Aims To report the early development of epiretinal membranes (ERM) in eyes with retinal vein occlusions (RVO) treated with intravitreal bevacizumab and to describe possible mechanisms that may be involved in the growth and contraction of these lesions.

Methods Retrospective and interventional study that included 25 eyes of 25 patients with RVO (16 eyes with central retinal vein occlusion and nine eyes with branch retinal vein occlusion). After an initial 2.5 mg/0.1 ml intravitreal bevacizumab injection all patients were followed-up every 6 weeks. Re-treatments were based on visual acuity and optical coherence tomography findings.

Results Twenty-five eyes were treated with bevacizumab and followed for 8.3 (range 4.5–13.5) months. Four eyes developed an ERM within 6–7 weeks after the administration of bevacizumab. ERM was not associated with further deterioration of visual acuity or metamorphopsia in these patients. A rebound of macular oedema was observed in one patient with ERM and in two other patients. No other side effects were observed.

Conclusions Intravitreal bevacizumab may be associated with an early growth of ERM in eyes with RVO, although a causative relationship cannot be established. Future randomised clinical trials are necessary to determine the efficacy and safety profile of this novel therapy.