Purpose: To evaluate the immediate changes after intravitreous triamcinolone acetonide or intravitreous bevacizumab in diabetic macular edema (DME).
Methods: A nonrandomized interventional study. Type 2 diabetic patients were included. Intravitreous triamcinolone acetonide (4 mg) was injected for 22 eyes with DME and IVB (1.25 mg) for 18 eyes with DME. The early time-dependent changes of central macular thickness were evaluated by optical coherence tomography before and from 1 hour to 1 month after intervention. Intravitreous bevacizumab was also tested in patients with retinal vein occlusion as a control of non-DME. Visual acuity was also examined.
Results: Compared with the baseline, central macular thickness of eyes with DME decreased significantly 1 hour after intravitreous triamcinolone acetonide (P < 0.05, Wilcoxon signed rank test), while it did not significantly until 24 hours after IVB. The decrease in central macular thickness was observed significantly from 3 hours after IVB in retinal vein occlusion (P < 0.05, Wilcoxon signed rank test), and it was more evident in retinal vein occlusion than DME after IVB. Visual acuity improved significantly in DME with intravitreous triamcinolone acetonide or IVB at 1 month (P < 0.01 and P < 0.05, respectively, Wilcoxon signed rank test).
Conclusion: Factors responsive to triamcinolone acetonide, other than vascular endothelial growth factor, might play an important role in pathogenesis of DME compared with retinal vein occlusion. Although no conclusion can be drawn, immediate decrease in central macular thickness after intravitreous triamcinolone acetonide might indicate the possible involvement of a nongenomic pathway of triamcinolone acetonide action.