Peripheral choriovitreal neovascularization in proliferative diabetic retinopathy: Histopathologic and ultrastructural study

We describe the histopathologic and ultrastructural evidence of choriovitre al neovascularization in the peripheral fundus of a non-vitrectomized eye w ith proliferative diabetic retinopathy (PDR), One eye with PDR was surgical ly enucleated because of neovascular glaucoma and studied with light and el ectron microscopy. The eye had neovascular membranes at the ora serrata of the peripheral fundus, The newly formed vessels originated from the choroid , passed through Bruch's membrane and the retina, and extended into the vit reous, These vessels had either developing or mature characteristics. The e ndothelial cells of the developing vessels contained a bulky cytoplasm with many intracytoplasmic filaments, ribosomes and rough endoplasmic reticulum . Budding endothelial cells were frequently found in the developing vessels , The endothelial cells of the mature vessels had attenuated cytoplasm and fenestrations with diaphragms, These observations suggest that choriovitrea l neovascularization in the peripheral fundus is one of the features of PDR .