Could An Emerging Adjunct Measure Of Diabetic Neuropathy Be Found In The Eyes?

A recent publication in Nature Scientific Reports exhibits important work from our longtime SALSA-migo, Rayaz Malik, MBChB, PhD, and team.¹ In the study, which involved 19 patients with diabetes and 19 healthy control subjects, the authors assessed the presence of signs and symptoms of neuropathy, quantitative sensory testing, autonomic nerve function, neurophysiology, intraepidermal nerve (fiber) density (IENFD) and corneal confocal microscopy (CCM) over a mean follow-up of 6.5 years. 

The study results showed worsening of diabetic neuropathy across a range of neuropathy measures, especially corneal confocal microscopy. This was independent of the additional findings in the cohort of an improvement in HbA1c and low-density lipoprotein cholesterol (LDL-C). The authors of this study note that corneal confocal microscopy is a rapid, non-invasive adjunct measure of diabetic neuropathy.

Microvascular complications of diabetes affect the organs at the end of the vascular tree in a similar fashion, whether this involves matrices in the kidney, the eye or the nerve. That is why taking a step back and figuring out novel methods for rapidly assessing associated risk can be so valuable.

Normal sensation to a 10 gram monofilament alone does not completely rule out diabetic peripheral neuropathy. I questioned the adequacy of this tool (by itself) 21 years ago and that critique is even more valuable today.² Having something that allows for consistent assessment across time might be a great adjunct. 

The findings in this study by Malik and coworkers highlight a potential opportunity to collaborate with ophthalmologic colleagues, however, in creating a comprehensive “eye to toe” peripheral neurologic assessment for patients with diabetes.

Dr. Armstrong is Professor of Surgery at the Keck School of Medicine at the University of Southern California. He is the Director of the Southwestern Academic Limb Salvage Alliance (SALSA). 

Editor’s note: This blog originally appeared at:  https://diabeticfootonline.com/2021/01/24/corneal-confocal-microscopy-identifies-small-fibre-damage-and-progression-of-diabetic-neuropathy-scireports-wcmqatar/ . It is adapted with permission from the author.

References

1. Dhage S, Ferdousi M, Adam S, et al. Corneal confocal microscopy identifies small fibre damage and progression of diabetic neuropathy. Sci Reports. 2021;11(1):1859. Available at: https://www.nature.com/articles/s41598-021-81302-8 . Published January 21, 2021. Accessed February 1, 2021.

2. Armstrong DG. The 10-g monofilament: the diagnostic divining rod for the diabetic foot? Diabetes Care. 2000;23(7):887.