Rebound Effect After Intravitreal Dexamethasone Implant for the Treatment of Macular Edema Secondary to Central Retinal Vein Occlusion

Aim: To report on the rebound macular edema (ME) effect following dexamethasone implant for the treatment of nonischemic central retinal vein occlusion (CRVO). Methods: Twenty-one patients affected by ME secondary to central retinal vein occlusion (CRVO) underwent an implant of dexamethasone (700 mg) in a compassionate use program. The patients were followed up monthly. The Early Treatment Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA), central retinal thickness (CRT) on optical coherence tomography (OCT), and intraocular pressure were registered at monthly intervals. Retreatments were carried out on a pro-re-nata (PRN) basis starting from the third month. Results: Both BCVA and CRT improved in all cases. A rebound effect, characterized by a recurrence of ME in excess of the baseline value, occurred in 3 cases (13%) at months 3 and 4. Visual acuity accordingly dropped at the higher CRT values in the 3 cases displaying the rebound effect. Additional treatment with dexamethasone implant led to both a recovery in visual acuity and reduction in CRT. Conclusions: A rebound effect can occur after dexamethasone implant for the treatment of ME related to CRVO, but does not affect functional or anatomical recovery when retreatment is provided. The retreatment rate with dexamethasone implant should be adapted to suit the patient's response.