CASE STUDY

Endocyclophotocoagulation:

A Valuable Diagnostic Tool

BY MALIK KAHOOK, M.D.

Endocyclophotocoagulation (ECP) is an increasingly utilized method of cycloablation performed with an 810-nm diode laser, a 175-W Xenon light source and a heliumneon laser-aiming beam (Endo Optiks, Little Silver, N.J.). The endoscope allows for direct visualization of intraocular structures for either laser treatment and/or for diagnostic purposes.

We have found ECP to be invaluable in cases of patients undergoing corneal transplantation for opacified corneas who also require an IOP-lowering procedure. The real-time view in the operating room allows the surgeon to quickly assess the status of the anterior chamber, including anatomy of the drainage angle and iris, as well as condition of the lens in phakic and pseudophakic patients. A decision can then be made to perform ECP in those patents with normal anterior-segment anatomy or glaucoma drainage device implantation in those with compromised drainage angles or inadequate visualization of the cilliary processes.

Case Presentation

We recently had a 74-year-old female patient with a history of herpes simplex virus keratopathy of the left eye that required initial corneal transplantation 15 years ago. Since then, she has required two other corneal transplantations, both ending with rejection and opacification of her cornea. Little else was known about her history, and medical records from outside our state were not available. She presented to our cornea service for possible corneal prosthesis surgery at which time her vision was noted to be 20/HM. IOP was 28 mm Hg and there was no view of the anterior chamber. B-scan revealed an IOL implant with a flat retina and no intraocular anatomical disruption. She was scheduled for Boston Keratoprosthesis ([KPro], Massachusetts Eye and Ear Infirmary, Boston) surgery with combined ECP (for both therapeutic and diagnostic purposes). She also consented to a glaucoma drainage device (GDD) implantation, if needed.

Figure 1. ECP treatment with a curved probe.

Treatment and Evaluation

The procedure began with an inferior paracentesis, followed by temporal clear corneal incision to accommodate entry of the 20-gauge endoprobe. Under endoscopic visualization, the patient was noted to have normal iris anatomy with an open drainage angle. She had a well-centered posterior chamber IOL. After injection of Healon GV (Advanced Medical Optics, Santa Ana, Calif.) underneath the iris, ECP treatment with a curved probe (Figure 1) was completed for 270° with 0.25 W of energy set on continuous mode (Figure 2). A second clear corneal incision was constructed 100° away followed by treatment of the subincisional ciliary processes. Once this was complete, two interrupted 10-0 nylon sutures were placed in each of the clear cornea wounds and the patient then underwent uneventful transplantation of a KPro. On last follow-up, 6 months postoperatively, the patient's IOP remained controlled at 17 mm Hg and her vision had improved to 20/60.

Figure 2. ECP treatment with a curved probe was completed for 270° with 0.25 W of energy set on continuous mode.

ALL IMAGES COURTESY OF THE AUTHOR.

Discussion

Post-penetrating keratoplasty glaucoma represents a very difficult surgical dilemma for the surgeon. Increased IOP is often present in the setting of diffuse anterior synechiae and compromised drainage angle. The challenge is increased even more in those patients with failed corneal grafts that have become opacified, thus prohibiting direct visualization of anterior chamber, structures. While B-scan ulstrasonography and anterior segment, OCT can shed light on the status of the intraocular structures, direct visualization is often required to truly understand the pathology at hand.

ECP is an important part of my surgical algorithm (Table). While the focused ablation has been proved to be effective in lowering IOP,^1-6 we have found the use of the endoscope for diagnostic purposes prior to laser ablation invaluable. The above case illustrates an important advantage for assessing the anterior segment prior to performing IOP-lowering surgery. My typical approach in patients with corneal transplants is to implant a GDD through the pars plana, through the sulcus or anteriorly if a posterior approach is not possible. Unfortunately, GDD implantation in those with corneal transplants carries the added risk of donor cornea edema or rejection. Patients with normal anterior-segment anatomy (with minimal anterior synechiae) and accessible cilliary processes can benefit from ECP while avoiding the need for a permanent GDD implant. OM

References

1. Gayton JL, Van Der Karr M, Sanders V. Combined cataract and glaucoma surgery: trabeculectomy versus endoscopic laser cycloablation. J Cataract Refract Surg. 1999;25:1214-1219.
2. Lima FE, Magacho L, Carvalho DM, et al. A prospective, comparative study between endoscopic cyclophotocoagulation and the Ahmed drainage implant in refractory glaucoma. J Glaucoma. 2004; 13:233-237.3.
3. Chen J, Cohn RA, Lin SC, et al. Endoscopic photocoagulation of the ciliary body for treatment of refractory glaucomas. Am J Ophthalmol. 1997;124:787-796.
4. Neely DE, Plager DA. Endocyclophotocoagulation for management of difficult pediatric glaucomas. JAAPOS. 2001;5:221-229.
5. Barkana Y, Morad Y, Bennun J. Endoscopic photocoagulation of the ciliary body after repeated failure of trans-scleral diode-laser cyclophotocoagulation. Am J Ophthalmol. 2002;133:405-407.
6. Kahook MY, Lathrop KL, Noecker RJ One-site versus two-site endoscopic cyclophotocoagulation. J Glaucoma. 2007;16:527-530.

Malik Y. Kahook, MD, is assistant professor and director of clinical research in the Department of Ophthalmology at the University of Colorado at Denver & Health Sciences Center. He acknowledged no financial interest any product or company mentioned herein. Dr. Kahook may be reached at (720) 848-5029; malik.kahook@gmail.com.