Photodynamic Modulation of Wound Healing in Glaucoma Filtration Surgery

Abstract

Aim: To report a clinical pilot study investigating photodynamic therapy (PDT) in combination with glaucoma filtration surgery. BCECF-AM was used as the photosensitising substance. The clinical safety and tolerability of BCECF-AM, and its efficacy in controlling postoperative intraocular pressure (IOP) were assessed. Methods: Before trabeculectomy (TE), 42 consecutive eyes of 36 glaucoma patients received one subconjunctival injection of 80 µg BCECF-AM (2,7,-bis-(2-carboxyethyl) -5-(and-6) -carboxy-fluorescein, acetoxymethyl-ester) followed by an intraoperative illumination with blue light (λ = 450-490 nm) for 8 minutes. Antifibrotic efficacy was established as postoperative IOP reduction of >20% and/or an IOP constantly < 21 mm Hg without antiglaucomatous medication. Follow up of the filtering bleb was documented by slit lamp examination. Results: Eyes had mean 1.1 preoperative surgical interventions (filtration and non-filtration glaucoma surgery). Mean preoperative IOP was 31.6 (SD 9.7) mm Hg. Patients were followed for mean 496 days (range 3.5-31.8 months). Of the 42 eyes, 25 eyes had an IOP decreased to 15.8 (3.4) mm Hg without medication (complete success: 59.5%; p<0.001; t test). Seven eyes showed good IOP reduction < 21 mm Hg under topical antiglaucomatous medication (qualified success: 16.7%). 10 eyes failed because of scarring within 2-67 weeks (23.8%). Clinical follow up examinations revealed no local toxicity, no uveitis, and no endophthalmitis. Conclusions: This method is a new approach in modulating postoperative wound healing in human eyes undergoing glaucoma filtration surgery. The data of the first human eyes combining TE with PDT underline the clinical safety of this method and its possible potential to prolong bleb survival. P ostoperative scarring of the filtering bleb is the most crucial factor in determining the short and long term outcome of modern glaucoma filtration surgery. Trabeculectomy (TE) is the preferred operation. However, in conventionally performed trabeculectomy, a large retrospective study has shown a failure rate of up to 30% within 3 months after surgery.