epidemiology

Last edited 12/2020 and last reviewed 12/2020

he risk of developing diabetic retinopathy is greater with longer duration of diabetes:

• large longitudinal studies of patients with diabetes in Wisconsin reported that
• retinopathy develops within five years of diagnosis of diabetes in about
• 25% of people with type 1 diabetes
• 40% of people with type 2 diabetes who are taking insulin and 24% of people with type 2 diabetes who are not taking insulin
• the 25 year cumulative rate of progression to
• diabetic retinopathy was 83%
• diabetic macular oedema was 29%
• clinically relevant macular oedema was 17% 
• in addition to duration of diabetes, poor glycaemic control and uncontrolled hypertension is also associated with greater risk of DR (when compared to patients with good control of these factors)  (2,3)
• control of serum glucose and blood pressure have been shown to be effective in preventing vision loss due to DR
• DR is the leading cause of vision loss in adults aged 20–74 years

Diabetic macular edema (DME) is the swelling of the retina resulting from the exudation and accumulation of extracellular fluid and proteins in the macula (3), due to the breakdown of the blood-retina barrier with an increase in vascular permeability (4)

• about a third of people with diabetes have DR, and 1 in 10 is affected by DME (5)
• Intraretinal fluid accumulation results in significant reduction invisual acuity that may be reversible in the short term, but prolonged edema can
  cause irreversible damage resulting in permanent visual loss

Reference:

• Cheung N, Mitchell P, Wong TY. Diabetic retinopathy. Lancet. 2010;376(9735):124–36.
• Klein R, Klein BE, Moss SE, Cruickshanks KJ. The Wisconsin epidemiologic study of diabetic retinopathy. XV. The long-term incidence of macular edema. Ophthalmology. 1995;102:7–16
• Ciulla TA et al. Diabetic retinopathy and diabetic macular edema: pathophysiology, screening, and novel therapies. Diabetes Care 2003;26(9):2653-64.
• Antcliff RJ, Marshall J. The pathogenesis of edema in diabetic maculopathy. Seminars in Ophthalmology 1999;14(4):223-32.
• Yau JW et al. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care 2012;35(3):556-64.