Evaluation of changes in epivascular glia before and after intravitreal dexamethasone implant: an OCT pilot study

Purpose: to detect changes in epivascular glia (EVG) in diabetic retinopathy after intravitreal dexamethasone implant using en face optical coherence tomography (enface OCT) and OCT angiography (OCTA) and to correlate improvements in functional and structural features. Methods: 38 eyes of 38 patients were enrolled in this prospective study. They were divided into two different study groups: the first group including 20 eyes with diabetic retinopathy type 1 complicated by macular oedema and the control group including 18 eyes from 18 healthy age-matched patients. The main outcome measures were: (i) differences at baseline in the foveal avascuar zone (FAZ) area in the study group versus control; (ii) the presence of epivascular glia in the study group versus control, (iii) differences at baseline between foveal macular thickness versus control; (iiii) changes in foveal macular thickness, FAZ and epivascular glia in the study group before and after intravitreal dexamethasone implant. Results: At baseline FAZ area detected at OCTA was larger in the study group than in the control group, and epivascular glia was only detected in the study group. Three months after intravitreal injection of dexamethasone implant in the study group the best corrected visual acuity (BCVA) improved and central macular tickness reduced (P<0.0001). No significant differences were found in FAZ area while epivascular glia disappeared in 80% of the patients after treatment. Conclusions: Glia activation due to retinal inflammation in diabetic retinopathy (DR) can be detected on en face-OCT as epivascular glia. Intravitreal dexamethasone (DEX) implant improves both the anatomical and functional condition in the presence of these signs.