Comparison of the Effectiveness and Safety of Transscleral Cyclophotocoagulation and Endoscopic Cyclophotocoagulation in Pediatric Glaucoma Courtney L. Kraus, MD; Lawrence Tychsen, MD; Gregg T. Lueder, MD; Susan M. Culican, MD, PhD
ABSTRACT Purpose: Among the options for surgical management of pediatric glaucoma, destruction of the ciliary body reduces aqueous production and, consequently, intraocular pressure (IOP). Compared to more invasive filtering and shunt procedures, cyclodestruction is an attractive option for control of IOP in pediatric glaucomas. Methods: The relative reduction in IOP, duration of effect, and comparable safety and efficacy of transscleral cyclophotocoagulation (TSCP) and endoscopic cyclophotocoagulation (ECP) in pediatric patients with glaucoma was studied in this retrospective chart review.
erage of 2.29 cyclodestructive treatments. These differences were not statistically significant. A final success rate of 67.6% after TSCP and 62% after ECP failed to significantly differ between the two groups. Consequently, two-thirds of the patients were able to avoid penetrating surgery and the associated risks after one or more cyclodestructive procedures. Conclusions: TSCP and ECP are safe, effective, and comparable treatments for pediatric glaucomas. The results suggest that TSCP and ECP may be considered first-line therapy to achieve control of IOP in all forms of pediatric glaucoma.
Results: A reduction in IOP of 28.6% and 33.2% with TSCP and ECP, respectively, was found. Eyes treated with ECP underwent an average of 3.24 cyclodestructive procedures; eyes treated with TSCP underwent an av-
[J Pediatr Ophthalmol Strabismus 2014;51(2):120127.]
INTRODUCTION Pediatric glaucoma accounts for up to 10% of all cases of blindness in children.1 The pediatric glaucomas are a heterogeneous group, including both primary and secondary causes. Primary congenital glaucoma occurs within the first few years of life, represents the most common cause of glaucoma in childhood, and is caused by abnormal development of the anterior chamber angle and subsequent
impaired aqueous outflow. In secondary glaucoma, aqueous outflow is reduced due to either a congenital or an acquired ocular disease or systemic disorder, including inflammatory, neoplastic, hamartomatous, metabolic, or congenital abnormalities.2 Pediatric glaucoma is a challenging disorder to treat, with management being primarily surgical. In contrast to adults, topical medications are traditionally more of a temporizing measure. Given the chal-
From the Department of Ophthalmology and Visual Sciences, Washington University School of Medicine (CLK, LT, GTL, SMC); and the St. Louis Children’s Hospital, St. Louis, Missouri (LT, GTL, SMC). Submitted: September 16, 2013; Accepted: November 19, 2013; Posted online: February 18, 2014 The authors have no financial or proprietary interest in the materials presented herein. Correspondence: Courtney L. Kraus, MD, 660 S. Euclid Ave., St. Louis, MO 63110. E-mail: [email protected] doi: 10.3928/01913913-20140211-01
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lenge of instilling drops in this age group, their limited efficacy, frequent dosing, and restrictions on use of certain medications (ie, brimonidine), attempts to treat exclusively with drops are generally unsuccessful. Additionally, traditional surgical interventions used in adult patients with glaucoma (laser trabeculoplasty and trabeculectomy) have their own limitations. Laser trabeculotomy is impossible in an uncooperative child, whereas trabeculectomy has risks such as late bleb-related infection, hypotony, and phthisis.3 Destruction of the ciliary body serves to reduce aqueous secretion and, consequently, intraocular pressure (IOP). A variety of cyclodestructive procedures have been used to reduce aqueous production, including cyclocryotherapy and Nd:YAG, argon, and diode thermal lasers.4 Historically, cyclodestructive procedures have been reserved for adult patients who have elevated IOP and failed trabeculectomy or tube shunts, limited visual potential, or painful eyes. Because these techniques are less invasive than filtering surgery, minimizing both immediate postoperative complications and lifetime risk of blebitis/endophthalmitis, their use in children is particularly attractive. Beckman et al.5 and Beckman and Sugar6 first described the use of transscleral cyclophotocoagulation (TSCP). It is a noninvasive cyclodestructive technique where transscleral application of infrared light is absorbed by the pigmented epithelial cells of the ciliary body, causing destruction of ciliary body epithelium and coagulation necrosis of ciliary body.7 In contrast, endoscopic cyclophotocoagulation (ECP) allows direct visualization of the ciliary processes and precise treatment using a diode laser emitting infrared light. Using a lower energy and more accurately targeting the tissue than transscleral procedures, ECP may increase the success of cycloablation while decreasing complications such as visual loss and phthisis.8 The safety and efficacy of TSCP and ECP have been studied in the pediatric population and both have reportedly been successful at lowering IOP. However, the relative reduction, duration of effect, and comparable safety and efficacy of each technique has not been performed. The purpose of this study was to compare the efficacy of TSCP and ECP in controlling IOP in pediatric patients with glaucoma. PATIENTS AND METHODS A retrospective analysis was conducted of the outcomes of eyes being treated for glaucoma using
cyclophotocoagulation by three surgeons (LT, GTL, SMC). The Institutional Review Board of the Human Research Protection Office of Washington University, St. Louis approved this study. All patients were younger than 18 years and undergoing either TSCP or ECP for treatment of glaucoma at St. Louis Children’s Hospital from 1995 to 2007. Causes of glaucoma included aphakia, pseudophakia, aniridia or anterior segment dysgenesis, Sturge–Weber disease, uveitis, trauma, retinopathy of prematurity (ROP), and congenital glaucoma. Measurable outcomes such as reduction in IOP, avoidance of additional glaucoma procedures, ability to discontinue drop therapy, and better control with synergistic pharmaceutical therapy were examined. Additionally, safety and frequency of adverse outcomes following the two procedures were analyzed. Comparison of efficacy was of particular interest and was assessed using the number of subsequent cyclodestructive events per eye, time to next surgery (cyclodestructive, tube shunt, or filter), and mean IOP reduction. The initial and follow-up treatments of a child’s glaucoma were determined on a case-by-case basis. Decisions to add medication or perform surgery were made by the individual surgeon and based on persistently elevated IOP, optic nerve change, or observed myopic shift. Surgical management was pursued according to what procedure was believed to be in the best interest of the child and could include cyclophotocoagulation, tube shunt, or filtering. Whether a patient underwent TSCP or ECP was left to the discretion of the individual surgeon. Patient data collected from the preoperative and postoperative visits included IOP, visual acuity, and the number of glaucoma medications required. Prior glaucoma procedures such as goniotomy, trabeculotomy, trabeculectomy, and tube shunts were recorded. The choice of cyclodestructive procedure was at the surgeon’s discretion. Several eyes underwent multiple cyclodestructive treatments. For TSCP treatments, power ranged from 1,500 to 2,000 mW with a duration time of 2,000 ms, treating 90° to 360°. The probe was placed at the limbus with adjustment of treatment parameters based on the occurrence of “pops” (adjusted down on power for consecutive “pops”). For ECP treatments, an operating microscope was employed and a limbal incision was created. In phakic patients, special care was taken to avoid the anterior lens capsule. The ophthalmic laser microendoscope was
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TABLE 1
TABLE 2
Categories of Glaucoma and No. Undergoing ECP and TSCP as First Cyclodestructive Procedure for IOP Control
Treatment Preceding Cyclophotocoagulation Variable
Category
ECP
TSCP
No. of preceding surgeries
Aphakic
12 (23%)
18 (25%)
0
63
Pseudophakic
12 (23%)
10 (14%)
1
27
Congenital
No. of Patients
11 (22%)
21 (29%)
