2020–2021 BCSC Basic and Clinical Science Course™
12 Retina and Vitreous
Part II: Disorders of the Retina and Vitreous
Chapter 05: Retinal Vascular Disease: Diabetic Retinopathy
Terminology and Classification
Diabetic Retinopathy Terminology
Diabetic retinopathy is classified according to a severity scale based upon its clinical features. In nonproliferative diabetic retinopathy (NPDR), intraretinal vascular changes are present but there is no development of extraretinal fibrovascular tissue; NPDR is staged across a spectrum of severity as mild, moderate, or severe. Although NPDR has been referred to as background diabetic retinopathy, this term is no longer recommended. The most advanced level of diabetic retinopathy, which can develop after an eye has progressed through the sequential stages of NPDR, is proliferative diabetic retinopathy (PDR). PDR is defined by the presence of retinal neovascularization resulting from diabetes-induced ischemia and is clinically staged as either early PDR or PDR with high-risk characteristics. Diabetic macular edema (DME), or swelling of the central retina, results from abnormal vascular permeability and can develop in patients with any severity level of diabetic retinopathy. DME is classified as center-involved (or central-involved) DME if the central 1 mm–diameter retinal subfield is thickened on optical coherence tomography (OCT); it is classified as non–center-involved DME if retinal thickening occurs only outside the central retinal subfield. Clinically significant diabetic macular edema (CSME) is an older definition for macular edema that meets certain severity criteria for size and location.
In the BCSC, study results are reported using the terminology of the particular study being described, even though such usage may not conform to current terminology.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.