Nasal preretinal neovascularisations have been observed to develop at least two weeks earlier than those on the temporal side in more than a third of premature babies with retinopathy of prematurity (ROP) stage 3, weighing between 690 and 1030 g. All these babies were assigned for cryotherapy. This interesting observation is discussed in relation to retinal vascular development and the pathogenesis of ROP.