Intravitreal plasmin without associated vitrectomy as a treatment for refractory diabetic macular edema.

OBJECTIVE

To determine the effectiveness of a low-dose intravitreal injection of autologous plasmin enzyme (APE), without the performance of a vitrectomy, as a treatment for refractory diffuse diabetic macular edema (DDME).

DESIGN

Prospective, comparative, interventional case series.

PATIENTS

Sixteen patients with bilateral DDME who had not responded to prior laser photocoagulation. All patients received an injection in 1 eye, while the other eye served as a control.

INTERVENTION

Intravitreal 0.2 mL APE injection under topical anesthesia. The APE was obtained using a simplified method.

MAIN OUTCOME MEASURES

Central macular thickness (CMT) at 1 and 6 months, determined by optical coherence tomography (OCT) and best corrected visual acuity (BCVA).

RESULTS

All patients underwent a 1-month follow-up. Prior to injection, CMT in the eye about to receive the injection was 541 +/- 79 microm (mean +/- standard deviation [SD]) versus 535 +/- 76 microm in the control eye. One month after injection, CMT was 241 +/- 47 microm in injected eyes and 530 +/- 85 microm in control eyes (P < 0.001, bilateral Wilcoxon test for paired samples). The macular edema (ME) improved in all injected eyes (100%), with complete resolution in 7 patients (44%). The mean BCVA of treated eyes was 0.618 +/- 0.27 (mean +/- SD) at baseline and 0.45 +/- 0.24 four weeks after injection (paired samples t-test, P < 0.001). No adverse effects were observed in any of the patients. BCVA and CMT were stable when evaluated at 6-month follow-up (0.43 +/- 0.242 and 244 +/- 46 microm, respectively).

CONCLUSIONS

Intravitreal APE injection effectively reduces macular thickening due to DDME in cases that fail to respond to conventional laser photocoagulation, and improves visual acuity in a short term, and this results remain stable in a medium term what is very important. Further investigation is warranted in order to assess long-term efficacy and safety.