Retinectomy (Charles 1978) is defined as removing all retina, vitreous, and epiretinal membrane anterior to a circumferential, relaxing retinotomy (Machemer 1978). Retinectomy produces less hypotony than relaxing retinotomy probably because of debulking of proliferating retinal pigment epithelial (RPE) and glial cells as well as elimination of substrate (scaffold), extending from the posterior edge of the vitreous base anteriorly to the ciliary body.