Effects of dexamethasone intravitreal implant on macular morphology, macular function, retrobulbar blood velocity and oxygen saturation in retinal vessels in patients with macular edema secondary to retinal vein occlusion

Abstract

Purpose: To evaluate the effects of Dexamethasone (Ozurdex®) on macular morphology, macular function, retrobulbar blood velocity and oxygen saturation in retinal vessels in patients with branch vein occlusion or central vein occlusion after 6 months.

Methods: 25 patients with macular edema secondary to branch vein occlusion and 15 patients with central vein occlusion were included in the prospective study. Visual acuity using ETDRS charts and central macular thickness using a high resolution OCT were tested at each monthly study visit. Microperimetry was performed at baseline, at month 3 and month 6. Retrobulbar blood velocity using colour doppler imaging and oxygen saturation in retinal vessels using a Retinal Vessel Analyzer were compared between baseline and month 6.

Results: Visual acuity increased significantly from 64 letters to 72 letters (p<0.05 baseline vs month 6). Central retinal thickness decreased significantly from 533µm to 303µm at month 6 (p<0.01). Visual function measured using microperimetry tended to increase slightly between baseline and month 3 and didn't change between month 3 and month 6. At month four 22 patients required retreatment, at month five 8 patients and at month six 1 patient, respectively. Retinal diameters and oxygen saturation in retinal vessels did not change significantly (baseline versus month 6) Retrobulbar blood velocities didn't change comparing baseline to 6 months values. Increases in intraocular pressure (IOP) were measured in 30% of the included patients. None of the patients required cataract surgery during the first six months of the study.

Conclusions: Dexamethasone intravitreal implant seems to be effective in the treatment of macular edema secondary to retinal vein occlusion. Retreatment was required at month 4 in 22 of the 40 patients under study. Oxygen saturation in retinal vessels and retrobulbar blood velocities didn't change comparing baseline to month 6.