Outcomes for common retinal diseases such as neovascular age-related macular degeneration (AMD) and diabetic macular edema (DME) have been relatively straightforward to assess, as the disease progresses on a time scale of months and treatment effects, such as that due to intravitreal anti-vascular endothelial growth factor (anti-VEGF), similarly take place over months or even weeks (Wells et al., 2016; Mitchell et al., 2018). This evidence concerns the gene VEGFA and diabetic macular edema.