Diabetes increases the risk of a range of eye diseases, but the main cause of blindness associated with diabetes are diabetic retinopathy (DR) and diabetic macular oedema (DMO).
DR is caused by damage to blood vessels inside the retina at the back of the eye. With DMO, fluid accumulates in the macula, the central part of the retina, sometimes leading to vision loss.
Diabetic eye disease commonly affects both eyes and can lead to vision loss if it is not treated. Poorly controlled blood sugars, high blood pressure and high cholesterol increase the risk of developing DR and DMO.
Increased urbanization, the consumption of less-nutritious foods, more sedentary lifestyles and resulting obesity have all contributed to the dramatic rise in the global prevalence of diabetes, particularly in resource-poor countries.
Every person living with diabetes is at risk of developing diabetic retinopathy (DR). Poorly controlled blood sugars, high blood pressure and high cholesterol increase the likelihood of vision loss due to DR, along with the risk of associated vision disorders such as cataract or glaucoma.
Over time, poor glycemic control can result in improper growth or blockage of blood vessels that nourish the retina and lead to leakage of blood, fluids and the formation of lipid deposits in the eye. In more advanced forms of DR, new abnormal vessel growth occurs due to reduced oxygen flow caused by damaged or blocked vessels. The resulting retinal scarring, retinal detachment, along with fluid build-up and swelling in the central part of the retina (the macula), lead to impaired vision. Damage to the retina is often irreversible in the later stages of the disease and results in blindness.
In 2019, approximately 463 million people – or 1 in 11 adults world-wide – were living with diabetes, compared to 108 million in 1980.
Because diabetic retinopathy is initially asymptomatic many people with diabetes are not aware that their condition, if left unmanaged it may affect their vision and lead to blindness. Most patients who develop diabetic retinopathy have no symptoms until the very late stages (by which time it may be too late for effective treatment).
Approximately 1 in 3 people living with diabetes have some degree of diabetic retinopathy and 1 in 10 will develop a vision threatening form of the disease.
The Vision Loss Expert Group estimated that in 2020, 1 million people around the world were blind due to diabetic retinopathy, and over three million had moderate-severe vision impairment.
Low- and middle-income countries account for approximately 80% of the global diabetes burden yet many are ill equipped to properly identify, treat and manage the complex and varied consequences of this disease.
Efforts to reduce the prevalence of diabetes or to manage its health consequences more effectively are further undermined by the fact that approximately 50% of people with diabetes are currently undiagnosed.
