As long as they remain asymptomatic, patients with type 2 diabetes can easily forget about the devastating systemic consequences of the disease. And this comfort level may be their downfall, because diabetic retinopathy (DR) is a sneaky, sight-stealing thief that can burst onto the scene with little or no advance warning.
DR does not develop in every patient with diabetes. However, the estimated prevalence of DR in the United States from 2005 to 2008 was a substantial 28.5% in diabetic adults, and the prevalence of vision-threatening DR was 4.4%, said Mary Elizabeth Hartnett, MD, professor, Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City.
One way pharmacists can promote patient education is by reminding patients of the inherent visual risks associated with diabetes and emphasizing the importance of regular ocular evaluations to rule out the presence of DR or to facilitate early intervention to prevent progression.
How diabetes may affect vision
Diabetes affects the retinal vasculature and the existing normal retinal blood vessels in several ways.
Sometimes diabetes causes retinal capillary damage and leakiness in the macula and leads to retinal swelling, known as macular edema, which can reduce central vision.
Other times the retinal capillaries are damaged outside the macula, and the retina is starved for oxygen and nutrients. This can lead to release of substances that promote blood vessel growth into the vitreous.
In both cases, certain growth factors, such as vascular endothelial growth factor (VEGF), can be involved, Hartnett said.