Predictive Value of OCT-Controlled Early Response of Macular Edema Secondary to Retinal Vein Occlusion After Intravitreal Bevacizumab Therapy

Abstract

The goal of this study was to examine the response of macular edema (ME) secondary to retinal vein occlusion (RVO) to predict macular edema course and re-injection intervals. Twenty-four eyes from 24 patients with ME secondary to RVO, both central (CRVO) and branch (BRVO), were retrospectively included. All eyes received intravitreal bevacizumab therapy (1.25 mg/0.1 ml). Repetitive optical coherence tomography (OCT) examinations were performed to document the early macular edema response to treatment and the course of the disease during the first three monthly injections until the last follow-up 105 days after the first injection. A significant ME reduction is present as early as three hours after the first injection of bevacizumab. This significant reduction of central retinal thickness (CRT) is present until the third post-injection day. The greatest reduction occurs during the first 24 hours. Patients who reach a CRT less than 300 µm after 24 hours (day 1) have no recurrence after 30 days. Patients with a CRT over 300 µm on day 1 have a 50% rate of recurrence after 30 days. The favorable results of the first group are still present during the last follow-up examination, 105 days after the first injection. An OCT examination, 24 hours after the first bevacizumab injection, has a prognostic value and can identify the patients that can tolerate longer intervals between injections, this results in fewer bevacizumab injections during the course of the disease. This way an individualization of the treatment, opposed to a fixed therapy pattern, can be implemented. Also, patients with poor prognosis can be identified early and treatment can be altered or intensified accordingly.