2
15
Anterior segment dysgenesis
4 (8%)
5 (7%)
3
10
Aniridia
5 (9%)
1 (1%)
4
7
Sturge–Weber
5 (9%)
5 (7%)
Trauma
2 (4%)
5 (7%)
Retinopathy of prematurity
1 (1%)
3 (5%)
Uveitis
1 (1%)
1 (1%)
Other
1 (1%)
2 (2%)
Total
52
72
ECP = endoscopic cyclophotocoagulation; TSCP = transscleral cyclophotocoagulation; IOP = intraocular pressure
then inserted into the anterior chamber and directed through the pupil to access the ciliary body and ciliary processes. Using fiberoptic video images, individual ciliary processes were identifiable for photocoagulation. One or two pulses of 400 to 800 mW were applied for 1 to 2 seconds until visible whitening and contracture of the ciliary process occurred; 90° to 360° of contiguous ciliary processes were treated in this manner. Postoperative medications included an antibiotic-steroid preparation taken four times daily and atropine 1% taken once daily. Supplemental topical steroids were given as needed, and all medications were tapered over the first 4 to 6 weeks after the operation. Patients were examined at 1 day, 1 week, and 1 month postoperatively, and as clinically indicated thereafter. All eyes were included in the analysis, including bilateral cases. A Kaplan–Meier estimate was used to quantify the time to failure after the first treatment. Continuous data were compared using the Student’s t test. Fisher’s exact test was used to compare dichotomous outcome data. A P value of .05 or less was considered statistically significant. RESULTS A total of 124 eyes from 99 patients were included in this review, 67 right eyes and 57 left eyes. 122
Types of preceding glaucoma surgery Goniotomy
45
Trabeculotomy
37
Trabeculectomy
14
Valve
15
The average age of treatment was 2,755 days (standard deviation: 2,103 days). Causes of glaucoma included aphakic glaucoma, pseudophakic glaucoma, congenital glaucoma, Sturge–Weber syndrome, aniridia or other form of anterior segment dysgenesis, phacolytic glaucoma, trauma, retinopathy of prematurity, and uveitic glaucoma (Table 1). TSCP
Initial arc of ciliary process photocoagulation was 262° ± 87° (range: 90° to 360°) of the ciliary body circumference. Fifty-six patients and 72 eyes were treated with TSCP. Fifteen patients received bilateral treatments. Patients’ ages ranged from 0.14 (51 days) to 23.5 years at the time of surgery (mean: 7.63 ± 5.54 years). Table 1 illustrates the primary forms of glaucoma treated using TSCP. Ten eyes (14%) were pseudophakic and 44 eyes (61%) were phakic. Mean follow-up of all eyes was 1,997 ± 1,045 days (5 ± 2.9 years). One eye underwent TSCP to close a cyclodialysis cleft. In this case, success was achieved when IOP increased; therefore, this eye was not included in analysis of the IOPlowering ability of TSCP. Thirty-eight eyes received TSCP as a primary surgical procedure for glaucoma. Thirty-three eyes (46%) had undergone prior glaucoma surgery (range: 1 to 4 glaucoma surgeries) (Table 2). In our series, eyes treated with TSCP received an average of 2.29 ± 2.1 procedures (median: 1.5 procedures). Mean IOP was reduced 28.6% from a baseline of Copyright © SLACK Incorporated
30.4 ± 9.28 mm Hg to a subsequent postoperative IOP of 20.75 ± 9.6 mm Hg. Successful IOP reduction was achieved in 40 eyes (55%) with one session of TSCP. Thirty-two eyes (45%) were classified as treatment failures following first TSCP. Median time to failure of the initial TSCP procedure was 623 ± 620 days (range: 9 to 2,155 days). In 28 of these eyes, treatment failure was secondary to an inadequate decrease of the IOP. All 32 of these eyes underwent a second session of TSCP, and 15 of these eyes demonstrated a favorable response. This brought the cumulative success rate of TSCP to 66.2%. Eight eyes underwent a third consecutive application of TSCP, which was successful. Seven eyes underwent subsequent, non-cyclodestructive glaucoma procedures. Subsequent efforts at IOP control in these 7 eyes often included numerous surgical interventions, such as trabeculectomy with mitomycin C (n = 9), tube-shunt implantation (n = 6), goniotomy (n = 2), and cyclocryotherapy (n = 1). Six of the eyes treated with one session of TSCP and deemed a “treatment success” eventually required an IOP-lowering intervention, reducing the success rate to 57.7%. All eyes underwent cumulative ablations of ciliary processes of 360° or greater; none developed hypotony. None of the phakic eyes developed cataractous changes during the postoperative period. ECP
Initial arc of ciliary process photocoagulation was 220° ± 67° (range: 90° to 360°) of the ciliary body circumference. Forty-three patients and 52 eyes were treated with ECP. Nine patients received bilateral treatments. Patients’ ages ranged from 0.03 (11 days) to 24.4 years at the time of surgery (mean: 7.82 ± 6.05 years). Table 1 illustrates the primary forms of glaucoma treated using ECP. Fifteen eyes (29%) were aphakic, 12 eyes (23%) were pseudophakic, and 15 eyes (54%) were phakic. Mean follow-up of all eyes was 1,995 ± 1,255 days (5 ± 3.4 years). Eleven eyes received ECP as a primary surgical procedure for glaucoma; 13 eyes had undergone prior cyclodestructive procedures with either cryotherapy or externally applied transscleral diode laser. Twentyeight eyes had undergone prior glaucoma surgery (range: 1 to 4 glaucoma surgeries) (Table 2). In our series, eyes treated with ECP received an average
of 1.42 ± 0.72 endolaser procedures (median = 1), 0.92 ± 1.79 TSCP procedures (median = 0), and 2.32 ± 2.17 cyclodestructive procedures following first ECP session (median = 2). All 52 eyes in this series underwent a total average of 3.24 ± 2.52 cyclodestructive procedures (median = 2.5). Mean IOP was reduced 33.2% from a baseline of 33.06 ± 7.91 mm Hg to a subsequent postoperative IOP of 21.3 ± 9.39 mm Hg. Successful IOP reduction was achieved in 24 eyes (46%) with one session of ECP. Twenty-six eyes (54%) were classified as treatment failures following first ECP. Median time to failure of the initial ECP procedure was 373 ± 417 days (range: 17 to 1,239 days). In 21 of these eyes, treatment failure was secondary to an inadequate decrease of the IOP. Repeat ECP was performed on 13 eyes and 6 of these eyes demonstrated a favorable response, increasing the cumulative success rate to 60%. One eye underwent a third consecutive application of endocyclophotocoagulation, which was successful. Final cumulative success rate remained 62% after an average of 1.26 ± 0.51 procedures. Among the 13 eyes not undergoing immediate re-treatment with ECP, 100% underwent treatment with TSCP as the next step. Subsequent efforts at IOP control included various other treatment modalities, including the following: trabeculectomy with mitomycin C (n = 5), tube-shunt implantation (n = 6), trabeculotomy (n = 1), and trabectome (n = 1). Patients appeared to be comfortable after the procedure with only a moderate degree of photophobia and inflammation. No fibrinous reactions, hyphemas, wound leaks, or shallow chambers occurred. Eleven eyes underwent cumulative ablations of 360° of ciliary processes; none developed hypotony. None of the 25 phakic eyes developed cataractous changes during the postoperative period. Treatment Successes Versus Failures
Successfully and unsuccessfully treated eyes showed similar epidemiologic characteristics following cyclophotocoagulation. The baseline age at initial procedure was statistically similar in the two groups. A total of 57 eyes (46%) were considered treatment successes following one or more cyclophotocoagulation treatments. Treatment success was defined as IOP less than 21 mm Hg at the most recent follow-up appointment. Nineteen of these 57 eyes
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mm Hg at follow-up. Twenty-nine eyes did lose vision over the course of follow-up. This was a cohort largely comprising eyes with poor initial visual acuity that went on to develop slight worsening over an average follow-up of 5 years. However, 5 eyes did progress to no light perception. These eyes represent a failed corneal graft, a retinal detachment, and 3 cases of complications following subsequent valve surgery. Cyclophotocoagulation as Primary Surgical Procedure
Figure 1. Kaplan–Meier survival estimate showing duration of successful lowering of intraocular pressure in eyes treated with transscleral cyclophotocoagulation (TSCP) versus endoscopic cyclophotocoagulation (ECP).
