Purpose: To evaluate retinal functional improvement by means of visual acuity and retinal sensibility examination after intravitreal dexamethasone implant in patients affected by cystoid macular edema secondary to retinal vein occlusion.

Cystoid macular edema represents the most important cause of visual impairment after retinal vein occlusion. The etiological factors of this complication are under investigation, from inflammatory cytokines to the breakdown of vascular barrier with increased permeability and diffusion of angiogenic factors. Clinical research developed different drugs and therapeutic strategies to treat and control macular edema, to evaluate the correct timetable and to reach long-term clinical significative results. At now, different experiences have been published with available drugs, from steroids to anti Vascular Endothelial Growth Factor. A debate still remains about the correct approach, the correct combination of drugs (if necessary) and the correct evaluation of drug effectiveness.

In our study, we will evaluate extensive functional recovery and its relation to macular thickness after steroid injection. Considering that visual acuity reflects only foveal function, it may not be sufficient to evaluate the overall function on the macular area. We introduce microperimetry study as a valuable and reproducible tool to create a functional mapping of the entire macula.

Inclusion criteria were: age older than 18 years; CME secondary to retinal vein occlusion, disease duration inferior to 12 weeks; best-corrected visual acuity (BCVA) between 20/200 and 20/25 (Snellen equivalent) in the study eye at baseline examination, central retinal thickness (CRT) superior to 300 mm, as measured by optical coherence tomography at baseline examination.

The exclusion criteria were any ocular surgery in the study eye in the past 6 months; diabetes mellitus with signs of diabetic retinopathy; previous laser photocoagulation; previous intravitreal injection of corticosteroids or anti-vascular endothelial growth factor; a history of ocular inflammation; marked retinal ischemia or retinal hemorrhages (in particular in macular region involving the fovea); any other ocular condition such as anterior ischemic neuropathy, amblyopia or significant media opacities; significant alteration on epiretinal surface such as epiretinal membrane or vitreomacular traction; uncontrolled or advanced glaucoma; any uncontrolled systemic disease.

Patients affected by cystoid macular edema (CME) due to retinal vein occlusion of recent onset (less than three months) were enrolled