Intravitreal versus posterior subtenon injection of triamcinolone acetonide in treatment of diabetic macular edema

Abstract

Purpose: The aim of the study was to compare the efficacy and safety of intravitreal triamcinolone acetonide (IVTA) versus posterior subtenon injection of triamcinolone acetonide (PSBTA) for diabetic macular edema (DME). Materials and Methods: The study design was a prospective, interventional, randomized controlled study. Participants: The study participants were 26 patients (Thirty eyes) with DME and central subfield thickness (CST) >250 μm. Intervention: Eyes were randomly assigned to two equal groups; Group A received a single 4 mg IVTA and Group B received a 40 mg PSBTA. Four patients had bilateral DME; they received IVTA in one eye and PSBTA in another eye. Main Outcome Measures: Changes in visual acuity (VA) and CST obtained using optical coherence tomography were measured during a 3-month follow-up. Potential treatment complications were monitored including change in intraocular pressure (IOP). Results: The mean preoperative CST was 393.7 ± 93.0 μm and 351.5 ± 56.4 μm in Group A and B, respectively. Both groups showed comparable significant improvement in CST and VA at 1 and 3 months postinjection compared to preoperative values. The mean CST in Group A was 282.2 ± 65.0 μm compared to 284.0 ± 59.0 μm in Group B at 1 month (P = 0.910) and 276.3 μm ± 71.1 compared to 260.2 μm ± 63.3 at 3 months (P = 0.519). The mean VA in LogMAR in both groups at 3 months was 0.47 ± 0.23 and 0.32 ± 0.29, respectively (P = 0.142), compared to preoperative VA of 0.80 ± 0.19 and 0.68 ± 0.23, respectively. The preoperative IOP was 13.80 ± 2.07 in the IVTA group and 13.07 ± 1.83 in the PSBTA group. IOP showed significantly higher elevation in the IVTA group at 1 and 3 months (19.4 mmHg ± 1.35 and 19.0 mmHg ± 1.36) compared to the PSBTA (16.5 mmHg ± 1.40 and 16.2 mmHg ± 1.50) (P = 0.000). No eyes had IOPs >21 mmHg. Conclusions: Posterior subtenon injection of TA is a safe and valid alternative to the intravitreal injection for the treatment of DME having a comparable effect on VA and CST, yet a lower risk of IOP elevation.