Retinopathy, Diabetic

Key Features

Essentials of Diagnosis

• Present in ~33% of all patients diagnosed with diabetes

• Present in ~20% of patients with type 2 diabetes patients at time of diagnosis of diabetes

• By 20 years after diagnosis of diabetes, 99% of those with type 1 diabetes and 60% of those with type 2 diabetes will have diabetic retinopathy

• Nonproliferative diabetic retinopathy

  • Can be mild, moderate, or severe

  • Microvascular changes are limited to the retina

  • Severe nonproliferative retinopathy is defined as having any one of

    • Severe intraretinal hemorrhages and microaneurysms in four quadrants

    • Venous beading in two or more quadrants

    • Intraretinal microvascular abnormalities in at least one quadrant

• Proliferative (new blood vessel growth) diabetic retinopathy

  • Blood vessels grow on the retina, optic nerve, or iris

• Diabetic macular edema

  • Central retinal swelling

  • Can occur with any severity level of diabetic retinopathy

  • Reduces visual acuity if foveal center is involved

General Considerations

• Present in about one-third of patients diagnosed with diabetes; about one-third of those have sight-threatening disease

• Prevalence and severity increase with longer duration and poorer control of diabetes

• In type 1 diabetes, retinopathy is not detectable for the first 5 years after diagnosis

• In type 2 diabetes, about 20% of patients have retinopathy at diagnosis, likely because they had diabetes for a long time before diagnosis

• Macular involvement is the most common cause of legal blindness in type 2 diabetes

• There are two main categories of diabetic retinopathy

  • Nonproliferative (previously known as "background")

    • Subclassified as mild, moderate, or severe

    • Diabetic macular edema can occur at any stage

    • Represents the earliest stage of retinal involvement in diabetes

  • Proliferative

    • Less common than nonproliferative but causes more severe visual loss

    • Involves the growth of new vessels and fibrous tissue on the surface of the retina, extending into the vitreous chamber

Demographics

• In the United States, it

  • Affects about 4 million people

  • Leading cause of vision loss worldwide among adults aged 25–74 years

  • The number of affected individuals aged ≥ 65 years is increasing

• Worldwide, affects approximately 93 million people, including 28 million with vision-threatening disease

Clinical Findings

• Nonproliferative retinopathy

  • Manifests as microaneurysms, retinal hemorrhages, venous beading, retinal edema, and hard exudates

  • In mild disease, retinal abnormalities are mild without visual loss

  • Reduction of vision

    • Most commonly due to diabetic macular edema, which may be focal or diffuse

    • Can also be due to macular ischemia

    • Interference with visual acuity in clinically significant macular edema (process of retinal capillaries leaking proteins, lipids, or red cells in macula)

  • Severe disease is defined as having any one of the following:

    • Severe intraretinal hemorrhages and microaneurysms in four quadrants

    • Venous beading in two or more quadrants

    • Intraretinal microvascular abnormalities in at least one quadrant

• Proliferative retinopathy

  • Characterized by ...