Clinical Pearls & Morning Reports
Published April 22, 2020
Over the past decade, advances in technology such as retinal imaging and the development of new therapies have dramatically improved the evaluation, treatment, and visual outcomes of patients with diabetic retinopathy. Nonetheless, diabetic macular edema and proliferative diabetic retinopathy remain the leading causes of both moderate and severe vision loss in most developed countries. Read the NEJM Review Article here.
Q: What is the interval in most patients between a diagnosis of diabetes and the development of retinopathy?
A: In most patients, retinopathy develops 10 to 15 years after diabetes has been diagnosed. With the increasing prevalence of diabetes, more people are at risk for retinopathy, and greater resources are required to identify and treat this condition.
Q: Have rates of proliferative diabetic retinopathy increased or decreased in the United States in recent decades?
A: Although the global prevalence of diabetes is increasing, recent advances in care are resulting in reduced rates of vision loss in populations that are screened appropriately and given timely access to medical advances. Rates of proliferative diabetic retinopathy and severe vision loss have declined over the past four decades in the United States and other developed countries.
A: Because of its greater efficacy in reducing diabetic macular edema and improving vision, treatment with intravitreal antivascular endothelial growth factor (VEGF) injection has generally replaced macular laser therapy worldwide as the initial standard treatment for eyes with visual-acuity loss from diabetic macular edema. Glucocorticoids such as sustained-release fluocinolone acetonide and dexamethasone implants were shown to reduce retinal thickening and to improve vision; however, intravitreal treatment with glucocorticoids results in an increased risk of cataracts requiring surgery and can induce increased intraocular pressure and glaucoma. Given the variable efficacy of glucocorticoids and concern about ocular safety, anti-VEGF therapy has become the principal treatment for diabetic macular edema. Most eyes with diabetic macular edema respond to anti-VEGF therapy with some degree of anatomical improvement, visual improvement, or both, but in nearly 40% of eyes, complete resolution of diabetic macular edema is not achieved.
A: Since the 1970s, proliferative diabetic retinopathy has been treated with panretinal laser photocoagulation, which is effective in preserving central vision but can be associated with an exacerbation of macular edema, loss of visual field, impaired night vision, and loss of contrast sensitivity. More recently, two randomized trials provided evidence that anti-VEGF therapy can be used successfully as an alternative to panretinal laser photocoagulation for the treatment of proliferative diabetic retinopathy. However, there are barriers to large-scale adoption of anti-VEGF treatment for proliferative diabetic retinopathy. Frequent anti-VEGF injections are required, and adherence to frequent follow-up visits and treatments is challenging for some patients. Frequent injections of anti-VEGF agents, particularly aflibercept or ranibizumab, are more costly than panretinal laser photocoagulation, even if laser photocoagulation is administered more than once, as it was, on average, in the trials described above. Treatment efficacy, the likelihood of adherence to the regimen, cost, and treatment burden all need to be considered in selecting a therapeutic approach for a patient with proliferative diabetic retinopathy.