were successfully managed without IOP-lowering medications: 15 with TSCP and 4 with ECP. Forty eyes with TSCP and 17 eyes with ECP did not require subsequent surgery. No significant difference was observed between the percentages of successful treatments in those eyes treated initially with TSCP compared to those treated with ECP. A significant difference in initial IOP between the treatment success and treatment failures was observed (pre-intervention IOP: 33.4 versus 26.9 mm Hg, P = .003). Successfully treated eyes had a higher initial IOP. No significant differences were found in the IOP at last follow-up (20.5 vs 18.8, P = .60) and the final number of glaucoma medications required (1.44 vs 1.42). Patient lens status did not appear to have a significant impact on the effectiveness or survival of the procedure. Kaplan–Meier survival estimate failed to show a significant difference between duration of successful IOP-lowering in eyes treated with TSCP versus ECP (Figure 1). Duration of follow-up was equivalent in the two groups. In eyes with baseline visual acuity better than 20/80 (25 eyes), 4 patients lost best-corrected visual acuity (Table 3). Two of these patients lost less than one line of best-corrected visual acuity. One suffered from vision loss unrelated to glaucoma. The other went on to have multiple IOP-lowering procedures and glaucoma was never successfully controlled. Twenty-one of 26 eyes achieved IOP less than 21 124
Forty-nine eyes underwent a cyclodestructive procedure as the initial surgical procedure for IOP control. Thirty-eight eyes had TSCP as a first-line therapy and 11 eyes had ECP. Of the eyes treated initially with TSCP, 21 of 38 did not require additional cyclodestructive treatment (55%) and were considered treatment successes. The remaining 17 underwent re-treatment and IOP was successfully controlled following the second TSCP in 10, bringing the success rate to 79%. ECP as first-line therapy definitively lowered IOP in 6 patients (55%). The remaining 5 patients went on to require noncyclodestructive surgical management. An average decrease of 28.4% in IOP was seen following one TSCP treatment; ECP lowered IOP an average of 43.2% with one procedure. DISCUSSION Management of pediatric glaucoma presents multiple challenges for all members of a child’s caretaking team. Topical therapies can be challenging for the parents to administer and are less effective than in adults. The pediatric ophthalmologist must often turn to surgery to control IOP and halt disease progression. For example, primary congenital glaucoma is successfully managed surgically. Medications are used to temporarily control IOP and clear the cornea in preparation for surgery. Initial surgical treatments include goniotomy, trabeculotomy, or trabeculectomy. Ten percent to 50% percent of patients with primary congenital glaucoma fail goniotomy surgery and require further surgical intervention.9,10 In addition, most patients with glaucoma are aphakic or pseudophakic. These patients and those with glaucoma associated with systemic or ocular anomalies do not respond to goniotomy.11 Therefore, trabeculectomy and valve placement, surgical techniques Copyright © SLACK Incorporated
TABLE 3
Outcomes for Patients With Preoperative BCVA > 20/80 Patient
Preop BCVA
Preop IOP (mm Hg)
Postop BCVA
Postop IOP (mm Hg)
1
20/50
25
20/40
21
2
20/40
17
20/40
18
3
20/80
34
20/100
21
4
20/20
15
20/20
14
5
20/25
27
20/25
19
6
20/30
30
20/125
15
7
20/40
27
20/25
16
8
20/70
23
20/20
17
9
20/20
19
20/20
18
10
+
20/50
27
20/25
12
11
20//80
17
20/80
19
12
20/40
26
20/25+2
27
13
20/25
25
20/25
19
14
20/25
25
20/40
20
15
20/25
30
20/25
9
16
20/40
26
20/25
21
-2
-2
-2
17
20/80
46
20/60
23
18
20/60
26
20/125
21
19
20/60
31
20/70
21
20
20/25
26
20/30
14
21
20/25-2
18
20/25
22
22
20/80
29
20/70
7
23
20/80
34
8/500
25
24
-2
20/40
30
25
20/60+
26
20/50
+2
20/60
26 21
BVCA = best-corrected visual acuity; preop = preoperative; postop = postoperative; IOP = intraocular pressure
traditionally used in adult glaucoma, are often the next step in these complicated patients. However, despite high success rates in adult patients, these procedures are fraught with problems in the pediatric population. The success or failure of filtering surgery depends on the postoperative management. This is more complicated in children, where laser suture lysis, releasing sutures, and injecting anti-metabolites require general anesthesia. Because of this and a child’s more robust scarring response, pediatric trabeculectomies have a failure rate much higher than in adults.12 Furthermore, even with a successful operation, the child faces a lifetime risk for blebitis and endophthalmitis.3,12,13 In children with neurologic or behavioral impair-
ments, who cannot verbalize changes in vision or pain, this is of particular concern. Our case series includes one patient who developed endophthalmitis and phthisis following valve surgery. Cyclodestructive surgery was introduced during the early 1930s. Beginning in the 1950s, cyclocryotherapy was being used to damage the ciliary epithelium and decrease aqueous flow.14,15 Cryotherapy fell out of favor when its complication rates were shown to be unacceptably high. Shields reviewed 114 adult and pediatric cases and found that 60% of eyes had a worse visual acuity after treatment than before treatment and 12% of eyes developed phthisis.14 TSCP became the treatment of choice for cyclodestructive procedures in pediatric patients in 1995.16 However,
