Efficacy of posterior sub-Tenon’s capsule injection compared to intravitreal injection of triamcinolone acetonide for treatment of diabetic macular edema: A systematic review and meta-analysis

Abstract Background Diabetic macular edema (DME) is defined as a retinal thickening in one-disc diameter (DD) of the centre of the macula. It is a number of microvascular retinal changes that lead to blood–retinal barrier (BRB) disruption, causing leakage of fluid and plasma components into the inner and outer plexiform layers. Aim of the Work to conduct a systematic review and a meta-analysis estimating the efficacy and complications of posterior sub-Tenon’s capsule injection of triamcinolone acetonide (STTA) compared to intravitreal injection of triamcinolone acetonide (IVTA) for management of DME. Materials and Methods A comprehensive literature search was conducted using the databases Google scholar, PubMed, MEDS, web of science, EMBASE and Cochrane Library for published studies from 1 January 2000 to 1 September 2019.This meta-analysis included ten studies. They were randomized controlled clinical trials (RCTs), and about 343 patients with DME (469 eyes) participated in these studies. Results : This study demonstrated a statistically significant change in the mean of best corrected visual acuity (BCVA) improvement and central macular thickness (CMT) reduction in both groups when comparing the baseline to one- and three-month follow-ups after the injection, though with no statistically significant difference in the IVTA compared to the STTA group. At a six-month follow-up, both groups showed no significant differences in the BCVA and CMT compared to the baseline. Both groups showed no statistical differences in the BCVA or CMT over the follow-up periods. Regarding intraocular pressure (IOP) changes, the present study showed that the mean IOP was elevated in both groups at one- and three-month follow-ups after the injection compared to their baseline. There was a statistically significant difference between both groups at one and three-months. The IOP was more elevated in the IVTA compared to the STTA group. At a six-month follow-up, both groups showed no significant difference in the IOP elevation compared to the baseline. IOP elevation was the most reported adverse effect in all included studies. Cataract formation is also reported in some studies, though no other complications, such as endophthalmitis, vitreous hemorrhage (VH), and/or retinal detachment (RD), are reported in any of the studies. Conclusion : STTA injection has a comparable effect to the IVTA injection and carries a lower risk of intraocular complications. It is considered an easy, safe, and valid alternative to the intravitreal injection for the treatment of DME.