Diabetic eye complications
Diabetic eye complications are chronic microvascular changes to the retina from prolonged hyperglycemia, ranging from nonproliferative diabetic retinopathy to vision-threatening proliferative retinopathy and diabetic macular edema, and are the leading cause of preventable blindness among working-age adults with diabetes. Diagnosis relies on scheduled dilated fundoscopic screening, and treatment centers on glycemic, blood pressure, and lipid control together with panretinal laser photocoagulation or intravitreal anti-VEGF injection for sight-threatening disease.
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What this article covers
- Overview
Diabetic eye complications encompass the retinal microvascular changes caused by prolonged hyperglycemia, principally diabetic retinopathy and its associated diabetic macular edema.
- Epidemiology
Roughly one-third of people with diabetes are estimated to have some degree of diabetic retinopathy, with risk rising the longer diabetes has been present.
- Risk factors
Longer duration of diabetes is the single strongest risk factor for both presence and severity of retinopathy.
- Pathophysiology
Chronic hyperglycemia damages retinal capillary endothelial cells and pericytes, leading to capillary occlusion and reduced retinal perfusion.
- Clinical features
Diabetic retinopathy is frequently asymptomatic in its early stages, which is precisely why scheduled screening (rather than symptom-triggered evaluation) is essential; symptoms typically emerge only…
- Differential diagnosis
Hypertensive retinopathy: shares flame-shaped hemorrhages, cotton-wool spots, and hard exudates, but is distinguished by arteriolar narrowing with copper- or silver-wire appearance and arteriovenous…
- Diagnosis
The clinching diagnostic basis is a dilated fundoscopic examination showing microaneurysms, hemorrhages, exudates, or neovascularization, staged as nonproliferative (mild, moderate, or severe) or…
- Management
First, optimize systemic risk factors in every patient, which prevents and delays progression at every stage: achieve glycemic targets (aware that rapid correction of longstanding poor control can…
- Complications
Vitreous hemorrhage from rupture of fragile neovascular vessels, causing sudden vision loss or floaters.
- Prognosis
Early detection through scheduled screening and prompt treatment substantially reduces the risk of permanent vision loss, which is why retinopathy is characterized as the leading cause of preventable blindness in this population.
- Prevention
Achieve and maintain glycemic targets from the time of diabetes diagnosis, since degree and duration of hyperglycemia are the dominant modifiable drivers of retinopathy risk.
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Type 1 diabetes mellitus is an insulin-deficient state from autoimmune (type 1A) or idiopathic (type 1B) destruction of pancreatic beta cells, presenting with hyperglycemia that can range from mild to life-threatening diabetic ketoacidosis. Diagnosis combines standard glycemic criteria with autoantibody testing (GAD65, IA-2), and lifelong insulin therapy, generally as a basal-bolus regimen, is required from diagnosis, with self-monitoring or continuous glucose monitoring to guide dosing.
- Type 2 diabetes mellitus
Type 2 diabetes is hyperglycemia from insulin resistance with progressive relative insulin deficiency, diagnosed by a hemoglobin A1c of 6.5% or higher, a fasting glucose of 126 mg/dL or higher, or a 2-hour oral glucose tolerance test value of 200 mg/dL or higher. First-line treatment is lifestyle modification plus metformin, with an SGLT2 inhibitor or GLP-1 receptor agonist added early for patients with atherosclerotic disease, kidney disease, or heart failure.
- Diabetic ketoacidosis
Diabetic ketoacidosis is a life-threatening hyperglycemic crisis of near-absolute insulin deficiency, most common in type 1 diabetes, producing an anion-gap ketoacidosis from unrestrained lipolysis and osmotic diuresis from severe hyperglycemia. It is diagnosed by hyperglycemia, ketonemia, and an anion-gap metabolic acidosis, and treated with intravenous isotonic saline, an intravenous regular insulin bolus and infusion, and aggressive potassium repletion guided by frequent electrolyte monitoring.
- Hyperosmolar hyperglycemic state
Hyperosmolar hyperglycemic state is a life-threatening hyperglycemic crisis of older patients with type 2 diabetes, marked by extreme hyperglycemia and profound dehydration without significant ketoacidosis, because residual insulin secretion suppresses lipolysis even as it fails to control glucose. It is diagnosed by marked hyperglycemia (often >600 mg/dL) with plasma hyperosmolality above 320 mOsm/kg and minimal ketosis, and treated with aggressive isotonic fluid resuscitation, intravenous regular insulin, and careful potassium repletion.