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transscleral laser treatment shares an essential shortcoming with cryotherapy: the surgeon is unable to visualize treatment effect at the time of surgery. ECP solves this problem by allowing direct visualization and treatment of the ciliary processes. Neely and Plager reported success in their series of 36 eyes treated with ECP for pediatric glaucoma.17 Their series included a comparison of the safety and efficacy of ECP in their patients with other reports of cyclodestructive procedures in the pediatric population. Although no significant difference in efficacy was reported, the theoretical advantage of visualized destruction of the ciliary body was substantiated by the relatively fewer re-treatments. Reports of ECP after unsuccessful TSCP have revealed numerous misplaced laser burns in the pars plana region on endoscopic visualization of the ciliary body.18 With this evidence, we sought to compile the first published comparison of the safety and efficacy of TSCP compared to ECP. We found in our series a 33.2% and 28.6% reduction in IOP with ECP and TSCP, respectively. Eyes treated with ECP underwent an average of 3.24 cyclodestructive procedures; eyes treated with TSCP underwent 2.29 cyclodestructive treatments on average. These differences were not statistically significant. A final cumulative success rate of 67.6% after an average of 1.29 ± 2.1 procedures and a cumulative arc of treatment averaging 1,000° ± 626° of ciliary processes was seen with TSCP. Similarly, 62% of eyes treated with ECP were considered treatment successes after an average of 1.26 ± 0.51 procedures and a cumulative arc of treatment averaging 289° ± 115° of ciliary processes. Consequently, twothirds of our patients were able to avoid penetrating surgery and the associated risks after one or more cyclodestructive procedures. Equal percentages of eyes in each group were able to maintain IOP of 21 mm Hg or less after just one treatment. A Kaplan–Meier curve showed equivalent survival trends between eyes treated with ECP and those treated with TSCP (P = .56). Although this result is interesting, our study is retrospective and eyes were therefore not randomized to treatment. Selection bias may have influenced the choice of TSCP versus ECP. Certain forms of glaucoma (aphakic and pseudophakic) may respond better to ECP.19 The surgeons made treatment decisions on a case-by-case basis, without formal treatment or re-treatment algorithms. 126
IOP success was defined as IOP at last followup, rather than sustained IOP lowering over a set time period. For these reasons, further investigation would be necessary to statistically validate our observations. Safety analysis showed that most children with good preoperative vision maintained their bestcorrected visual acuities. The major adverse effect as reported by patient or parent was transient photophobia, likely due to transient uveitis. However, objective evidence of postoperative uveitis may have escaped detection because it is more difficult to detect with portable slit-lamp examination. The uveitis did not persist, because uveitis was not present at examinations under anesthesia performed months after laser treatment. Our study is susceptible to selection bias because the patients were not randomized to TSCP versus ECP. However, no specific identifiable confounding variable can be identified that predisposed a surgeon to choose one treatment over another. We must assume that each child received what was considered the surgical option with the best chance of success. Therefore, our results may be considered biased toward the best possible chance of success for each individual treatment. We conclude that TSCP and ECP are relatively safe and effective treatments for pediatric glaucomas. It is not necessary to reserve these treatments for use only in patients with end-stage disease and poor vision. Our results support the conclusion that TSCP and ECP may be used safely as first-line therapy to achieve control of IOP in all forms of pediatric glaucoma. The efficacy of these two treatments was comparable. REFERENCES
1. Barsoum-Homsy M, Chevrette L. Incidence and prognosis of childhood glaucoma: a study of 63 cases. Ophthalmology. 1986;93:1323-1327. 2. Papadopoulos M, Khaw PT. Childhood glaucoma. In: Taylor D, Hoyt CS, eds. Pediatric Ophthalmology and Strabismus, 3rd ed. Philadelphia: Elsevier Saunders; 2005:458-471. 3. Sidoti PA, Belmonte SJ, Liebmann JM, Ritch R. Trabeculectomy with mitomycin-C in the treatment of pediatric glaucomas. Ophthalmology. 2000;107:422-429. 4. Pastor SA, Singh K, Lee DA, et al. Cyclophotocoagulation: a report by the American Academy of Ophthalmology. Ophthalmology. 2001;108:2130-2138. 5. Beckman H, Kinoshita A, Rota AN, Sugar HS. Transscleral ruby laser irradiation of the ciliary body in the treatment of intractable glaucoma. Trans Am Acad Ophthalmol Otolaryngol. 1972;76:423436. 6. Beckman H, Sugar HS. Neodymium laser cyclocoagulation. Arch Ophthalmol. 1973;90:27-28. 7. Hampton C, Shields MB, Miller KN, Blasini M. Evaluation of a
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protocol for transscleral neodymium:YAG cyclophotocoagulation in one hundred patients. Ophthalmology. 1990;97:910-917. Plager DA, Neely DE. Intermediate-term results of endoscopic diode laser cyclophotocoagulation for pediatric glaucoma. J AAPOS. 1999;3:131-137. Ishida K, Mandal AK, Netland PA. Glaucoma drainage implants in pediatric patients. Ophthalmol Clin North Am. 2005;18:431442. Taylor RH, Ainsworth JR, Evans AR, Levin AV. The epidemiology of pediatric glaucoma: the Toronto experience. J AAPOS. 1999;3:308-315. Wallace DK, Plager DA, Synder SK, Raisedana A, Helveston EM, Ellis FD. Surgical results of secondary glaucomas in childhood. Ophthalmology. 1998;105:101-111. Beck AD, Wilson WR, Lynch MG, Lynn MJ, Noe R. Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma. Am J Ophthalmol. 1998;126:648-657. Wells AP, Cordeiro MF, Bunce C, Khaw PT. Cystic bleb formation and related complications in limbus- versus fornix-based con-
14. 15. 16. 17. 18. 19.
junctival flaps in pediatric and young adult trabeculectomy with mitomycin C. Ophthalmology. 2003;110:2192-2197. Shields MB. Cyclodestructive surgery for glaucoma: past, present, and future. Trans Am Ophthalmol Soc. 1985;83:285-303. Benson MT, Nelson ME. Cyclocryotherapy: a review of cases over a 10-year period. Br J Ophthalmol. 1990;74:103-105. Phelan MJ, Higginbotham EJ. Contact transscleral Nd:YAG laser cyclophotocoagulation for the treatment of refractory pediatric glaucoma. Ophthalmic Surg Lasers. 1995;26:401-403. Neely DE, Plager DA. Endocyclophotocoagulation for management of difficult pediatric glaucomas. J AAPOS. 2001;5:221-229. Barkana Y, Morad Y, Ben-nun J. Endoscopic photocoagulation of the ciliary body after repeated failure of trans-scleral diode-laser cyclophotocoagulation. Am J Ophthalmol. 2002;133:405-407. 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;11:34-44.
