Purpose: To evaluate the morphological and functional changes following intravitreal Ozurdex (dexamethasone implant) injections in patients with macular oedema (MO) secondary to retinal vascular diseases.
Design: This is a single centre, exploratory phase III, prospective, open-label clinical study.
Methods: Thirty patients with MO secondary to retinal vascular disorders underwent assessments for best corrected visual acuity, contrast sensitivity, microperimetry, chromatic sensitivity, macular thickness, and morphology using spectral domain optical coherence tomography (SD-OCT) and fluorescein angiography at baseline. They were treated with intravitreal Ozurdex at baseline and monitored monthly with visual acuity and SD-OCT assessments up to 36 weeks. Re-treatment was permitted from 16 to 24 weeks according to pre-defined criteria. All visual function tests were repeated at 24 weeks.
Results: The mean change in central sub-field thickness (CST) from baseline was significant at all visits up to 32 weeks. The lowest mean CST was recorded at 8 weeks and the highest mean ETDRS score was achieved at 12 weeks. All visual functions except contrast sensitivity improved significantly by 24 weeks. The study showed that the ideal re-treatment time point based on functional and structural outcomes and known side-effects of Ozurdex treatment is at 20 weeks.
Conclusion: Ozurdex therapy has a rapid and dramatic effect on the macula for about 8 weeks followed by a sustained modest effect up to week 32. The optimal re-treatment time point is at 20 weeks.