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

Context: Retinal microperimetry (MPR) is a non-invasive method that measures retinal light sensitivity (RS) and gaze fixation stability (GFS). MPR has been described as a marker of cognitive impairment in people with Type 2 diabetes, but it has never been assessed in people with Type 1 diabetes (T1D). Our group described subclinical cognitive alterations, structural brain differences, and increased levels of light chain neurofilament (NfL) in people with T1D and impaired awareness of hypoglycaemia.

Objective: To measure RS and GFS using MPR in individuals with T1D and evaluate its correlation with neuropsychological assessment, plasma NfL levels and CGM-derived glucometric parameters.

Secondary Objectives: to evaluate the possible differences of RS and GFS in people with T1D depending on hypoglycaemia awareness.

Design, Setting And Participants: Pilot observational study, people with T1D without clinical cognitive impairment, moderate-severe retinopathy or glaucoma. MPR was performed with MAIA3.

Results: A total of 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 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). An inverse correlation between GFS and time below range was found. No correlation was found with NfL.

Conclusion: This first exploratory study in people with T1D supports the potential utility of MPR as a screening tool for subclinical neurocognitive alterations in this population.