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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
ABSTRACT Purpose: Among the options for surgical management of pediatric glaucoma, destruction of the ciliary body reduces aqueous production and, consequently, intraocular pressure (IOP). Compared to more invasive filtering and shunt procedures, cyclodestruction is an attractive option for control of IOP in pediatric glaucomas. Methods: The relative reduction in IOP, duration of effect, and comparable safety and efficacy of transscleral cyclophotocoagulation (TSCP) and endoscopic cyclophotocoagulation (ECP) in pediatric patients with glaucoma was studied in this retrospective chart review.
erage of 2.29 cyclodestructive treatments. These differences were not statistically significant. A final success rate of 67.6% after TSCP and 62% after ECP failed to significantly differ between the two groups. Consequently, two-thirds of the patients were able to avoid penetrating surgery and the associated risks after one or more cyclodestructive procedures. Conclusions: TSCP and ECP are safe, effective, and comparable treatments for pediatric glaucomas. The results suggest that TSCP and ECP may be considered first-line therapy to achieve control of IOP in all forms of pediatric glaucoma.
Results: A reduction in IOP of 28.6% and 33.2% with TSCP and ECP, respectively, was found. Eyes treated with ECP underwent an average of 3.24 cyclodestructive procedures; eyes treated with TSCP underwent an av-
[J Pediatr Ophthalmol Strabismus 2014;51(2):120127.]
INTRODUCTION Pediatric glaucoma accounts for up to 10% of all cases of blindness in children.1 The pediatric glaucomas are a heterogeneous group, including both primary and secondary causes. Primary congenital glaucoma occurs within the first few years of life, represents the most common cause of glaucoma in childhood, and is caused by abnormal development of the anterior chamber angle and subsequent
impaired aqueous outflow. In secondary glaucoma, aqueous outflow is reduced due to either a congenital or an acquired ocular disease or systemic disorder, including inflammatory, neoplastic, hamartomatous, metabolic, or congenital abnormalities.2 Pediatric glaucoma is a challenging disorder to treat, with management being primarily surgical. In contrast to adults, topical medications are traditionally more of a temporizing measure. Given the chal-
From the Department of Ophthalmology and Visual Sciences, Washington University School of Medicine (CLK, LT, GTL, SMC); and the St. Louis Children’s Hospital, St. Louis, Missouri (LT, GTL, SMC). Submitted: September 16, 2013; Accepted: November 19, 2013; Posted online: February 18, 2014 The authors have no financial or proprietary interest in the materials presented herein. Correspondence: Courtney L. Kraus, MD, 660 S. Euclid Ave., St. Louis, MO 63110. E-mail: [email protected] doi: 10.3928/01913913-20140211-01
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lenge of instilling drops in this age group, their limited efficacy, frequent dosing, and restrictions on use of certain medications (ie, brimonidine), attempts to treat exclusively with drops are generally unsuccessful. Additionally, traditional surgical interventions used in adult patients with glaucoma (laser trabeculoplasty and trabeculectomy) have their own limitations. Laser trabeculotomy is impossible in an uncooperative child, whereas trabeculectomy has risks such as late bleb-related infection, hypotony, and phthisis.3 Destruction of the ciliary body serves to reduce aqueous secretion and, consequently, intraocular pressure (IOP). A variety of cyclodestructive procedures have been used to reduce aqueous production, including cyclocryotherapy and Nd:YAG, argon, and diode thermal lasers.4 Historically, cyclodestructive procedures have been reserved for adult patients who have elevated IOP and failed trabeculectomy or tube shunts, limited visual potential, or painful eyes. Because these techniques are less invasive than filtering surgery, minimizing both immediate postoperative complications and lifetime risk of blebitis/endophthalmitis, their use in children is particularly attractive. Beckman et al.5 and Beckman and Sugar6 first described the use of transscleral cyclophotocoagulation (TSCP). It is a noninvasive cyclodestructive technique where transscleral application of infrared light is absorbed by the pigmented epithelial cells of the ciliary body, causing destruction of ciliary body epithelium and coagulation necrosis of ciliary body.7 In contrast, endoscopic cyclophotocoagulation (ECP) allows direct visualization of the ciliary processes and precise treatment using a diode laser emitting infrared light. Using a lower energy and more accurately targeting the tissue than transscleral procedures, ECP may increase the success of cycloablation while decreasing complications such as visual loss and phthisis.8 The safety and efficacy of TSCP and ECP have been studied in the pediatric population and both have reportedly been successful at lowering IOP. However, the relative reduction, duration of effect, and comparable safety and efficacy of each technique has not been performed. The purpose of this study was to compare the efficacy of TSCP and ECP in controlling IOP in pediatric patients with glaucoma. PATIENTS AND METHODS A retrospective analysis was conducted of the outcomes of eyes being treated for glaucoma using
cyclophotocoagulation by three surgeons (LT, GTL, SMC). The Institutional Review Board of the Human Research Protection Office of Washington University, St. Louis approved this study. All patients were younger than 18 years and undergoing either TSCP or ECP for treatment of glaucoma at St. Louis Children’s Hospital from 1995 to 2007. Causes of glaucoma included aphakia, pseudophakia, aniridia or anterior segment dysgenesis, Sturge–Weber disease, uveitis, trauma, retinopathy of prematurity (ROP), and congenital glaucoma. Measurable outcomes such as reduction in IOP, avoidance of additional glaucoma procedures, ability to discontinue drop therapy, and better control with synergistic pharmaceutical therapy were examined. Additionally, safety and frequency of adverse outcomes following the two procedures were analyzed. Comparison of efficacy was of particular interest and was assessed using the number of subsequent cyclodestructive events per eye, time to next surgery (cyclodestructive, tube shunt, or filter), and mean IOP reduction. The initial and follow-up treatments of a child’s glaucoma were determined on a case-by-case basis. Decisions to add medication or perform surgery were made by the individual surgeon and based on persistently elevated IOP, optic nerve change, or observed myopic shift. Surgical management was pursued according to what procedure was believed to be in the best interest of the child and could include cyclophotocoagulation, tube shunt, or filtering. Whether a patient underwent TSCP or ECP was left to the discretion of the individual surgeon. Patient data collected from the preoperative and postoperative visits included IOP, visual acuity, and the number of glaucoma medications required. Prior glaucoma procedures such as goniotomy, trabeculotomy, trabeculectomy, and tube shunts were recorded. The choice of cyclodestructive procedure was at the surgeon’s discretion. Several eyes underwent multiple cyclodestructive treatments. For TSCP treatments, power ranged from 1,500 to 2,000 mW with a duration time of 2,000 ms, treating 90° to 360°. The probe was placed at the limbus with adjustment of treatment parameters based on the occurrence of “pops” (adjusted down on power for consecutive “pops”). For ECP treatments, an operating microscope was employed and a limbal incision was created. In phakic patients, special care was taken to avoid the anterior lens capsule. The ophthalmic laser microendoscope was
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TABLE 1
TABLE 2
Categories of Glaucoma and No. Undergoing ECP and TSCP as First Cyclodestructive Procedure for IOP Control
Treatment Preceding Cyclophotocoagulation Variable
Category
ECP
TSCP
No. of preceding surgeries
Aphakic
12 (23%)
18 (25%)
0
63
Pseudophakic
12 (23%)
10 (14%)
1
27
Congenital
No. of Patients
11 (22%)
21 (29%)
2
15
Anterior segment dysgenesis
4 (8%)
5 (7%)
3
10
Aniridia
