it, it can actually result in a lot of inflammation.
Micropulse® Cyclophotocoagulation (MP3)
This is, I think, as I said the one of the most exciting laser treatments that’s available. This uses, as we talked about before, micropulses. You’ve got tiny little pulses followed by a pause allowing for the thermal relaxation. So this was thought of as a gentler form of Cyclophotocoagulation. Nobody really knew how it worked. I mean if you’re not destroying the ciliary body process how in the world are you getting any reduction in aqueous. Well turns out you’re not. It doesn’t work by reducing aqueous. It works by pulling on—on the posterior trabecular meshwork and essentially enhancing outflow just like pilocarpine.
Nice thing about this is although it is uncomfortable and you still have to either block or put some of the– quick five minutes of IV sedation, it’s generally comfortable afterwards, very low risk, and it works— works well as we’ll see in a moment.
So this is the slow application. The lasers chopped in the micropulses. The early studies looked at patients who just like with Transscleral, continuous wave Cyclophotocoagulation were kind of end-stage patients —you can see these are patients with pressures in the 40’s. And they come down in the mid 20’s. Since that time, they’ve also studied patients who have more reasonable pressures and the studies seem to indicate that they do (about) as well, in terms of the percent reduction. And this is the procedure it’s an external procedure… There’s no incision it does not have to be done under sterile conditions, and essentially you make about nine passes superiorly, nine passes inferiorly of this laser. And it’s not technically challenging although it can be somewhat challenging in patients who have small palpebral fissure because if you don’t get the laser posterior enough you can end up with a change in the pupil size and potential inflammation. And that’s probably the reason why pupil dilation is relatively common.
Dr. David Richardson offers Selective Laser Trabeculoplasty (SLT) as an outpatient procedure in his San Marino Eye office. SLT can be performed on the same day as most examinations and the whole procedure takes 5 minutes of less. SLT is a gentler glaucoma laser surgery. Contact Dr. David Richardson immediately to see if SLT is for you. Call today to schedule an appointment with Dr. Richardson at 626.289.7856.
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