All this, combined with large periods of hyperoxia-hypoxia, Produces that the normal vascularization of the retina stops. This also produces vascular-occlusive changes, arteriovenous anastomoses in the edge of the vascularized with the none-vascularized retina (18), begins the formation of abnormal vessels towards the vitreous, finally lead to retina detachment in the most severe cases (2,3,4,5).