Updates on Diabetic Retinopathy from the ADA
By Lisa Foster-McNulty, MSN, RN, CDE
What is Diabetic Retinopathy?
Diabetic Retinopathy (DR) is a complication of diabetes (both Type 1 and Type 2) that can lead to complete loss of vision if it is not treated. From most mild to most advanced, the four stages of DR are mild/moderate/severe non-proliferative DR, and proliferative DR (PDR).
Chronic high blood glucose (BG) levels can lead to damaged blood vessels in the eye, so the rate of DR occurring is related to both the level of BG control and the length of time a person has been living with diabetes. Other conditions which are risk factors for DR include hyperglycemia, diabetic kidney disease, high blood pressure (BP), and elevated cholesterol levels. In people who have Type 2 diabetes, research shows that reducing elevated BP levels will diminish the progression of retinopathy, although strict targets for BP such as a systolic (top number) of 120 vs 140 have not been shown to confer any extra advantage. One study indicated that progression of retinopathy decreased in patients with elevated cholesterol levels when fenofibrate was added, especially if the DR was non-proliferative at baseline. Other studies suggest that with poor glycemic control at conception, pregnant Type 1 patients can worsen their retinopathy.
Along with eye exams being scheduled at appropriate intervals, the risk of vision loss from DR can be minimized by optimizing control of BG, BP, and cholesterol. However, many people with diabetes do develop diabetic macular edema (swelling of the macula in the eye), or proliferative eye changes which necessitate treatment. Intensive treatment of diabetes with the goal of keeping BG levels close to normal may prevent or delay the onset of DR, according to the results of large research studies.
How to Diagnose and Treat Diabetic Retinopathy
With its most recent clinical standards for medical care, ADA recommendations for diagnosing and treating DR have improved significantly since 2002. Newer therapies for treating diabetes have helped patients to improve blood glucose levels, and the statement helps providers and patients to better assist in the diagnosis and treatment of DR. Additionally, it gives us a chance to improve glycemic control and prevent or delay the onset of this complication.
A meta-analysis study comprised of 35 individual studies was conducted from 1980-2008. Throughout the world, the prevalence is predicted to be 35.4% for DR and 7.5% for PDR in developed countries. DR is the major cause of new blindness in 20 to 74 year olds; eye disorders like cataracts and glaucoma are often found in the diabetes population.
In the guidelines, the recommendation is that patients with diabetes should be screened by an ophthalmologist or optometrist. Type 1 patients are screened within five years after diagnosis, and Type 2 patients are screened at diagnosis. If no retinopathy is noted on exam, the next eye exam can be done in two years. Once retinopathy is detected, follow up exams should be done at least yearly, but can be done more often if retinopathy is progressing. Women with diabetes who are planning to become pregnant, or those with pre-existing diabetes and who are already pregnant, should have an eye exam prior to conception or in the first trimester.
Screening for DR is cost-effective. Laser treatment is standard for DR. Telemedicine even has a role in identifying and managing DR, because it is effective when there is a low ratio of providers to patients. It’s also effective when distance precludes a patient from being able to reach a provider, or when a patient has no other option for being screened. Additionally, the guidelines consider anti-VEGF therapy, which is a more recent development in the treatment of retinopathy, because the cost-effectiveness is good as compared to laser monotherapy for diabetic macular edema (swelling). However, more study is needed to learn whether it is cost-effective to use anti-VEGF as a first-line treatment for PDR. One more point–retinopathy is not a reason to withhold aspirin therapy for heart protection; studies indicate that its use does not cause an increased risk of retinal bleeding.
If you have diabetes, make sure you get your dilated eye exams done at the recommended intervals. Early detection allows for treatment and preservation of vision. Don’t be lulled into thinking that everything is okay because you haven’t noticed any changes to your vision. When you experience changes, the damage is already done–so take a preventative approach!