How to perform the three-in-one ICE procedure

Combined iStent, cataract and ECP may yield lower IOP with fewer risks than other interventions for glaucoma.

By Parag D. Parekh, MD

For glaucoma patients in whom medications or laser treatment have not lowered IOP adequately, the only option has been invasive surgery, such as trabeculectomy or tube shunt, both of which carry a high risk of complications. Other procedures, such as canaloplasty or trabectome, can be difficult to perform with significant complication rates or limited effectiveness.

However, now a newer procedure may help these patients, and it is done in conjunction with cataract surgery. In some cases, these patients may avoid a trabeculectomy or tube altogether. It’s called ICE, for iStent + cataract + endoscopic cyclophotocoagulation. Here, I will review how to perform this procedure and manage patients.

THREE PROCEDURES IN ONE

How iStent works

The FDA approved the iStent trabecular Micro-Bypass (Glaukos, Laguna Hills, Calif.), a 1-mm titanium implant for use in conjunction with cataract surgery, in 2012. Using an inserter and intraoperative gonioscopy, we essentially can bypass the trabecular meshwork to improve aqueous outflow. Draining aqueous directly into Schlemm’s canal helps lower IOP.

The iStent Trabecular Micro-Bypass stent (Glaukos, Laguna Hills, Calif.) is a 1-mm titanium implant used in conjunction with cataract surgery.
COURTESY: GLAUKOS

iStent is indicated for patients with mild to moderate open-angle glaucoma. In certain instances, I have used the iStent off-label in patients who are already pseudophakic and have failed SLT and topical drugs.

Studies have shown a significantly higher percentage of patients who received the iStent combined with phacoemulsification had unmedicated IOP less than 21 mm Hg than those who had phacoemulsification alone, and the safety profiles were comparable.^1-3 Data on ICE was presented at the recent American Glaucoma Society meeting and the recent ASCRS meeting.

ECP in cataract

Meanwhile, studies have shown that endoscopic cyclophotocoagulation (ECP), combined with cataract surgery can also significantly lower IOP.^4,5 ECP allows for accurate localization and precise titration of laser delivery to the ciliary processes, thus decreasing aqueous inflow. The instrument combines a light source, endolaser, and video endoscope in a 20-gauge single probe.

Combining the iStent and ECP in a single procedure, in conjunction with cataract surgery, will help treat both sides of the “glaucoma equation,” namely inflow and outflow. My results have been good enough that I usually offer it as first-line glaucoma surgery before tube placement or trabeculectomy. ICE has a much better safety profile than trabeculectomy or tube shunt surgery.

PERFORMING THE PROCEDURE

First, gonioscopy

Before surgery, the manufacturer of iStent recommends doing gonioscopy to rule out peripheral anterior synechiae, rubeosis and other abnormalities that cause poor visualization of the angle, which could lead to improper iStent placement.

The first step is to perform the clear corneal cataract surgery as you normally would from a temporal approach. Once you’ve inserted the IOL, inflate the sulcus with viscoelastic. You then can perform ECP through the main incision. I usually treat about 220° of ciliary processes.

Once you complete ECP, aspirate the viscoelastic, taking care to remove as much from the sulcus as possible. Once the viscoelastic is extracted, instill Miochol (acetylcholine, Bausch + Lomb, Bridgewater, N.J.) or Miostat (carbachol, Alcon, Forth Worth, Texas) into the anterior chamber to constrict the pupil. Then re-inflate the eye with viscoelastic and place some viscoelastic on the cornea to help with coupling of the gonioprism.

Placing the iStent

Tilt the patient’s head and the microscope at a steep angle away from you. To confirm that you’ve rotated the patient’s head enough, place a gonioprism on the cornea and check to make sure you have a good view of the trabecular meshwork. Also, increase slit lamp magnification to 8 x to 10 x, and increase the illumination. Without a good view of the trabecular meshwork, successfully place the iStent can be very difficult.

Once you’re comfortable with the view, place the iStent inserter into the anterior chamber. Gently advance the iStent device into the pigmented trabecular meshwork and release the iStent. To confirm proper placement, “strum” the iStent with the cannula; the device should move slightly, then immediately return to its original position. If not positioned properly, you can regrasp it with the inserter and try to place it again in a different area of trabecular meshwork. (You may see a small reflux of blood. If blood obscures the view, “push” it away with viscoelastic.)

Next, rotate the patient’s head and microscope back to the initial position. Using the irrigation-aspiration probe, remove the viscoelastic and seal the incision as usual.

POSTOPERATIVE CARE

Avoiding postoperative IOP spikes

Any time I perform ECP, I inject a small amount of subconjunctival steroid to avoid postoperative inflammation. I also examine the patient at the slit lamp and release some fluid from the side port incision to reduce postoperative IOP spikes that can occur due to retained viscoelastic in the sulcus.

Postoperatively, I follow my typical post-cataract regimen. I prescribe a topical steroid and NSAID, plus a topical antibiotic for prophylaxis. (Remember, antibiotics for postsurgical prophylaxis are considered an off-label use.)

Follow-up visits take place at one day and one week postoperatively. During this period, IOP may fluctuate due to steroid use and viscoelastic issues. As the IOP improves, the patient may reduce his or her dependence on glaucoma drops.

SUMMARY

In the past, we had few alternatives for treating glaucoma refractory to SLT or IOP-lowering agents. With ICE, however, we can combine cataract surgery with a minimally invasive glaucoma procedure for a low-risk and potentially high-impact improvement in IOP. Some of these patients may go on to need a trabeculectomy or tube shunt later, but I feel it’s important to offer the procedure with the better side effect profile first, given the risks, side effects and complications that often come with the alternatives. OM

REFERENCES

About the Author
	Parag Parekh, MD, is in private practice with Laurel Eye Clinic in Brookville, Pa. He has performed significant clinical research, and has written numerous scientific articles and textbook chapters. His e-mail is parag2020@gmail.com. Disclosure: Dr. Parekh is a speaker for Bausch + Lomb, Allergan and Alcon.