Cyclodiode photocoagulation for refractory glaucoma after penetrating keratoplasty

Abstract

Objective This study analyzes the results of intraocular pressure (IOP) reduction by contact diode cycloablation (cyclodiode) in cases of refractory glaucoma after penetrating keratoplasty. Design Retrospective noncomparative, interventional case series. Participants Twenty-eight eyes in 28 patients attending the Moorfields Eye Hospital. Intervention Cyclodiode (40 applications × 1.5 W × 1.5 seconds over 270–300°) was used to control the IOP in refractory glaucoma after penetrating keratoplasty. Main outcome measures Postoperative IOP, graft status, visual acuity, and number of antiglaucoma medications were recorded after cyclodiode treatment. Results Cyclodiode resulted in a reduction of IOP from a median of 33 mmHg (interquartile range [28, 40.5]) to a median of 15 mmHg (interquartile range [12, 20.5]). Most patients had a significant lowering in IOP with a median reduction of 16 mmHg (interquartile range [12, 25]; P < 0.0001). IOPs of 6 to 21 mmHg were achieved in 22 patients (79%). Sixteen patients (57%) required more than one treatment with cyclodiode to control the IOP, with three patients (11%) requiring three treatments and two patients (7%) requiring four treatments. Visual acuity improved (> two Snellen lines of acuity) in three patients (11%) and remained the same (± one Snellen line) in 17 patients (61%). The mean number of antiglaucoma medications before cycloablation was 2.6 and was 1.8 after treatment ( P < 0.001). Of the 19 patients (68%) with originally clear grafts, three grafts (16%) developed opacification. One patient (4%), with a history of nanophthalmos and recurrent uveal effusion, had delayed hypotony (IOP < 6 mmHg) occurring 46 months after the diode treatment. All patients had at least 6 months follow-up. Conclusions These patients have often undergone multiple previous complicated ocular interventions and are often not suitable for filtration surgery. Reduction of IOP with maintenance of visual acuity and a good safety profile was achieved in most patients in this study but may require multiple treatments. We propose cyclodiode as an effective treatment for many patients in the management of refractory glaucoma after penetrating keratoplasty.