Glucocorticosteroids and Postradiation Macular Edema: Rationale for Choice of Therapy and Efficacy of Use

Purpose. To substantiate and study the effectiveness of intravitreal injection of dexamethasone implant (“Ozurdex”) based on OCT study of morphostructural biomarkers of post-radiation macular edema (PMO) in different terms of its detection. Patients and methods . 28 patients with PMO after Ru-106 ± Rh-106 (BT) brachytherapy for choroidal melanoma (CM). Study group (IG 1) — 18 patients with PMO detected up to 9 months after BT, IG 2 — 10 patients with PMO detected 9 months or more after BT. OCT parameters studied: height of foveolar and parafoveolar zones, presence of neuroepithelium detachment, disorganization of inner layers, hyperreflective foci, pigment epithelium atrophy, as well as the form of edema (diffuse, cystic) and ellipsoid zone disorder. Intravitreal injections of dexamethasone implant (“Ozurdex”) were used as drug therapy of PMO. The results showed that OCT morphostructural changes such as neuroepithelial detachment were significantly more frequent in patients with PMO diagnosed before 9 months, while hyperreflective foci, disorganization of the inner retinal layers, and ellipsoid zone disorder were more frequent in the comparison group. At the same time, there was no statistically significant difference in the macular and parafoveal edema height, frequency of edema form and presence of such a sign as pigment epithelium atrophy in both groups. Evaluation of the efficacy of intravitreal injection of “Ozurdex” implant in both groups showed that after 1–2 months from the beginning of treatment in the group with early detection of PMO complete regression was obtained in all patients, while in the second studied group complete regression occurred only in one third of patients. The regression of PMO was accompanied by improvement of BCVA in the first group from 0.4 to 0.7, in the second group — from 0.3 to 0.6. Out of 28 patients, 3 patients required re-injection of the implant in average 11 months after the first injection. Conclusion. The OCT biomarkers of PMO should be considered in treatment planning and subsequent dynamic follow-up. Early diagnosis of PMO, as well as the use of intravitreal dexamethasone implant (“Ozurdex”) determines high efficiency of treatment and maximum visual rehabilitation of patients.