Focus on Glaucoma

ECP as an option for early intervention

Why patient selection plays a critical role in success rates.

By Robert J. Noecker, MD, MBA

About the Author
	Robert J. Noecker, MD, MBA, is in private practice at Ophthalmic Consultants of Connecticut in Fairfield. His e-mail is noeckerrj@gmail.com. Disclosure: Dr. Noecker disclosed he is a consultant to Endo Optiks.

Research has shown that although cyclophotocoagulation has traditionally been considered as a last resort for glaucoma patients, technological advancements in endoscopic surgery have deemed it to be safe and effective earlier in the surgical management of glaucoma, particularly in comparison to glaucoma filtration surgery.¹

A targeted technique guided with an endoscope, known as endoscopic cyclophotocoagulation (ECP), was introduced in the 1980s. It enables targeted delivery of laser energy precisely and efficiently, which has also allows surgeons to treat eyes with better visual potential. Further, because the surgeon can perform ECP from the same incision as cataract surgery, it can be an adjunct treatment to cataract surgery.

PATIENT SELECTION

Success with ECP begins with identifying the appropriate patient. The treatment population for ECP is broad, as it encompasses those with primary or secondary glaucoma, as well as open or closed angle glaucoma.

Appropriate candidates

ECP is most successful as a first glaucoma procedure in patients who have mild-to-moderate glaucoma and preoperative IOPs between 18 and 30 mm Hg. In those cases, the anatomy is most undisturbed — that is, without synechia or obstacles to visualization.

The following patients can also undergo ECP:

• Pseudophakic or aphakic individuals with uncontrolled glaucoma.

• Post-tube or filtration surgery patients.

• Patients with severe conjunctival scarring and failed filtration surgeries.

• Patients unsuitable for filtration surgery because they have chronic ocular surface disease or high complication risks.

Those with cataract and uncontrolled glaucoma or controlled glaucoma can undergo combined phaco-ECP if they want to reduce their medications, or if they have cataract and narrow-angle glaucoma with a plateau iris or cataract and high-risk ocular hypertension.¹

Not suitable for ECP

Phakic individuals are poorer candidates for ECP. Performing thorough ECP on a patient whose natural lens is intact can be difficult, although not impossible. I proceed with caution on children, because their anatomy is crowded and they are prone to developing hypotony.

Neovascular glaucoma patients are also challenging candidates for ECP, because the view to the ciliary processes may be blocked anteriorly and their aqueous production may be suboptimal.

Further, exfoliation patients’ ciliary processes are not well pigmented and fail to absorb the laser as well as primary open-angle glaucoma patients. Collectively, these groups make up a small percentage of the glaucoma population.

SURGICAL COURSE

How ECP influences aqueous production

The surface of the ciliary body is covered by non-pigmented and pigmented ciliary epithelium. ECP targets the pigmented ciliary epithelium that is juxtaposed to the non-pigmented epithelium that produces the aqueous humor. The pigment absorbs the light energy and transforms it into heat, killing proximal cells that produce aqueous humor, and, in turn, reducing aqueous production to lower IOP.

The endoscopic laser application only treats tissue superficially and locally, avoiding destruction to structures of the eye. ECP differs from filtration procedures in that ECP is designed to reduce aqueous production while filtration procedures are designed to increase aqueous outflow by draining the eye. Consequently, a patient can have ECP after a failed filtration procedure because ECP has its approach on the opposite end of the spectrum.

Figure. Endoscopic view of ciliary processes shows the aiming beam of the laser (red light) on the location of treatment. This patient has plateau iris configuration in which the ciliary processes are prominent anteriorly.

Viscoelastic and incisions

At the start of ECP from an anterior approach, I use a the viscoelastic Healon GV (Abbott Medical Optics, Abbott Park, Ill.) because it does not drain out of the eye easily with manipulation. It is also easy to remove with irrigation and aspiration.

I then make two incisions the size of a primary cataract incision with the keratome. I inflate the sulcus to 180° at a time. I make the incision at the second site superonasally so that I have two sites in which to insert the laser probe. My goal is to paint over the entire region of the ciliary process and expose it to laser energy.

Applying laser pulses

Importantly, I do not target the processes one by one. I also make an effort not to laser the back of the iris because that can cause inflammation and irregular pupil postoperatively. After I treat 180° to 240°, I remove the probe and inflate the sulcus underneath the opposite incision.

I then treat through the second incision for a total of 360° to lower IOP maximally. To avoid popping in the ciliary processes and, ultimately, inflammation, I apply the laser slowly and steadily.

When operating on patients with small pupils, I employ a pupil expansion device to avoid hitting the iris with the ECP probe, which can also lead to inflammation or pigment dispersion.

Postoperative course

The patient returns on postoperative day one, and I prescribe brimonodine (Alphagan P, Allergan, Irvine, Calif.) to prevent IOP spikes. I then instruct the patient to apply routine drops for cataract surgery, such as antibiotics, steroids and NSAIDs.

The patient returns for a follow-up visit one week postoperatively, and I discontinue all medication with the exception of the steroids, which the patient may remain on for approximately an additional month.

“A patient can have ECP after a failed filtration procedure because ECP has its approach from the opposite end of the spectrum.”

CASE STUDY

Clinical presentation

A 63-year-old Asian woman with narrow angles and plateau iris configuration presented with an episode of angle closure in the left eye, which was treated successfully with laser iridotomy (Figure).

The patient was hyperopic with a +4.00 sph refraction OU. Dense cataracts were present and visual acuity was 20/50 OD and 20/80 OS. IOPs measured 19 OD and 25 OS following laser peripheral iridotomies OU and use of travoprost (Travatan Z, Alcon, Forth Worth, Texas) and timolol–brimonidine (Combigan, Allergan) fixed combination ophthalmic eyedrops.

Pachymetry was 540 OU. The angle was open but narrow OD and was still narrow OS with scattered peripheral anterior synechiae OS. Optic nerves had moderate cupping with some inferior thinning OD and rim loss OS with corresponding retinal nerve fiber layer thinning revealed on OCT and peripheral vision loss revealed on visual fields.

ECP performed

The patient underwent phaco-ECP in the left eye to reduce IOP and improve visual acuity. I performed ECP through two incisions over 360° of ciliary processes, using settings of 0.25 watts under continuous mode.

I applied laser pulses to the ciliary processes until they showed shrinkage and whitening. No pops were noted.

Postoperative course

Postoperatively, the patient applied steroids, NSAIDs and antibiotic drops QID. Visual acuity was 20/30 on postoperative day one with IOP of 20 mm Hg.

At one month after tapering the drops, her visual acuity was 20/25 uncorrected and IOP was 16 mm Hg off medication.

I performed the same procedure in the fellow eye with successful IOP lowering to 15 mm Hg off eyedrops and visual acuity of 20/20 after one month.

CONCLUSION

ECP performed on its own or as an adjunct to cataract surgery is proven to be safe and effective with few complications. Like all glaucoma procedures, once a surgeon has mastered his or her routine, performing ECP becomes second nature.

Comfort in performing the ECP procedure provides us the ability hone our skills in selecting the best candidates possible. Although ECP is a versatile procedure that can be performed at any stage of the surgical glaucoma treatment algorithm, it is most successful in early stage, mild to moderate glaucoma patients. OM

REFERENCE