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  • The Role of Endoscopic Cyclophotocoagulation in Pediatric Glaucoma Patients

    Pediatric Ophth/Strabismus
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    Endoscopic cyclophotocoagulation (ECP) has become an invaluable tool in the management of pediatric glaucoma patients. This revolutionary technology permits the controlled destruction of ciliary body processes with minimal risk of inducing hypotony, the most feared and irreversible complication of ciliary body destruction. As a result of ECP’s favorable safety profile, its use as an adjunctive therapy in difficult or refractory pediatric glaucoma patients has been steadily growing. This article reviews appropriate technique and firsthand experience in treating more than 70 patients with almost 13 years of follow up.1-3

    Technology and Technique

    Originally developed and applied by Uram in the early 1990s as a technique for treating dismal cases of neovascular glaucoma, ECP is increasingly used in a diverse range of glaucomas in both adult and pediatric populations (Ophthalmology. 1992;99(12):1823–1828). The technology uses a 20-gauge, triple-function handpiece with fiber optics for a halogen light source, video camera monitoring, and a 810-nm diode laser-treatment delivery with a 670-nm diode laser aiming beam (Figures 1 and 2). This handpiece is available in both straight and curved models. The curved one has the advantage of being able to treat a wider arc of ciliary processes through a single incision. The device may be used in both phakic and aphakic/pseudophakic patients, but it is perhaps best suited to the latter, given the legitimate risks of secondary cataract formation, typically a posterior subcapsular cataract or an anterior capsular rupture from direct contact with the tip of the probe.
    Image courtesy Daniel Neely, MD.
    Figure 1. Triple-function fiber-optic handpiece.
    Image courtesy Daniel Neely, MD.
    Figure 2. Untreated, illuminated ciliary processes.

    The surgeon usually places the probe into the anterior chamber through 1 or 2 limbal incisions created with either a 2.5-mm keratome or a 19-gauge MVR blade placed through the cornea just anterior to the limbus, although the technique may also be done via a pars plana incision. If 2 corneal incisions are used, they are best placed 90° apart to facilitate access to a wide arc of ciliary body. The anterior chamber is maintained either with a continuous infusion or by placement of a viscoelastic. The use of viscoelastic is particularly helpful if one needs to lyse posterior synechiae or open the ciliary sulcus. If the patient is phakic, its use is critical in order to push the lens posteriorly to avoid contact with the anterior capsule.

    Under the operating microscope, the handpiece is placed into the eye and is directed across the anterior chamber and underneath the iris to reach the ciliary processes. The surgeon, who now views the procedure on a television monitor attached to the laser, is able to identify and treat individual ciliary processes (Figure 3). Typical treatments consist of a power setting of 300 mW (200–800 mW) applied in a continuous mode of 1–2 seconds’ duration until a visible whitening and contracture of the entire ciliary process occurs. Power is titrated down if rupture of the ciliary process occurs, as this may lead to excessive postoperative inflammation and hyphema. Working first in 1 direction and then in the opposite, the surgeon is able to treat a wide arc of ciliary processes and may even treat the intervening “valleys” of pigmented ciliary epithelium (Figure 4). The arc of treatment is typically a minimum of 180° up to a maximum of 270°, which is possible through a single incision when using the curved handpiece. Postoperatively, patients are placed on a combination antibiotic/steroid 4 times daily along with atropine 1% once daily for several weeks.
    Image courtesy Daniel Neely, MD.
    Figure 3. Untreated (left) and treated (right) ciliary processes.
    Image courtesy Daniel Neely, MD.
    Figure 4. Fully treated ciliary processes.

    Patients and Outcomes

    While ECP may be used to treat a wide range of pediatric glaucomas including refractory congenital glaucoma, glaucoma associated with Sturge-Weber syndrome (and glaucoma secondary to aniridia), microphthalmia, and anterior segment dysgenesis, it is perhaps most valuable in the management of aphakic/pseudophakic glaucoma that commonly develops following cataract surgery in children. When looking at this diverse population of patients, I have found that in general, ECP is able to produce a sustained 40% decrease in intraocular pressures. In a 2005 review of 64 ECP procedures performed on 46 pediatric eyes with a variety of glaucoma diagnoses, Brooks, Neely, and Plager found that the pretreatment mean IOP of 35.0 ± 8.0 was subsequently lowered to 21.4 ± 10.0 at 41.4 ± 33.2 months of follow up (Nova Science Publishers; 2005:279–294). Re-treatments are common, and in this study, 30% of patients were re-treated at least once. Cumulative success rate was 42% after an average of 1.4 ± 0.8 treatments covering a total arc of 258 ± 55 degrees of ciliary body. In the subset of aphakic/pseudophakic patients, the success rate is even higher at almost 53%; this finding is particularly significant given that these patients are notoriously difficult to treat when medical options prove to be inadequate (J AAPOS. 2007;11(1):34–40). Postoperative complications do occur and have included retinal detachment in 2 patients and hypotony in 1 patient who received a modest treatment of only 180°. Despite the possibility of inducing hypotony, it remains, fortunately, an uncommon event even when the ciliary processes are treated extensively. In a recent study that included 8 aphakic/pseudophakic pediatric eyes treated over an arc of 360° during multiple ECP sessions, none of the patients developed secondary hypotony (J AAPOS. 2007;11(1):34–40).

    It should be emphasized that ECP is not recommended as a primary treatment modality for patients with congenital glaucoma. These patients have an inherent angle dysgenesis, and for any treatment modality to be successful, it must be directed at improving aqueous outflow rather than decreasing its production. Angle surgery such as goniotomy or trabeculotomy remains the treatment of choice for congenital glaucoma. If several attempts to open the angle have failed or been only partially successful, these patients are then considered for secondary procedures including not only ECP but also trabeculectomy or placement of a tube-shunt implant.

    Summary

    Endoscopic cyclophotocoagulation is an effective treatment option for pediatric patients with difficult or refractory glaucoma. It has been shown to have a moderately good success rate along with a low incidence of significant complications, particularly with regard to avoiding secondary hypotony. ECP does not replace traditional angle surgery for children with primary infantile or congenital glaucoma.

    References

    1. Plager DA, Neely DE. Intermediate-term results of endoscopic diode laser cyclophotocoagulation for pediatric glaucoma.J AAPOS. 1999;3(3):131–137.
    2. Neely DE, Plager DA. Endocyclophotocoagulation for management of difficult pediatric glaucomas.J AAPOS. 2001;5(4):221–229.
    3. Carter C, Plager DA, Neely DE, et al. Endoscopic diode laser cyclophotocoagulation in the management of aphakic and pseudophakic glaucoma in children. J AAPOS. In press.
    4. Uram M. Ophthalmic laser microendoscope ciliary process ablation in the management of neovascular glaucoma.Ophthalmology. 1992;99(12):1823–1828.
    5. Brooks JA, Neely DE, Plager DA. An update on endocyclophotocoagulation for management of pediatric glaucomas. In: Reece SM, ed. Focus on Glaucoma Research. New York, NY: Nova Science Publishers; 2005:279–294.
    6. Carter BC, Plager DA, Neely DE, Sprunger DT, Sondhi N, Roberts GJ. Endoscopic Diode Laser Cyclophotocoagulation in the Management of Aphakic and Pseudophakic Glaucoma in Children.J AAPOS. 2007;11(1):34–40.

    Author Disclosure

    The author states that he has no financial relationship with the manufacturer or provider of any product or service discussed in this article or with the manufacturer or provider of any competing product or service.