Objectives: To evaluate the effects and safety of intravitreal injections of autologous plasmin enzyme (APE), without vitrectomy, as a treatment for macular edema secondary to branch retinal vein occlusion.
Design: Prospective, comparative, interventional case series.
Methods: Patients were recruited and enrolled consecutively from February 1 through October 31, 2008, at the Retina Unit of the Hospital General Universitario, Valencia, Spain. An eye from 8 patients diagnosed as having macular edema due to branch retinal vein occlusion received an injection, after having received topical anesthesia, of 0.2 mL of APE, which had been obtained using a simplified method. Best-corrected visual acuity and central macular thickness measured by optical coherence tomography constitute the main outcome measures of the study.
Results: The mean (SD) central macular thickness decreased from 494.875 (68.82) to 226.375 (28.67) μm 1 month after APE injection and to 228.570 (21.53) μm after 6 months (P < .001). The best-corrected visual acuity (logarithm of the minimal angle of resolution) improved from a preoperative value of 0.552 (0.17) to 0.217 (0.087) (mean, 20/80-20/32, Snellen equivalent) at the end of follow-up (P < .01). No secondary effects were observed during 6 months of follow-up.
Conclusion: This pilot study suggests that intravitreal injection of APE as a treatment for macular edema secondary to branch retinal vein occlusion improves central macular thickness and best-corrected visual acuity and may be a safe and effective alternative therapy for this condition if confirmed in controlled trials compared with standard care with longer follow-up.