Intravitreal triamcinolone acetonide versus combined intravitreal bevacizumab and dexamethasone in diffuse diabetic macular oedema

Background: To compare the efficacy of a single injection of combined intravitreal dexamethasone and bevacizumab (Avastin) with that of intravitreal triamcinolone acetonide in eyes with diffuse cystoid diabetic macular oedema. Design: Prospective, non-randomized, masked, interventional case series. Participants: Twenty-four eyes of 24 subjects with centre-involved diabetic macular oedema extending over two disc-areas with predominant cystic changes on spectral domain optical coherence tomography were selected. Methods: Ten phakic and two pseudophakic, ocular hypertensive eyes received intravitreal dexamethasone and bevacizumab as against 12 pseudophakic, normotensive eyes that received intravitreal triamcinolone acetonide. Main Outcome Measures: Change in central macular volume on spectral domain optical coherence tomography and best-corrected visual acuity were measured at 6-week follow-up. Results: Baseline data were matched in both groups. Post-injection central macular volume (7.46 +/- 0.73 mm(3)) was significantly lower (P < 0.001) in the intravitreal triamcinolone acetonide group when compared with its pre-injection central macular volume (9.11 +/- 1.0 mm(3)) or when compared with the post-injection central macular volume (P = 0.02) of the intravitreal dexamethasone and bevacizumab group (8.42 +/- 1.18 mm(3)). However, post-injection best-corrected visual acuity between the intravitreal triamcinolone acetonide (0.65 +/- 0.15 logMAR) and the intravitreal dexamethasone and bevacizumab groups (0.685 +/- 0.15 logMAR) was not significantly different (P = 0.06) at 6 weeks. No significant correlation was noted between change in central macular volume and change in best-corrected visual acuity (r = 0.35, P = 0.07) from the pooled data of both the groups. A fair correlation was noted between change in central macular volume and pre-injection central macular volume (r = 0.55, P = 0.005). Conclusions: Intravitreal triamcinolone acetonide may be more effective than intravitreal dexamethasone and bevacizumab in reducing macular volume in patients with diffuse cystoid diabetic macular oedema. A significant reduction in macular volume does not necessarily translate into a correspondingly significant improvement in best-corrected visual acuity.