5 (9%)
1 (1%)
4
7
Sturge–Weber
5 (9%)
5 (7%)
Trauma
2 (4%)
5 (7%)
Retinopathy of prematurity
1 (1%)
3 (5%)
Uveitis
1 (1%)
1 (1%)
Other
1 (1%)
2 (2%)
Total
52
72
ECP = endoscopic cyclophotocoagulation; TSCP = transscleral cyclophotocoagulation; IOP = intraocular pressure
then inserted into the anterior chamber and directed through the pupil to access the ciliary body and ciliary processes. Using fiberoptic video images, individual ciliary processes were identifiable for photocoagulation. One or two pulses of 400 to 800 mW were applied for 1 to 2 seconds until visible whitening and contracture of the ciliary process occurred; 90° to 360° of contiguous ciliary processes were treated in this manner. Postoperative medications included an antibiotic-steroid preparation taken four times daily and atropine 1% taken once daily. Supplemental topical steroids were given as needed, and all medications were tapered over the first 4 to 6 weeks after the operation. Patients were examined at 1 day, 1 week, and 1 month postoperatively, and as clinically indicated thereafter. All eyes were included in the analysis, including bilateral cases. A Kaplan–Meier estimate was used to quantify the time to failure after the first treatment. Continuous data were compared using the Student’s t test. Fisher’s exact test was used to compare dichotomous outcome data. A P value of .05 or less was considered statistically significant. RESULTS A total of 124 eyes from 99 patients were included in this review, 67 right eyes and 57 left eyes. 122
Types of preceding glaucoma surgery Goniotomy
45
Trabeculotomy
37
Trabeculectomy
14
Valve
15
The average age of treatment was 2,755 days (standard deviation: 2,103 days). Causes of glaucoma included aphakic glaucoma, pseudophakic glaucoma, congenital glaucoma, Sturge–Weber syndrome, aniridia or other form of anterior segment dysgenesis, phacolytic glaucoma, trauma, retinopathy of prematurity, and uveitic glaucoma (Table 1). TSCP
Initial arc of ciliary process photocoagulation was 262° ± 87° (range: 90° to 360°) of the ciliary body circumference. Fifty-six patients and 72 eyes were treated with TSCP. Fifteen patients received bilateral treatments. Patients’ ages ranged from 0.14 (51 days) to 23.5 years at the time of surgery (mean: 7.63 ± 5.54 years). Table 1 illustrates the primary forms of glaucoma treated using TSCP. Ten eyes (14%) were pseudophakic and 44 eyes (61%) were phakic. Mean follow-up of all eyes was 1,997 ± 1,045 days (5 ± 2.9 years). One eye underwent TSCP to close a cyclodialysis cleft. In this case, success was achieved when IOP increased; therefore, this eye was not included in analysis of the IOPlowering ability of TSCP. Thirty-eight eyes received TSCP as a primary surgical procedure for glaucoma. Thirty-three eyes (46%) had undergone prior glaucoma surgery (range: 1 to 4 glaucoma surgeries) (Table 2). In our series, eyes treated with TSCP received an average of 2.29 ± 2.1 procedures (median: 1.5 procedures). Mean IOP was reduced 28.6% from a baseline of Copyright © SLACK Incorporated
30.4 ± 9.28 mm Hg to a subsequent postoperative IOP of 20.75 ± 9.6 mm Hg. Successful IOP reduction was achieved in 40 eyes (55%) with one session of TSCP. Thirty-two eyes (45%) were classified as treatment failures following first TSCP. Median time to failure of the initial TSCP procedure was 623 ± 620 days (range: 9 to 2,155 days). In 28 of these eyes, treatment failure was secondary to an inadequate decrease of the IOP. All 32 of these eyes underwent a second session of TSCP, and 15 of these eyes demonstrated a favorable response. This brought the cumulative success rate of TSCP to 66.2%. Eight eyes underwent a third consecutive application of TSCP, which was successful. Seven eyes underwent subsequent, non-cyclodestructive glaucoma procedures. Subsequent efforts at IOP control in these 7 eyes often included numerous surgical interventions, such as trabeculectomy with mitomycin C (n = 9), tube-shunt implantation (n = 6), goniotomy (n = 2), and cyclocryotherapy (n = 1). Six of the eyes treated with one session of TSCP and deemed a “treatment success” eventually required an IOP-lowering intervention, reducing the success rate to 57.7%. All eyes underwent cumulative ablations of ciliary processes of 360° or greater; none developed hypotony. None of the phakic eyes developed cataractous changes during the postoperative period. ECP
Initial arc of ciliary process photocoagulation was 220° ± 67° (range: 90° to 360°) of the ciliary body circumference. Forty-three patients and 52 eyes were treated with ECP. Nine patients received bilateral treatments. Patients’ ages ranged from 0.03 (11 days) to 24.4 years at the time of surgery (mean: 7.82 ± 6.05 years). Table 1 illustrates the primary forms of glaucoma treated using ECP. Fifteen eyes (29%) were aphakic, 12 eyes (23%) were pseudophakic, and 15 eyes (54%) were phakic. Mean follow-up of all eyes was 1,995 ± 1,255 days (5 ± 3.4 years). Eleven eyes received ECP as a primary surgical procedure for glaucoma; 13 eyes had undergone prior cyclodestructive procedures with either cryotherapy or externally applied transscleral diode laser. Twentyeight eyes had undergone prior glaucoma surgery (range: 1 to 4 glaucoma surgeries) (Table 2). In our series, eyes treated with ECP received an average
of 1.42 ± 0.72 endolaser procedures (median = 1), 0.92 ± 1.79 TSCP procedures (median = 0), and 2.32 ± 2.17 cyclodestructive procedures following first ECP session (median = 2). All 52 eyes in this series underwent a total average of 3.24 ± 2.52 cyclodestructive procedures (median = 2.5). Mean IOP was reduced 33.2% from a baseline of 33.06 ± 7.91 mm Hg to a subsequent postoperative IOP of 21.3 ± 9.39 mm Hg. Successful IOP reduction was achieved in 24 eyes (46%) with one session of ECP. Twenty-six eyes (54%) were classified as treatment failures following first ECP. Median time to failure of the initial ECP procedure was 373 ± 417 days (range: 17 to 1,239 days). In 21 of these eyes, treatment failure was secondary to an inadequate decrease of the IOP. Repeat ECP was performed on 13 eyes and 6 of these eyes demonstrated a favorable response, increasing the cumulative success rate to 60%. One eye underwent a third consecutive application of endocyclophotocoagulation, which was successful. Final cumulative success rate remained 62% after an average of 1.26 ± 0.51 procedures. Among the 13 eyes not undergoing immediate re-treatment with ECP, 100% underwent treatment with TSCP as the next step. Subsequent efforts at IOP control included various other treatment modalities, including the following: trabeculectomy with mitomycin C (n = 5), tube-shunt implantation (n = 6), trabeculotomy (n = 1), and trabectome (n = 1). Patients appeared to be comfortable after the procedure with only a moderate degree of photophobia and inflammation. No fibrinous reactions, hyphemas, wound leaks, or shallow chambers occurred. Eleven eyes underwent cumulative ablations of 360° of ciliary processes; none developed hypotony. None of the 25 phakic eyes developed cataractous changes during the postoperative period. Treatment Successes Versus Failures
Successfully and unsuccessfully treated eyes showed similar epidemiologic characteristics following cyclophotocoagulation. The baseline age at initial procedure was statistically similar in the two groups. A total of 57 eyes (46%) were considered treatment successes following one or more cyclophotocoagulation treatments. Treatment success was defined as IOP less than 21 mm Hg at the most recent follow-up appointment. Nineteen of these 57 eyes
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123
mm Hg at follow-up. Twenty-nine eyes did lose vision over the course of follow-up. This was a cohort largely comprising eyes with poor initial visual acuity that went on to develop slight worsening over an average follow-up of 5 years. However, 5 eyes did progress to no light perception. These eyes represent a failed corneal graft, a retinal detachment, and 3 cases of complications following subsequent valve surgery. Cyclophotocoagulation as Primary Surgical Procedure
Figure 1. Kaplan–Meier survival estimate showing duration of successful lowering of intraocular pressure in eyes treated with transscleral cyclophotocoagulation (TSCP) versus endoscopic cyclophotocoagulation (ECP).
