Skip to main content

  • Endoscopic Cyclophotocoagulation for Glaucoma

    Glaucoma
    Add to My Bookmarks

    Endoscopic cyclophotocoagulation (ECP) has been increasingly used as a primary surgery for the treatment of glaucoma. A recent multicenter study demonstrated a reduced need for glaucoma medications in patients who underwent combined ECP and phacoemulsification cataract extraction procedures compared to those treated with cataract surgery only.1 However, caution is warranted in the use of cyclodestruction, such as ECP, as a first-line surgical therapy.

    Background on Cyclodestructive Procedures

    Cyclodestructive procedures are usually reserved for cases of glaucoma that are refractory to medical therapy, outflow surgeries, and eyes that have little or no visual potential. These procedures are traditionally carried out using laser energy via a transscleral route, a process known as transscleral cyclophotocoagulation (TCP). More recently, ECP has become an increasingly important weapon in the glaucoma surgeon's armamentarium for the treatment of refractory glaucomas1,2 and may have distinct advantages over the transscleral approach in eyes with visual potential. Under direct endoscopic guidance, ECP treatment of ciliary processes can be titrated to achieve shrinkage and whitening without excessive damage or injury to adjacent tissues.

    ECP Technique

    The laser unit for ECP, E2 (Endo Optiks, Inc., Little Silver, NJ), incorporates a diode laser that emits pulsed continuous-wave energy at 810 nm, a 175-W xenon light source, a helium-neon laser aiming beam, and video camera imaging that can be recorded (Figure 1). All four elements are transmitted via fiberoptics to an 18- or 20-gauge probe (Figure 2) that is inserted intraocularly. Procedures are carried out  while viewing the ciliary processes on the unit's monitor.

    Courtesy of Shan C. Lin, MD
    Figure 1. Laser and monitor for endoscopic cyclophotocoagulation.

    Courtesy of Shan C. Lin, MD
    Figure 2. 20-gauge laser probe for endoscopic cyclophotocoagulation.

    The two main approaches to reach the ciliary processes are via a limbal or pars plana entry. Through a single incision, an approximately 180-degree span of ciliary processes can be photocoagulated. (A larger area can be treated if a curved probe is used.) Laser energy is applied to each process until shrinkage and whitening occur (Figure 3). Typically, an area between 180 and 360 degrees is treated.2,3 The author's preference is to treat 270 to 360 degrees of processes.

    Courtesy of Shan C. Lin, MD
    Figure 3. Endoscopic view of ciliary processes. Processes on the left have been treated and show whitening and shrinkage compared to untreated processes on the right.

    ECP Efficacy and Safety

    In the largest study published on ECP, the mean intraocular pressure (IOP) drop was 10.7 mmHg (34% mean reduction) after a follow-up period of 12.9 months. Glaucoma medication usage was reduced from an average of 3.0 preoperatively to 2.0 postoperatively.2 However, complications included fibrin exudate in 24% of patients, hyphema in 12%, cystoid macular edema (CME) in 10%, vision loss of two lines or greater in 6%, and choroidal detachment in 4%.

    The authors of a randomized trial comparing ECP to Ahmed valve surgery for refractory glaucoma found that the two procedures had similar efficacy for reducing IOP.3 The overall complication rate was higher in the Ahmed valve group; notable complications in the ECP group were retinal detachment, hypotony, and phthisis bulbi.

    Researchers who conducted the study comparing the combined phacoemulsification-ECP procedure to cataract surgery followed up with patients for a mean of 31.2 months. Results of the study, which was supported by Endo Optiks,1 indicated that IOP reduction was slightly greater in the phacoemulsification-ECP group (2.2 mmHg) than in the phacoemulsification only group (0.9 mmHg). The reduction in the number of medications used was significantly greater in the combined surgery group (1.51) compared to the phacoemulsification only group (0.03). There were no serious complications in either treatment arm, and complication rates were similar between the two groups. The CME rate was 0.8% in the phacoemulsification-ECP group and 0.7% in the phacoemulsification only group.

    ECP Indications

    The indications for performing ECP include types of glaucoma, such as primary open-angle, pseudoexfoliation, neovascular, pediatric, and angle-closure, that have been refractory to medical or filtering surgery.2,3

    Eyes with relatively intact central visual acuity may be appropriate candidates for ECP. However, since decreases in IOP with ECP appear modest, eyes with highly elevated pressure may be more appropriate candidates for TCP, particularly if postsurgical visual potential is limited. Filtration surgery is still the procedure of choice for eyes with excessively high IOP and intact vision. These recommendations are based, in part, on the experience of the author, as there are no studies that directly compare ECP to TCP or trabeculectomy.

    As described above, ECP has also been used in conjunction with cataract extraction as a primary glaucoma surgery. There may be significant concerns with the indiscriminant use of ECP in all glaucoma patients who are undergoing cataract extraction. ECP has the potential for serious adverse events, including CME, retinal detachment, hypotony, and phthisis bulbi.2,3 Furthermore, there is a significant learning curve for the procedure, and inexperienced surgeons may encounter intraoperative complications more frequently than those who have become facile. Finally, the long-term efficacy of glaucoma surgery is usually measured after around five years; I await such results for ECP.

    Summary

    ECP is a handy addition to the glaucoma surgeon's toolbox for treating various forms of glaucoma, particularly in cases in which other types of surgery have failed or are not feasible. Clinicians should be cautious in adopting this new procedure as a primary surgery for treating cases of medically controlled glaucoma.

    References

    1. Berke SJ, Sturm RT, Caronia RM, Nelson DB, D'Aversa G, Freedman M. Phacoemulsification combined with Endoscopic Cyclophotocoagulation (ECP) in the Management of Cataract and Medically Controlled Glaucoma: A Large, Long Term Study [abstract]. Final Program and Abstract Book: American Glaucoma Society 16th Annual Meeting, 2-5 March 2006. Charleston, S.C. Abstract 22:47.

    2. Chen J, Cohn RA, Lin SC, Cortes AE, Alvaraddo JA. Endoscopic photocoagulation of the ciliary body for treatment of refractory glaucomas. Am J Ophthalmol. 1997;124:787-796.

    3. Lima FE, Magacho L, Carvalho DM, Susanna R Jr, Avila MP. A prospective, comparative study between endoscopic cyclophotocoagulation and the Ahmed drainage implant in refractory glaucoma. J Glaucoma. 2004;13:233-237.

    Author Disclosure

    Dr. Lin states that he has no financial relationship with the manufacturer of any product discussed in this article or with the manufacturer of any competing product.