Retinal Microperimetry as a Novel Tool for Early Detection of Cognitive Dysfunction and Brain Damage in Type 1 Diabetes: A Pilot Study

Abstract

Context: Retinal microperimetry (MPR) is a non-invasive method that measures retinal light sensitivity and gaze fixation stability (GFS). MPR has been described as an early marker of cognitive impairment in people with type 2 diabetes. Our group described subclinical cognitive alterations, structural brain differences, and increased levels of light chain neurofilament (NfL) in people with type 1 diabetes (T1D) and impaired awareness of hypoglycemia. The utility of MPR has not been described in T1D. Objective: to measure RS and GFS using MPR in individuals with T1D and evaluate possible differences depending on hypoglycemia awareness (IAH vs NAH). Secondary objectives: to perform a secondary analysis of correlation between MPR findings with neuropsychological assessment, plasma NfL levels, structural GM, and WM changes, and CGM-derived glucometric parameters, independently of hypoglycemia awareness. Design, setting and participants: Pilot observational study, adult people with type 1 diabetes without cognitive impairment, moderate-severe retinopathy, or glaucoma. MPR was performed with MAIA3. Results: 30 subjects were studied: 40% women, age 58 ± 11 years; T1D duration 31 ± 9 years, mild retinopathy 33%. RS was 27.5 dB (26.1–28.3) and GFS 97.6% (93.5–99.5%). We found a significant correlation between RS and memory alteration tests (p = 0.016) and between GFS and a composite of attention and executive neuropsychological tests (p = 0.025); between RS and insular cortical thickness (p = 0.04); RS and the right hippocampal volume (p = 0.02); and between GFS and the fractional anisotropy of thalamic radiations (p = 0.04). An inverse correlation between GFS and time below range was found. No correlation was found with NfL. Conclusion: Our exploratory study supports the potential utility of MPR as a screening tool for neurocognitive alterations and incipient structural brain damage in people with T1D.