13. • Prevalence of Diabetic Retinopathy
• The prevalence rate for retinopathy for all adults with diabetes aged
40 and older in the United States is 28.5% (4.2 million people);
worldwide, the prevalence rate has been estimated at 34.6% (93
million people).
• An estimate of the prevalence rate for vision-threatening diabetic
retinopathy (VTDR) in the United States is 4.4% (0.7 million people).
Worldwide, this prevalence rate has been estimated at 10.2% (28
million people).27,28
Assuming a similar prevalence of diabetes
mellitus, the projected prevalence of individuals with any diabetic
retinopathy in the United States by the year 2020 is 6 million
persons, and 1.34 million persons will have VTDR.
83. Keith–Wagener–Barker
Classification System
• In Grade 1, there’s a mild narrowing of the retinal artery.
• Grade 2 is similar to grade 1, but there’s more severe or
tighter constrictions of the retinal artery.
This is called arteriovenous, or AV, nipping.
• Grade 3 has the signs of grade 2,
but there’s also retinal edema,
microaneurysms,
cotton-wool spots
retinal hemorrhages (bleeding).
• Grade 4 has severe signs of grade 3
optic disc swelling called papilledema and macular edema.
People with grade 4 retinopathy have a higher risk for stroke
and may have kidney or heart disease.