Intravitreal plasmin without vitrectomy for macular edema secondary to branch retinal vein occlusion

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.

Prospective, comparative, interventional case series.

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.

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.

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.