Current Strategies and Challenges in the Management of Diabetic Retinopathy*

The retina is a vascularized neural structure that is composed of blood vessels, neurons, glial cells, and microglia. Diabetes produces a number of well-known alterations to the vascular structure of the eye, but also causes significant retinal neurodegeneration. The response of the retina to visual stimulation has long been evaluated using the electroretinogram. This method assesses the summed electrical activity across the entire retina, and may fail to detect small regions of retinal dysfunction. More recently, retinal dysfunction in diabetes has been evaluated using the multifocal electroretinogram (MF-ERG), which simultaneously records the electrical activity of dozens of discrete retinal regions. The MF-ERG is able to detect subtle retinal dysfunction in eyes that lack clinically evident retinopathy, and to identify retinal regions that subsequently develop significant retinopathy. Optical coherence tomography, which measures small differences in retinal thickness, is also increasingly used to evaluate retinal changes in diabetic macular edema (DME). The incidence of DME is significantly affected by a number of systemic factors, including glycemic control, hypertension, congestive heart failure, kidney failure, hypoalbuminuria, and anemia. Recent studies have identified numerous retinal growth factors and cytokines that may influence the development of diabetic retinopathy. Understanding the mechanisms of retinal neurovascular dysfunction and edema formation in diabetes should help to improve patient care by ensuring that modifiable risk factors are adequately addressed, and may also lead to the development of new and more effective therapies for diabetic retinopathy and DME. (Adv Stud Ophthalmol. 2005;2(1):14-19)