Diabetes mellitus

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Last staff update: 23 December 2020

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PubMed Search: Diabetes mellitus [title] retina pathology

Nat Pernick, M.D.
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Cite this page: Pernick N. Diabetes mellitus. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyeretinadiabetes.html. Accessed September 21st, 2023.
Definition / general
  • Common cause of blindness in Western society
  • Classified as background, preproliferative or proliferative retinopathy
  • Background retinopathy: initial lesion is capillary microangiopathy
  • Preproliferative retinopathy: changes of background diabetic retinopathy plus significant venous dilation / beading, cotton wool spots (due to focal infarcts in nerve fiber layer), extensive formation of intraretinal microvascular abnormalities (due to vascular shunts) and extensive ischemia
  • Proliferative retinopathy: growth of neovascular tissue from inner surface of retina into vitreous; causes retinal detachment, treat with laser photocoagulation; may occur without clinically visible background diabetic retinopathy
  • Retinopathy is associated with duration of diabetes - 60% at 15 years
  • May cause rubeosis iridis (neovascularization of iris) and secondary glaucoma
  • Also causes thickening of basement membrane of pars plicata of ciliary body
  • Also causes vacuolization of iris pigment epithelium with glycogen containing vacuoles related to blood glucose level at time of enucleation
Microscopic (histologic) description
  • Background retinopathy: retinal capillary microaneurysms and cotton wool spots (due to hypoxia from microvascular obstructions and nonperfusion) with PAS+ deposits on endothelium, basement membrane thickening, loss of pericytes; also venous anomalies, hemorrhage (flame shaped between fibers of nerve fiber layer), exudates (hard, yellow, waxy protein and lipid of outer plexiform layer appears eosinophilic) and edema
  • Proliferative retinopathy: new vessels that sprout from existing vessels on surface of optic nerve head or retina and penetrate the internal limiting membrane of the retina; thickened basement membrane, reduction in number of pericytes (causes microaneurysms and arteriovenous shunts)
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