were successfully managed without IOP-lowering medications: 15 with TSCP and 4 with ECP. Forty eyes with TSCP and 17 eyes with ECP did not require subsequent surgery. No significant difference was observed between the percentages of successful treatments in those eyes treated initially with TSCP compared to those treated with ECP. A significant difference in initial IOP between the treatment success and treatment failures was observed (pre-intervention IOP: 33.4 versus 26.9 mm Hg, P = .003). Successfully treated eyes had a higher initial IOP. No significant differences were found in the IOP at last follow-up (20.5 vs 18.8, P = .60) and the final number of glaucoma medications required (1.44 vs 1.42). Patient lens status did not appear to have a significant impact on the effectiveness or survival of the procedure. Kaplan–Meier survival estimate failed to show a significant difference between duration of successful IOP-lowering in eyes treated with TSCP versus ECP (Figure 1). Duration of follow-up was equivalent in the two groups. In eyes with baseline visual acuity better than 20/80 (25 eyes), 4 patients lost best-corrected visual acuity (Table 3). Two of these patients lost less than one line of best-corrected visual acuity. One suffered from vision loss unrelated to glaucoma. The other went on to have multiple IOP-lowering procedures and glaucoma was never successfully controlled. Twenty-one of 26 eyes achieved IOP less than 21 124
Forty-nine eyes underwent a cyclodestructive procedure as the initial surgical procedure for IOP control. Thirty-eight eyes had TSCP as a first-line therapy and 11 eyes had ECP. Of the eyes treated initially with TSCP, 21 of 38 did not require additional cyclodestructive treatment (55%) and were considered treatment successes. The remaining 17 underwent re-treatment and IOP was successfully controlled following the second TSCP in 10, bringing the success rate to 79%. ECP as first-line therapy definitively lowered IOP in 6 patients (55%). The remaining 5 patients went on to require noncyclodestructive surgical management. An average decrease of 28.4% in IOP was seen following one TSCP treatment; ECP lowered IOP an average of 43.2% with one procedure. DISCUSSION Management of pediatric glaucoma presents multiple challenges for all members of a child’s caretaking team. Topical therapies can be challenging for the parents to administer and are less effective than in adults. The pediatric ophthalmologist must often turn to surgery to control IOP and halt disease progression. For example, primary congenital glaucoma is successfully managed surgically. Medications are used to temporarily control IOP and clear the cornea in preparation for surgery. Initial surgical treatments include goniotomy, trabeculotomy, or trabeculectomy. Ten percent to 50% percent of patients with primary congenital glaucoma fail goniotomy surgery and require further surgical intervention.9,10 In addition, most patients with glaucoma are aphakic or pseudophakic. These patients and those with glaucoma associated with systemic or ocular anomalies do not respond to goniotomy.11 Therefore, trabeculectomy and valve placement, surgical techniques Copyright © SLACK Incorporated
TABLE 3
Outcomes for Patients With Preoperative BCVA > 20/80 Patient
Preop BCVA
Preop IOP (mm Hg)
Postop BCVA
Postop IOP (mm Hg)
1
20/50
25
20/40
21
2
20/40
17
20/40
18
3
20/80
34
20/100
21
4
20/20
15
20/20
14
5
20/25
27
20/25
19
6
20/30
30
20/125
15
7
20/40
27
20/25
16
8
20/70
23
20/20
17
9
20/20
19
20/20
18
10
+
20/50
27
20/25
12
11
20//80
17
20/80
19
12
20/40
26
20/25+2
27
13
20/25
25
20/25
19
14
20/25
25
20/40
20
15
20/25
30
20/25
9
16
20/40
26
20/25
21
-2
-2
-2
17
20/80
46
20/60
23
18
20/60
26
20/125
21
19
20/60
31
20/70
21
20
20/25
26
20/30
14
21
20/25-2
18
20/25
22
22
20/80
29
20/70
7
23
20/80
34
8/500
25
24
-2
20/40
30
25
20/60+
26
20/50
+2
20/60
26 21
BVCA = best-corrected visual acuity; preop = preoperative; postop = postoperative; IOP = intraocular pressure
traditionally used in adult glaucoma, are often the next step in these complicated patients. However, despite high success rates in adult patients, these procedures are fraught with problems in the pediatric population. The success or failure of filtering surgery depends on the postoperative management. This is more complicated in children, where laser suture lysis, releasing sutures, and injecting anti-metabolites require general anesthesia. Because of this and a child’s more robust scarring response, pediatric trabeculectomies have a failure rate much higher than in adults.12 Furthermore, even with a successful operation, the child faces a lifetime risk for blebitis and endophthalmitis.3,12,13 In children with neurologic or behavioral impair-
ments, who cannot verbalize changes in vision or pain, this is of particular concern. Our case series includes one patient who developed endophthalmitis and phthisis following valve surgery. Cyclodestructive surgery was introduced during the early 1930s. Beginning in the 1950s, cyclocryotherapy was being used to damage the ciliary epithelium and decrease aqueous flow.14,15 Cryotherapy fell out of favor when its complication rates were shown to be unacceptably high. Shields reviewed 114 adult and pediatric cases and found that 60% of eyes had a worse visual acuity after treatment than before treatment and 12% of eyes developed phthisis.14 TSCP became the treatment of choice for cyclodestructive procedures in pediatric patients in 1995.16 However,
