Abstract
Purpose: :
To assess the efficacy of a single intravitreal injection of triamcinolone acetonide (IVTA) in patients with refractory diabetic macular edema (DME) unresponsive to prior intravitreal bevacizumab (IVB).
Methods: :
We retrospectively review the charts of 13 patients (13 eyes) with DME who had been previously treated with three consecutive IVB (1 mg/0.04 ml) performed on a monthly basis. Due to lack of significant functional and anatomical response to IVB the patients underwent a single IVTA (4 mg/0.1 ml). Main outcome measures were changes in best corrected visual acuity (BCVA) and in central retinal thickness (CRT) on OCT.
Results: :
Mean patients’ age was 49.6 years (range 28-70) and mean DME duration was 36 months (range 12-60). All patients except 3 received prior macular laser, IVTA or a combination of the two, at least 6 months before starting IVB. All patients had received prior full or sectorial panretinal photocoagulation. Following 3 IVB mean visual acuity (VA) increased from 49 ETDRS letters (0.7 LogMAR) at baseline to 53, 54 and 53 letters at 1, 2, and 3 months (p=0,08, p=0,1, p=0.2). CRT at baseline was 545 µm. It slightly decreased to 533 µm at 1 month then progressively increased to 557 µm at 3 months (p=0,9, p=0,3, p=0,6). Mean time gap between the last IVB and IVTA was 3 months (range 1-7). Baseline VA and CRT before IVTA were 50 letters (0.7 LogMAR) and 591±213 µm respectively. One month after IVTA visual acuity increased significantly to 56 letters (0.6 LogMAR) (p=0,004) and CRT on OCT decreased to 254±83 µm (p=0,001). No IOP increase occurred during IVB course while 4 patients developed ocular hypertension following IVTA. In all cases IOP was kept under control with topical medications. No retinal detachment or endophthalmitis were observed.
Conclusions: :
One single IVTA may offer certain advantages over bevacizumab in the short-term management of refractory DME, specifically with respect to changes in CRT. Visual improvement was not of the same magnitude as CRT decrease. Considering the positive functional and anatomical results obtained with IVB in patients with naïve DME by other authors, it could be hypothesized that in the pathogenesis of long-term, refractory DME, mainly in patients with prior PRP, inflammatory mechanisms play a predominant role compared to VEGF.
Keywords: diabetic retinopathy