Clinical Characteristics Associated with the Development of Cystoid Macular Edema in Patients with Cytomegalovirus Retinitis.

We evaluated the incidence and characteristics of eyes with cytomegalovirus (CMV) retinitis according to the occurrence of cystoid macular edema (CME) and identified the risk factors of its occurrence. Patients diagnosed with CMV retinitis and examined using optical coherence tomography were classified according to the development of CME. The CME group was further divided according to the presence of active retinitis at the time of CME development. The demographics, serologic findings, ophthalmic presentations, ocular treatments, and visual prognosis were compared. CME was identified in 25 eyes (17 eyes with active retinitis and 8 eyes with inactive retinitis) out of the 67 eyes with CMV retinitis. Visual acuity was worse in the CME group than in the non-CME group. The CME group had longer CMV viremia duration, zone 1 involvement, and larger extent of CMV retinitis. While CME with concurrent active retinitis developed in eyes with direct foveal involvement of retinitis in the acute phase and required more ganciclovir injections after CME development, CME without active retinitis developed in eyes with larger extents of involvement and more intravitreal ganciclovir injections before CME development. Zone 1 involvement and longer CMV viremia duration were independently associated with the occurrence of CME. CME, which caused visual deterioration, developed in considerable patients with CMV retinitis and had different characteristics according to the presence of active retinitis.