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transscleral laser treatment shares an essential shortcoming with cryotherapy: the surgeon is unable to visualize treatment effect at the time of surgery. ECP solves this problem by allowing direct visualization and treatment of the ciliary processes. Neely and Plager reported success in their series of 36 eyes treated with ECP for pediatric glaucoma.17 Their series included a comparison of the safety and efficacy of ECP in their patients with other reports of cyclodestructive procedures in the pediatric population. Although no significant difference in efficacy was reported, the theoretical advantage of visualized destruction of the ciliary body was substantiated by the relatively fewer re-treatments. Reports of ECP after unsuccessful TSCP have revealed numerous misplaced laser burns in the pars plana region on endoscopic visualization of the ciliary body.18 With this evidence, we sought to compile the first published comparison of the safety and efficacy of TSCP compared to ECP. We found in our series a 33.2% and 28.6% reduction in IOP with ECP and TSCP, respectively. Eyes treated with ECP underwent an average of 3.24 cyclodestructive procedures; eyes treated with TSCP underwent 2.29 cyclodestructive treatments on average. These differences were not statistically significant. A final cumulative success rate of 67.6% after an average of 1.29 ± 2.1 procedures and a cumulative arc of treatment averaging 1,000° ± 626° of ciliary processes was seen with TSCP. Similarly, 62% of eyes treated with ECP were considered treatment successes after an average of 1.26 ± 0.51 procedures and a cumulative arc of treatment averaging 289° ± 115° of ciliary processes. Consequently, twothirds of our patients were able to avoid penetrating surgery and the associated risks after one or more cyclodestructive procedures. Equal percentages of eyes in each group were able to maintain IOP of 21 mm Hg or less after just one treatment. A Kaplan–Meier curve showed equivalent survival trends between eyes treated with ECP and those treated with TSCP (P = .56). Although this result is interesting, our study is retrospective and eyes were therefore not randomized to treatment. Selection bias may have influenced the choice of TSCP versus ECP. Certain forms of glaucoma (aphakic and pseudophakic) may respond better to ECP.19 The surgeons made treatment decisions on a case-by-case basis, without formal treatment or re-treatment algorithms. 126
IOP success was defined as IOP at last followup, rather than sustained IOP lowering over a set time period. For these reasons, further investigation would be necessary to statistically validate our observations. Safety analysis showed that most children with good preoperative vision maintained their bestcorrected visual acuities. The major adverse effect as reported by patient or parent was transient photophobia, likely due to transient uveitis. However, objective evidence of postoperative uveitis may have escaped detection because it is more difficult to detect with portable slit-lamp examination. The uveitis did not persist, because uveitis was not present at examinations under anesthesia performed months after laser treatment. Our study is susceptible to selection bias because the patients were not randomized to TSCP versus ECP. However, no specific identifiable confounding variable can be identified that predisposed a surgeon to choose one treatment over another. We must assume that each child received what was considered the surgical option with the best chance of success. Therefore, our results may be considered biased toward the best possible chance of success for each individual treatment. We conclude that TSCP and ECP are relatively safe and effective treatments for pediatric glaucomas. It is not necessary to reserve these treatments for use only in patients with end-stage disease and poor vision. Our results support the conclusion that TSCP and ECP may be used safely as first-line therapy to achieve control of IOP in all forms of pediatric glaucoma. The efficacy of these two treatments was comparable. REFERENCES
1. Barsoum-Homsy M, Chevrette L. Incidence and prognosis of childhood glaucoma: a study of 63 cases. Ophthalmology. 1986;93:1323-1327. 2. Papadopoulos M, Khaw PT. Childhood glaucoma. In: Taylor D, Hoyt CS, eds. Pediatric Ophthalmology and Strabismus, 3rd ed. Philadelphia: Elsevier Saunders; 2005:458-471. 3. Sidoti PA, Belmonte SJ, Liebmann JM, Ritch R. Trabeculectomy with mitomycin-C in the treatment of pediatric glaucomas. Ophthalmology. 2000;107:422-429. 4. Pastor SA, Singh K, Lee DA, et al. Cyclophotocoagulation: a report by the American Academy of Ophthalmology. Ophthalmology. 2001;108:2130-2138. 5. Beckman H, Kinoshita A, Rota AN, Sugar HS. Transscleral ruby laser irradiation of the ciliary body in the treatment of intractable glaucoma. Trans Am Acad Ophthalmol Otolaryngol. 1972;76:423436. 6. Beckman H, Sugar HS. Neodymium laser cyclocoagulation. Arch Ophthalmol. 1973;90:27-28. 7. Hampton C, Shields MB, Miller KN, Blasini M. Evaluation of a
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protocol for transscleral neodymium:YAG cyclophotocoagulation in one hundred patients. Ophthalmology. 1990;97:910-917. Plager DA, Neely DE. Intermediate-term results of endoscopic diode laser cyclophotocoagulation for pediatric glaucoma. J AAPOS. 1999;3:131-137. Ishida K, Mandal AK, Netland PA. Glaucoma drainage implants in pediatric patients. Ophthalmol Clin North Am. 2005;18:431442. Taylor RH, Ainsworth JR, Evans AR, Levin AV. The epidemiology of pediatric glaucoma: the Toronto experience. J AAPOS. 1999;3:308-315. Wallace DK, Plager DA, Synder SK, Raisedana A, Helveston EM, Ellis FD. Surgical results of secondary glaucomas in childhood. Ophthalmology. 1998;105:101-111. Beck AD, Wilson WR, Lynch MG, Lynn MJ, Noe R. Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma. Am J Ophthalmol. 1998;126:648-657. Wells AP, Cordeiro MF, Bunce C, Khaw PT. Cystic bleb formation and related complications in limbus- versus fornix-based con-
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junctival flaps in pediatric and young adult trabeculectomy with mitomycin C. Ophthalmology. 2003;110:2192-2197. Shields MB. Cyclodestructive surgery for glaucoma: past, present, and future. Trans Am Ophthalmol Soc. 1985;83:285-303. Benson MT, Nelson ME. Cyclocryotherapy: a review of cases over a 10-year period. Br J Ophthalmol. 1990;74:103-105. Phelan MJ, Higginbotham EJ. Contact transscleral Nd:YAG laser cyclophotocoagulation for the treatment of refractory pediatric glaucoma. Ophthalmic Surg Lasers. 1995;26:401-403. Neely DE, Plager DA. Endocyclophotocoagulation for management of difficult pediatric glaucomas. J AAPOS. 2001;5:221-229. Barkana Y, Morad Y, Ben-nun J. Endoscopic photocoagulation of the ciliary body after repeated failure of trans-scleral diode-laser cyclophotocoagulation. Am J Ophthalmol. 2002;133:405-407. 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;11:34-44.
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