Microvascular retinal disease from chronic hyperglycemia — leading cause of new-onset blindness in working-age adults.
Also known as: diabetic retinopathy, DR, NPDR, PDR, non-proliferative diabetic retinopathy, proliferative diabetic retinopathy, diabetic macular edema, DME
Overview
Microvascular complication of diabetes mellitus characterized by progressive retinal microaneurysms, hemorrhages, exudates, ischemia, and ultimately neovascularization. Classified as non-proliferative (NPDR — mild, moderate, severe) and proliferative (PDR — new vessels at the disc, NVD, or elsewhere, NVE). Diabetic macular edema (DME) — fluid in the central macula — can occur at any stage.
Epidemiology
Leading cause of new-onset blindness in US adults aged 20-74. Nearly all patients with type 1 diabetes for >20 years and most with type 2 develop some degree of retinopathy. Prevalence of vision-threatening retinopathy ~5-10% of diabetic patients.
🔒 Free preview limit reached
Keep reading — start your free trial
You've read your 2 free diagnosis previews. Create your free account to unlock the full Diabetic Retinopathy outline — plus all 514 diagnoses, 3,500+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
Pregnancy (can accelerate progression — exam at first prenatal visit)
Renal disease (proteinuria)
Smoking
Anemia, sleep apnea
Rapid intensive glycemic correction in long-standing poor control (transient worsening)
Pathophysiology
Chronic hyperglycemia drives advanced glycation end-product formation, polyol pathway flux, protein kinase C activation, and oxidative stress. These damage retinal capillary pericytes and endothelial cells, leading to microaneurysm formation, increased vascular permeability (edema and exudates), capillary nonperfusion (ischemia), and upregulation of VEGF. VEGF drives macular edema and, when ischemia is widespread, proliferative neovascularization. New vessels are fragile and grow along the posterior hyaloid, causing vitreous hemorrhage and tractional retinal detachment.
Clinical presentation
Symptoms
Often ASYMPTOMATIC until advanced or DME develops — emphasizes screening
Blurred or fluctuating vision (often with glycemic swings)
Floaters or sudden vision loss — vitreous hemorrhage from PDR
Curtain over vision — tractional retinal detachment
Central blurring or distortion — diabetic macular edema
ADA / AAO screening: dilated exam at diagnosis in type 2 DM and within 5 years of diagnosis in type 1 (and at puberty), then annually (or every 1-2 years if no retinopathy and good glycemic control). Pregnant diabetic patients: exam in first trimester and as indicated.
Labs
A1c, lipid panel, BMP, urine albumin-creatinine — for diabetic care, not specific to DR diagnosis
Diabetic macular edema (non-center-involving) — focal/grid laser per ETDRS
Intravitreal corticosteroid implant — dexamethasone (Ozurdex), fluocinolone (Iluvien) — for DME refractory to anti-VEGF or pseudophakic patients; cataract and IOP-rise risk
Proliferative DR — panretinal photocoagulation (PRP) — ablates peripheral ischemic retina to reduce VEGF drive (DRS); high-risk PDR is a class I indication
Anti-VEGF — non-inferior to PRP for PDR over 2 years (Protocol S), and preferred when DME coexists
Vitrectomy for non-clearing vitreous hemorrhage, tractional retinal detachment threatening macula, or combined tractional-rhegmatogenous detachment (DRVS)
Cataract progression and earlier need for cataract surgery
Worsened DR after rapid glycemic correction (transient — emphasize gradual normalization in chronically uncontrolled patients)
PANCE pearls
Early DR is silent — annual dilated exams or telehealth retinal photos are essential per ADA guidelines.
Macular edema can occur at any stage of DR — measure with OCT, not just slit-lamp.
PROLIFERATIVE DR = new vessels (NVD or NVE) and is the indication for PRP and/or anti-VEGF.
Anti-VEGF is now first-line for center-involving DME and is non-inferior to PRP for PDR, particularly when DME coexists (Protocol S).
Pregnancy can rapidly accelerate DR — screen at first prenatal visit and as indicated; gestational diabetes alone does not require retinal screening.
Fenofibrate slowed retinopathy progression independently of lipid effects in ACCORD Eye and FIELD — consider in patients with DR and dyslipidemia.
References
ADA 2024 — American Diabetes Association. Standards of Care in Diabetes — Retinopathy, Neuropathy, and Foot Care. Diabetes Care 2024;47(Suppl 1):S231-S243
AAO 2019 — American Academy of Ophthalmology. Diabetic Retinopathy Preferred Practice Pattern. Ophthalmology 2020;127(1):P66-P145
DCCT/EDIC — DCCT Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes. NEJM 1993;329(14):977-986
ETDRS — Early Treatment Diabetic Retinopathy Study Research Group. Photocoagulation for diabetic macular edema. ETDRS Report Number 1. Arch Ophthalmol 1985;103(12):1796-1806
Protocol S — Gross JG et al. Panretinal photocoagulation vs intravitreous ranibizumab for proliferative diabetic retinopathy. JAMA 2015;314(20):2137-2146
Practice EENT questions on FirstPassPA
Turn this outline into retention. 3,500+ board-style questions with an AI tutor that explains every answer — free to start, no card required.
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants.