In patients with diabetes, neuroretinal dysfunction that can be evaluated using electroretinogram parameters seems to progress even in patients who do not have diabetic retinopathy. These changes are associated with the progression of diabetic polyneuropathy (DPN), according to study results published in the Journal of Diabetes Investigation. The research also suggests that electroretinogram parameters taken using a hand-held device successfully predict DPN severity. 

Although it is known that DPN develops in the early stages of diabetes, no common diagnostic protocol is currently available. A team of researchers in Japan conducted an investigation in which they assessed the correlation between neuroretinal dysfunction and progression of DPN to confirm whether flicker electroretinogram using a hand-held device could detect early peripheral nervous system dysfunction in patients with diabetes. 

A total of 184 patients were included in the study; 119 patients were men and 164 patients had type 2 diabetes. Using the International Clinical Classification System, 15.8% of patients had nonproliferative diabetic retinopathy and 14.1% of patients had proliferative diabetic retinopathy


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The investigators characterized the correspondence of electroretinogram data to the stages of DPN diagnosed using Baba’s classification on the severity of DPN (BC) to examine whether electroretinography assists in DPN diagnosis. Results of a multiple regression analysis suggested that moderate to severe DPN was effectively diagnosed (area under the receiver operating characteristic curve 0.692, sensitivity 56.5%, specificity 78.3%, positive predictive value 70.6%, negative predictive value 66.1%, positive likelihood ratio 2.60, negative likelihood ratio 0.56). 

Among patients without apparent diabetic retinopathy, there was a significant association between the implicit time and amplitude of electroretinogram and parameters of vascular dysfunction such as brachial-ankle pulse wave velocity and intima-media thickness. 

“The electroretinogram data might reflect the neural and vascular impairments of the retina in patients with diabetes,” according to the researchers. “Although DPN and neuroretinal dysfunction might have similar neuropathological backgrounds, further investigation should be carried out to clarify the relationship in the future.”

Reference 

Kawai M, Himeno T, Shibata Y, et al. Neuroretinal dysfunction revealed by a flicker electroretinogram correlated with peripheral nerve dysfunction and parameters of atherosclerosis in patients with diabetes. J Diabetes Investig. 2021;12(7):1236-1243. doi:10.1111/jdi.13465