Diabetic Retinopathy: Importance Of Early Detection For Prevention Of Eye Damage and Complications
According to the Centers for Disease Control and Prevention (CDC), about 30.3 million or 9.4% of the US population had diabetes in 2015. Diabetic retinopathy is the most common microvascular complication of diabetes mellitus and is a leading cause of preventable blindness worldwide.
Early diagnosis by clinical examination or by grading of retinal photographs is essential to prevent vision loss. Annual screening of the retina is recommended but poses a huge challenge given the current prevalence of diabetes in the United States which is expected to triple by 2050.
The risk of diabetic retinopathy increases the longer the person has diabetes. Diabetic retinopathy is divided into two broad categories: Non-proliferative diabetic retinopathy and proliferative diabetic retinopathy.
Non-proliferative diabetic retinopathy is divided into mild, moderate and severe stages. Diabetic macular edema (DME), which is defined as swelling in the area of the retina called the macula, (the area responsible for central vision) can occur at any stage of the disease. The prevalence of diabetic retinopathy in patients older than 40 years of age with diabetes exceeds 40%, with 8.5% developing vision-threatening complications, including proliferative diabetic retinopathy (PDR), severe non-proliferative diabetic retinopathy, or macular edema.
The most common cause of vision loss in diabetics is from proliferative diabetic retinopathy (PDR) and from diabetic macular edema (DME). Approximately 4% of patients with diabetes in the United States have DME.
The progression of diabetic retinopathy can be prevented or improved through control of diabetes and blood pressure for some patients, while others require treatment. The standard of therapy for DME in the mid 1980s was laser photocoagulation with focal laser to leaking blood vessels, which can reduce the risk of moderate vision loss by 50% and improve vision in approximately 30% of eyes with vision impairment.
With the advent of intravitreal anti-vascular endothelial growth factor (anti-VEGF) more than 10 years ago, this has now replaced focal laser as the standard of care for the treatment of diabetic macular edema. There are now three anti-VEGF drugs for DME including aflibercept (FDA approved), Ranimizumab (FDA approved) and Bevacizumab (prescribed “off-label”).
The standard of care for proliferative diabetic retinopathy (PDR), the other most common cause of vision loss in diabetics, has been panretinal photocoagulation (PRP). According to the Diabetic Retinopathy Study (DRS) the risk of severe vision loss due to complications of PDR reduced by half from 25% to 14% over two years.
With the advent of anti-VEGF injections, a study in 2015 concluded that treatment with ranibizumab resulted in visual acuity that was noninferior to (not worse than) PRP at two years among eyes with PDR.
Given the increasing burden of diabetes in the United States, it is imperative to get annual eye exams by a retina specialist to prevent vision loss and the devastating complications of diabetic retinopathy. It is important to be educated on the nature of the disease, the need for compliance and regular follow ups.
A discussion on the treatment options and what is to be expected in the future helps patients understand that this is a long-term commitment to their health plan.