Dopamine and Early Retinal Dysfunction in Diabetes: Insights From a Phase 1 Study.

Abstract

Diabetes is a rapidly growing chronic disease worldwide, and one of its common complications, diabetic retinopathy (DR), is a leading cause of blindness in middle-aged people (1). Classically, DR has been identified by its microvascular phenotype on fundus examination in the eye clinic, which includes microaneurysms, retinal nerve-fiber layer infarcts, intraretinal hemorrhages, retinal exudation, and abnormal blood vessel growth (2). However, insights from the ever-growing body of literature on this blinding retinal disease have shown that DR effects the entire neurovascular unit that encompasses the intimate relationships between the neurons, glia, and vasculature of the retina (2). To this end, studies have demonstrated retinal dysfunction and alterations in retinal structure prior to the detection of the above described vascular abnormalities (3–6). Furthermore, by time the microvascular complications of DR are apparent, impairment in visual function and vision loss is typically already present (7). Therefore, being able to reliably detect retinal deficits prior to observable vascular changes may identify a window where interventions can be administered to slow or halt DR and prevent irreversible visual loss. The electroretinogram (ERG) measures the electrical activity of the retina in response to a light stimulus. ERGs require trained personnel, dilation of the pupils, placement of electrodes on the cornea, and patient cooperation to limit eye movements, limiting its practicality as a screening test in retinal disorders. The ERG response that is recorded has many different components. Oscillatory potentials (OPs) are one of …