April 19, 2021Ophthalmology
An estimated 30 million Americans have diabetes, which can cause blood vessel abnormalities, including the growth of new blood vessels in the eye. In the early stages of diabetic retinopathy, called non-proliferative diabetic retinopathy, changes in the eye's blood vessels are visible to clinicians but generally do not affect sight. In the advanced stages, people can develop proliferative diabetic retinopathy, where retinal blood vessels grow abnormally, and/or diabetic macular edema, where fluid leaks out of the retinal blood vessels. Both can lead to vision loss and blindness. Treatment, such as with anti-VEGF drugs, can slow or prevent vision loss in people with proliferative diabetic retinopathy or diabetic macular edema, if treatment occurs promptly.
According to an article published in JAMA Ophthalmology (30 March 2021), a clinical trial from the Network has demonstrated that early treatment with anti-vascular endothelial growth factor (VEGF) injections slowed diabetic retinopathy. However, two years into the four-year study, the early treatment's effect on vision - including changes in visual acuity and vision loss - was similar to standard treatment, which usually begins only after the onset of late disease.
In this study, subjects with non-proliferative diabetic retinopathy were randomly assigned at baseline to receive either injections of Eylea (aflibercept) or a sham injection. They were examined at one, two, and four months, and then every four months for two years, receiving Eylea or sham injection at each visit. The authors tracked the subject's visual acuity and the severity of their diabetic retinopathy. If disease progressed, regardless of whether they were in the treatment or sham group, participants were given Eylea more frequently as is given in standard practice. If their condition did not improve with additional anti-VEGF treatment, participants could be given treatments such as laser photocoagulation or surgery if necessary.
The study included 328 participants (399 eyes). Results showed that after two years of treatment, the rate of proliferative diabetic retinopathy development was 33% in the control group, compared with 14% in the treatment group. Likewise, the rate of development of diabetic macular edema affecting vision was 15% in the control group, compared with 4% in the treatment group. However, loss of visual acuity was essentially the same between the two groups at two years, suggesting that standard treatment at the appearance of proliferative diabetic retinopathy or diabetic macular edema affecting vision is sufficient to prevent further vision loss at this time point.