Post-vitrectomy Macular Edema: Shedding Light on Incidence and Risk Factors

Post-surgical macular edema is a common cause of delayed visual recovery. Although its occurrence after cataract surgery is well known, the specifics on post-vitrectomy macular edema (PVME) are less readily available in the recent literature. This narrative review identifies a wide-ranging incidence due to heterogeneous surgical indications, study designs, and lack of diagnostic standards in the current literature. PVME requiring pharmacological treatment ranges from 2.0 to 27.3%. Higher rates of macular edema are encountered after vitrectomy for retinal detachment, retained lens fragments, and epiretinal membranes. The intraretinal cystic changes after epiretinal membrane removal, however, often represent remnants of tractional disease, rather than true macular edema. This review elaborates on several patient-related and surgical risk factors, mostly in retinal detachment surgery. Predisposing factors are redetachment, proliferative vitreoretinopathy, silicone oil tamponades, extensive retinopexy, and macular involvement in cases with a retinal detachment. Patients who undergo procedures for macular holes, vitreous floaters, and secondary lens implantation appear less susceptible to developing PVME. Furthermore, higher rates of PVME are seen after crystalline lens removal, both in combined phacoemulsification-vitrectomy and when cataract surgery is performed after the vitrectomy. Additional research should lead to improved risk assessment and a reduced burden of this clinical issue.