Contact Transscleral Cyclodiode Laser Treatment for Refractory Glaucoma After Penetrating Keratoplasty: Retrospective Long-term Outcomes

: PReCIS:: This is a retrospective study with long-term follow-up using transscleral cyclodiode laser photocoagulation (TCP) with low complication rate and good graft survival and intraocular pressure (IOP) control. Selective 180-degree TCP may offer a good IOP control with reduced complication rates. PURPOSE: To study the long-term safety and efficacy of contact TCP in eyes with refractory glaucoma after penetrating keratoplasty (PKP). PATIENTS AND METHODS: All consecutive patients who were treated with TCP for refractory glaucoma following PKP between March 1996 and February 2017 in a tertiary corneal transplantation service in the United Kingdom. Only patients with a follow-up of 5 years were included. Eligible patients were identified through the corneal transplantation service database. Medical records and database data were retrospectively analyzed and compared at 5 years from baseline. RESULTS: In total, 28 eyes of 28 patients presented with a mean IOP of 30.4 mm Hg (SD, 7.5) at baseline despite maximally tolerated topical and systemic antiglaucoma medications. IOP was reduced significantly to 12.8 mm Hg (SD, 3.6) (P<0.0001) at 5 years with 100% of patients with a successfully controlled IOP (defined as ≤21 mm Hg). All patients had a clear graft at the beginning of the study period and at 5 years 60.7% (n=17) still presented clear grafts. The average number of topical glaucoma medication was reduced from 2.8 (SD, 0.8) to 1.7 (SD, 1.2) (P=0.019) at 5 years. Visual acuity remained stable in 67.9% of patients at 5-year endpoint. No complications (ie, hypotony or phthisis bulbi) were reported during the study period and the corneal graft failure rate remained low at 5 years (39.3%). CONCLUSIONS: Cyclodiode laser treatment with initial selective 180-degree protocol seems to be an efficient therapeutic option in the management of patients with refractory glaucoma post-PKP when compared with other surgical alternatives. A selective 180-degree protocol seems to potentially reduce the rate of complications. Further randomized controlled studies are needed to compare outcomes with modified treatment's protocols and glaucoma drainage device.