By Michael J. Siegel MD, FACS
In the realm of minimally invasive glaucoma surgeries (MIGS), endoscopic cyclophotocoagulation (ECP) has faced barriers of residual historic bias from both transscleral cryotherapy and transscleral diode therapy (TSCPC). Both were “blind” procedures done on advanced stage eyes where the goal was to aggressively treat the ciliary processes from an external approach, shrinking (or freezing) them to lower aqueous production.
With the advent of ECP, we could visualize the ciliary processes to treat more effectively, delivering less energy with greater safety and efficiency. However, many approached ECP with the mindset that they would extrapolate their techniques with cryotherapy and TSCPC, treating advanced patients with the endpoint of complete destruction of the ciliary processes. Popping or “blowing up” of the ciliary processes had the expected challenges—namely significant inflammation, pain, loss of vision, and poor outcomes.
Over time the technique adapted; many surgeons quickly realized that visualization allowed them to provide a more titrated treatment. Instead of blowing up the ciliary processes in advanced cases, one takes the opposite approach and gently and mildly treats the visible ciliary processes, thereby reducing the inflammatory cascade, yet still getting significant aqueous suppression. My colleagues and I studied ECP outcomes using this approach and found that phaco+ECP lowered IOP ≥20% below baseline at 36 months,1 and IOP was still 19.2% lower at 72 months,2 enabling patients to use at least one fewer medication. Titration and gentle energy delivery are the keys to ECP’s success.
How-To: Safe, Effective ECP
A gentle ECP technique is not difficult to master. Here are some key concepts and techniques.
Visualizing the ciliary processes – Through the single clear corneal incision utilized for cataract surgery, utilize a 19-gauge curved tip, which allows for access to nearly 300 degrees of the ciliary processes. (A straight probe is also available but requires a second incision to reach a similar treatment area.)
Following IOL placement, inject OVD (usually a cohesive) to fill the ciliary sulcus space. The circulator controls the machine, getting you lined up and in focus prior to entry. When you enter the eye, the goal is to get 4-5 ciliary processes in your view with your probe, which offers a good approximation of the appropriate distance so that when you fire the laser you get reasonable energy delivery with less risk of the laser being “too hot.”
Using the laser – Each laser setup is a bit different in the power settings, but the starting point is somewhere between 150-250 mW. When applying laser energy to the tips of the ciliary processes, the goal is mild shrinkage, lightening and whitening. As the color changes and shrinkage occurs, move on to the next process and continue until about 270-300 degrees are treated.
Starting slowly and gently – When starting with ECP, until you get your bearings and learn to sweep continuously, it can help to go slowly and focus on a few ciliary processes at a time. I tend to sweep continuously through the sulcus, moving from one ciliary process to the next, adjusting the time spent in front of each ciliary process to allow for the correct level of whitening/shrinkage to occur.
Because eyes have very different sulcus and ciliary process anatomy, what works for one eye may not work for the other. The laser works by targeting the pigment in the ciliary processes, resulting in quicker whitening/shrinkage in more pigmented patients. Simply adjust your duration, proximity and distance to the ciliary process and power. In most cases, you’ll find that you can maintain similar settings and either move closer or farther from the ciliary process or adjust your sweeping speed to titrate treatment. Adjusting the power is always an option as well.
Getting used to endoscopy – One challenge for many surgeons is the new viewing experience of an endoscopic approach. You will get the hang of it pretty quickly, learning to separate what your hands are doing while looking at the display screen. The circulating nurse can help by maintaining the horizon on the screen.
Reducing inflammatory risk – The gentle nature of this technique mitigates postoperative inflammatory risk. Although we carefully minimize over-treatment, ECP does create a small increase in postoperative inflammation compared to phaco alone. Injecting dexamethasone either subconjunctivally or intracamerally at the time of surgery has been shown to be a helpful way to mitigate the early inflammatory risks.3 To reduce long-term inflammatory issues, I alter my normal postoperative steroid routine, maintaining QID dosing of 1% pred acetate for about 1 month, and then slowly tapering. Some surgeons choose to start with a higher dose (like 6x/day pred acetate for 1 week), and then drop to QID for 2 weeks, BID for 2 weeks, etc.
There are many approaches, but the key is to give more steroids short-term with a slower taper, reducing both inflammation and risk of rebound iritis. When we take these extra steps with ECP, the eye generally looks similar to a straight cataract postoperatively, lacking even the short-term hyphema seen with some other MIGS procedures.
An Exciting Future: Exploring Combinations
For me, ECP enables my patients to achieve and maintain target pressures in a minimally invasive way with less long-term reliance on medications and without significant tissue destruction or any hardware in the eye. From my experience, the procedure doesn’t add much time or complications to cataract surgery, and because the postoperative course is similar to standard cataract surgery, ECP generally doesn’t complicate management. As long as we target the correct patients, postoperative visual goals are reached, IOP is stabilized, further glaucomatous nerve damage can be avoided, and most importantly, patients are happy.
One exciting new area of interest is combining ECP with other MIGS outflow procedures like iStent (Glaukos), Hydrus (Ivantis), goniotomy, or ab interno canaloplasty/GATT. Combinations could allow us to both “turn down the faucet” with ECP and “open up the drain” with an angle-based MIGS implant or procedure. It’s just another way that ECP will continue to fit nicely into our armamentarium and expand our options for tailored treatment of glaucoma.
Reference
- Siegel MJ, Boling WS, Faridi OS, et al. Combined endoscopic cyclophotocoagulation and phacoemulsification versus phacoemulsification alone in the treatment of mild to moderate glaucoma. Clin Exp Ophthalmol. 2015 Aug;43(6):531-9.
- Khandan S, Siegel L, Siegel M, Citron M, Siegel M. Long-term Follow-up of Combined Phacoemulsification and Endoscopic Cyclophotocoagulation in the Treatment of Mild to Moderate Glaucoma (abstract). American Glaucoma Society 27th Annual Meeting, March 2-5, 2017.
- Chang DT, Herceg MC, Bilonick RA, Camejo L, Schuman JS, Noecker RJ. Intracameral dexamethasone reduces inflammation on the first postoperative day after cataract surgery in eyes with and without glaucoma. Clin Ophthalmol. 2009;3:345-355. doi:10.2147/opth.s5730
Michael J. Siegel MD, FACS, is an owner/partner at The Glaucoma Center of Michigan in metropolitan Detroit and Co-Chief of the Glaucoma Service and Assistant Professor of Ophthalmology at The William Beaumont School of Medicine at Oakland University, in Royal Oak, Michigan.
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