Cyclophotocoagulation versus Aqueous Tube Shunt as a Secondary Intervention Following Primary Aqueous Tube Shunt in Treatment of Pediatric Glaucoma

Abstract

Purpose:: This study examined the efficacy of transscleral diode cyclophotocoagulation (CPC) versus a second tube shunt following failure of an initial tube shunt on maximal medical therapy in treatment of refractory childhood glaucoma.

Methods:: Seventeen eyes from fourteen patients with pediatric glaucoma were included in this retrospective study. All patients were 18 years old or less, failed an initial tube shunt and subsequently were treated with either diode CPC or tube shunt for control of intraocular pressure between the years 1999 to 2006. Eight tube shunts were performed using four Ahmed S2 models, one Ahmed B4 model and three Baerveldt 350mm² models. Nine transscleral diode CPC procedures were performed using an OcuLight SLx diode laser (Iris Medical Inc., CA) with an Iris G-probe. Power ranged from 1000-1500mW with a duration time from 3000ms to 4000 ms with an average of 17.4 (range 14 to 22) applications. Primary outcome compared in the two treatment arms was change in IOP. Secondary outcomes included change in visual acuity, number of medications at last follow-up and complications. Success was defined as an IOP ≤ 22 mmHg on medical therapy, no devastating complications and no further glaucoma surgery being performed or recommended.

Results:: Nine eyes had diode CPC and eight eyes had a tube shunt as a secondary procedure with an average follow-up of 32.1 months and 36.4 months, respectively. The average IOP in the CPC group before surgery was 31.6 +/- 5.10mmHg and 18.4 +/- 5.36mmHg after the procedure. The number of medications also decreased from 3.44 to 3.0. Average IOP in the tube shunt group was 32.2 +/- 7.0 mmHg prior and 16.9 +/- 5.67mmHg following surgical intervention. Number of medications increased from 2.88 to 3.29 in this group. Visual acuity was improved or unchanged in 77.8% of patients in the diode CPC group and 62.5% of the tube shunt group. A successful outcome was found in 66.7% and 75% of the patients in the CPC group and tube shunt group, respectively. Complications included one case of phthisis in the CPC treatment arm and one case each of retinal detachment and suprachoroidal hemorrhage in the tube shunt treatment arm.

Conclusions:: Diode CPC and tube shunt as secondary interventions following primary tube shunt for refractory childhood glaucoma showed similar efficacies for glaucoma control. Observed complication rates were similar in both groups although better visual outcomes were found in the CPC group. This retrospective study supports use of either diode CPC or tube shunts following failure of an initial tube shunt for acceptable IOP control in refractory childhood glaucoma.

Keywords: intraocular pressure