Professor Tien Yin Wong, an ophthalmologist and 10GA Speaker, writes about diabetic retinopathy
How significant is the problem of diabetic retinopathy (DR) on a global scale? We know that DR is a specific microvascular complication of diabetes, and for a long time, it has been the leading cause of blindness among working adult people in the US and the developed world. Over the past decade, there have been some major developments in our understanding of how common DR is in the population, which communities are most affected, what are the risk factors, and what are the trends in the disease pattern.
First, there is clear evidence of a global increase in the prevalence of diabetes, and the relative increase is most prominent in developing countries, which are least likely to be ready to deal with this major chronic disease. The good news is that there is a decline in the incidence of blindness due to DR, particularly in US, UK and developed countries, which means it is possible, with effort, to reduce the impact of DR on blindness.
Second, there is a change in disease pattern.In the past the most advanced form of DR, known as proliferative retinopathy (PDR), was the most common cause of blindness.In many countries now, vision loss is increasingly seen in people with “milder” disease severity but the pathology affects the central part of the retina. This “milder” disease is called diabetic macular edema (DME), which in many communities is now the most common cause of vision impairment. DME is now known to affect around 6.8% of the diabetic population.
Third, there is concern that despite the significant increase in public education, DR awareness in the community remains patchy and low in most populations. In some surveys, around 80-90% of people with diabetes are not aware of the need for regular screening and eye checks.
Fourth, studies suggest that the major risk factor of DR, hyperglycemia, remains the most consistent risk factor for DR in type 1 diabetes across different studies and populations. In contrast, blood pressure is an important risk factor for DR in type 2 diabetes, while the relationship of dyslipidemia and DR remains unclear, with inconsistent results from different studies and trials.
Finally, there is evidence that photographic screening of DR using tele-ophthalmology platforms is increasingly recognized as being feasible and cost-effective, but DR screening and prevention in low-resource settings cannot follow models developed in high-resource countries and requires different strategies.