Photodynamic therapy to control fibrosis in human glaucomatous eyes after trabeculectomy: A clinical pilot study

Objective: To evaluate the safety, tolerability, and clinical effect on intraocular pressure (IOP) of a carboxyfluorescein ester as an adjunctive antifibrotic therapy in human glaucomatous eyes to control postoperative wound healing after trabeculectomy. Methods: In 10 human glaucomatous eyes with high IOPs that underwent 1 to 3 previous surgical procedures for glaucoma, 2′7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester was applied 15 minutes prior to trabeculectomy via a subconjunctival injection followed by intraoperative illumination with diffuse blue light (450-490 nm; approximately 51.9 × 10³ candelas/m²) for 8 minutes. Antifibrotic efficacy was established by clinical response, postoperative IOP reduction, slitlamp examination, and filtering bleb site photographs. Success was defined as an IOP less than 21 mm Hg from baseline without the eye receiving any antiglaucomatous medication or an application of antimetabolites. Results: The mean (SD) IOP on the day before surgery was 37.2 (11.2) mm Hg. The IOP was 16.6 (3.8) mm Hg in 8 successful eyes after a mean (SD) follow-up of 400.1 (38.1) days (P<.001). Two eyes showed scarring at the site of the filtering bleb within 1 month. In 1 eye with pseudoexfoliation glaucoma IOP decreased to 17 mm Hg but needed topical antiglaucomatous medication. Clinical examination revealed none of the following: blebitis, uveitis, endophthalmitis, or toxic damage of the adjacent tissues. Conclusions: We report our findings about the first 10 consecutive human glaucomatous eyes treated with a single dose of 80 μg of 2′7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester during trabeculectomy. In contrast to chemotherapeutic agents, cellular photoablation acts only on cells having incorporated 2′7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester and having been exposed to light of an appropriate wavelength. Though safety and efficacy demand a controlled randomized study, our method seems to be an effective therapeutic approach to control postoperative fibrosis in human glaucomatous eyes with a poor surgical prognosis. Multiple factors such as dose of light, means of application, wavelength, irradiation area, total dose of the dye, and multiple dosing may be altered in the future to improve the antifibrotic effect of photodynamic therapy during surgery for glaucoma.