The researchers suggest poor control of blood glucose and inadequate access to eye health services in many parts of the world are contributing to the growing global burden of diabetes-related vision loss.
These figures are the result of an analysis by a global consortium, who recently published their work online in the journal Diabetes Care.
As the number of people living with diabetes worldwide grows, so does the chance that more people will develop diabetic retinopathy and suffer subsequent vision loss, especially if they do not receive or adhere to the care they need.
Diabetic retinopathy is a disease of the retina that damages sight as a result of chronic high blood sugar in diabetes. The high sugar damages the delicate blood vessels in the retina - the light-sensitive layer of tissue that lines the back of the eye.
As the damage increases, the blood vessels begin to leak and distort vision. In people with advanced diabetic retinopathy, new, abnormal blood vessels grow in the retina, causing further damage and eventually permanent scarring and vision loss or blindness.
Lead author Janet Leasher, associate professor of the College of Optometry at Nova Southeastern University in Fort Lauderdale, FL, says:
"Unfortunately diabetic retinopathy usually does not have any symptoms in the early stages."
Thus, it is important that people with diabetes have their eyes tested every year, follow the advice of their eye health practitioner, and make sure they keep their blood sugar under control.
Poor glucose control and access to eye health services
The researchers suggest poor control of blood glucose and inadequate access to eye health services in many parts of the world are contributing to the rising numbers of people with diabetes-related vision loss.
- Diabetic retinopathy is a leading cause of blindness in American adults
- During 2000-2010, the number of Americans with diabetic retinopathy increased 89 percent, from 4.1 million to 7.7 million
- This number is expected to nearly double to 14.6 million Americans with diabetic retinopathy by 2050.
For their investigation, the researchers carried out a meta-analysis of published population studies from 1990-2012 for the Global Burden of Disease Study 2010. A meta-analysis is where you pool data from several studies of similar design and analyze it as if it came from one large study.
The researchers extracted and pooled data on diabetic retinopathy to produce estimates of global regional trends on the condition as a cause of moderate and severe vision impairment and blindness.
They found that over the period 1990-2010, South Asia, Middle East and North Africa, and West Sub-Saharan Africa, were the regions with the highest number of people with visual impairment due to diabetic retinopathy, while East Asia, Tropical Latin America, and South Sub-Saharan Africa had the highest number of people rendered blind by the condition.
The biggest rise in the proportion of the over-50s population whose vision impairment was due to diabetic retinopathy occurred in Central, South, and Tropical Latin America, while South Sub-Saharan Africa, Southern Latin America, and Central Sub-Saharan Africa had the biggest rise in the proportion of over-50s rendered blind by the condition.
The researchers found a slight fall in visual impairment due to diabetic retinopathy occurred in South and Southeast Asia, Oceania, and East and West Sub-Saharan Africa.
'Address global epidemic of diabetes'
Lead investigator Rupert R.A. Bourne, professor and associate director of the Vision and Eye Research Unit at Anglia Ruskin University in the United Kingdom, says:
"With the alarming prevalence of vision loss due to diabetes rising more than two thirds in the last 20 years, the precipitous global epidemic of diabetes must be addressed."
He and his colleagues suggest policymakers in the regions most affected by diabetic retinopathy should develop and implement plans for preserving the vision of diabetic adults, screen for diabetic retinopathy, and improve glucose and blood pressure in diabetics.
They should also intensify efforts to prevent and treat diabetic retinopathy - for instance, by introducing laser treatments, use of intravitreal injections of steroids, and anti-VEGF (vascular endothelial growth factor) drugs.
"People diagnosed with diabetes should have a dilated eye health exam at least every year and be advised by their eye care practitioner for their personal situation. Patients should work closely with their healthcare provider to determine the best methods to control their blood sugar levels."
Prof. Janet Leasher