Structural and metabolic retinal changes associated with mild cognitive impairment in type 2 diabetes

Abstract

Type 2 diabetes is associated with cognitive impairment and a twofold increased risk of dementia compared with age-matched individuals without diabetes. Given that the eye and the brain share similar embryologic origin and an-atomical features, the retina offers a unique window to the brain. In this study, we wanted to determine whether there was a difference in retinal imaging–based neuronal and vascular markers in individuals with type 2 diabetes with or without mild cognitive impairment (MCI). We included 134 persons with type 2 diabetes. Based on neuropsy-chological tests, the prevalence of MCI was 28%. We performed seven-field color fundus photos, optical coherence tomography (OCT), OCT-angiography (OCT-A), and retinal oximetry to analyze retinal markers. In a mul-tivariable cluster analysis, persons with MCI had a significantly thinner macular retinal nerve fiber layer and macular ganglion cell layer, and less venular oxygen saturation in the nasal quadrant compared with those without MCI. There were no differences in retinal vessel density, fractal dimension, width, tortuosity, or OCT-A markers. People with type 2 diabetes and MCI demon-strate alterations in retinal structure and metabolism, suggesting noninvasive retinal markers may be useful to detect people with type 2 diabetes at risk for cognitive dysfunction.