Corneal Confocal Microscopy Shows Progressive Reduction in Corneal Nerve Fiber Length over a 2 Year Time Period in Children with Type 1 Diabetes
Stephanie A. Dotchin, MD; Heidi T. Virtanen, MSc; Kenneth G. Romanchuk, MD; Daniele Pacaud, MD; Alberto Nettel-Aguirre, PhD, PStat; Lisa M. Lagrou, MD; Jean K. Mah, MD; Rayaz A. Malik, MBChB
University of Calgary
Calgary, Alberta, Canada
Introduction: Corneal confocal microscopy (CCM) of the corneal sub-basal nerve fiber layer has been suggested as a surrogate marker for peripheral diabetic neuropathy. We report findings of corneal nerve fiber layer length (CNFL) at baseline and 2 years(yrs) later in children with type 1 diabetes mellitus (T1DM) of at least 5yrs duration.
Methods: 71 children with T1DM with mean(SD) age 14.7(2.3)yrs, T1DM duration 9.1(2.7)yrs; and 23 healthy controls aged 12.6(0.6)yrs underwent baseline and 2yr follow-up CCM examination. CNFL was quantified using automated image analysis and compared via independent t-tests and Repeated Measures ANOVA to explore change over 2yrs; and McNemar’s Test to compare the proportion of individuals with abnormal CNFL over 2yrs.
Results: Mean CNFL was significantly lower in children with T1DM compared to controls at baseline (p=0.02) and at 2yrs (p=0.001). Point estimates of mean differences in CNFL indicated lower 2yr measures in T1DM and higher 2yr measures in controls, but this was not statistically significant (p=0.054). The proportion of participants with an abnormal CNFL (cut-off established from healthy controls) changed from 7 to 17 in T1DM (p=0.013) and from 0 to 2 in controls (p=0.500), over 2yrs.
Discussion: Children with T1DM of at least 5yrs duration have a lower CNFL compared to control subjects at baseline and 2yrs later; and after 2yrs, the proportion of children with an abnormal CNFL was significantly higher in T1DM, with no significant change in controls.
Conclusion: These findings suggest early and progressive corneal nerve loss over a relatively short period of time in children with T1DM.
References: Pop-Busui R, Boulton AJ, Feldman EL, et al. Diabetic Neuropathy: A Position Statement by the American Diabetes Association. Diabetes care 2017;40:136-54.
Ahmed A, Bril V, Orszag A, et al. Detection of diabetic sensorimotor polyneuropathy by corneal confocal microscopy in type 1 diabetes: a concurrent validity study. Diabetes care 2012;35:821-8.
Chen X, Graham J, Dabbah MA, Petropoulos IN, Tavakoli M, Malik RA. An Automatic Tool for Quantification of Nerve Fibers in Corneal Confocal Microscopy Images. IEEE transactions on bio-medical engineering 2017;64:786-94.