Based on clinical trial data, the prevalence of retinal vein occlusion in patients receiving MEK inhibitor therapy is 0.5%, which is higher than the 0.1% prevalence in the general population.36 The increased incidence could be related to MEK inhibitor therapy, but it could also be secondary to confounding factors such as hyperviscosity related to their underlying disease. This evidence concerns the gene MAP2K7 and retinal vein occlusion.