MKI67 and retinal detachment: In general, membranes identified as PVR had many more Ki-67-positive cells in comparison to those in the other three categories, with the average number of Ki-67-positive cells identified per mm2 of tissue being 20.9 for proliferative diabetic retinopathy, 138.3 for PVR, 12.2 for post–retinal detachment, and 19.3 for idiopathic ERM.