Possibilities of early diagnosis of diabetic polyneuropathy based on the study of corneal nerve fibers

    Abstract

    Possibilities of early diagnosis of diabetic polyneuropathy based on the study of corneal nerve fibers

    S.E. Avetisov, N.A. Chernenkova, Z.V. Surnina, L.T. Аkhmedzhanova, A.S. Fokina, I.A. Strokov

    Federal State Scientific Institution Research Institute of Eye Diseases, Moscow
I.M. Sechenov First Moscow State Medical University, Moscow

    A feature of the method of laser confocal microscopy (CCM) is the possibility of in vivo non-invasive imaging of the thin corneal nerve fibers (CNF).

    Рurpose. To conduct a comparative analysis of the results of laser confocal microscopy and known neurological instrumental techniques (electroneuromyography, quantitative sensory testing); to evaluate the capabilities of the automated algorithm for the analysis of corneal nerves in the early diagnosis of DPN.

    Мaterial and methods. We examined 46 patients (85 eyes) with type 1 diabetes, where 24 patients with subclinical, 22 with the clinical stage of DPN, 50 patients (87 eyes) with type 2 diabetes, where 27 patients had subclinical, 23 clinical stage DPN, the control group consisted of 34 healthy volunteers (68 eyes). All patients underwent standard ophthalmic examination methods, laser confocal microscopy with nerve tortuosity assessment (calculation of anisotropy coefficients, K_ΔL and nerve orientation symmetry, K_sym) and interocular asymmetry, electroneuromyography (ENMG), quantitative sensory testing.

    Results. Reliable correlations of the anisotropy coefficient (K_ΔL) with the parameters of the amplitude of the M-response, RL and SRV of the peroneal nerve (r=0.486, p≤ 0.03; r= -0.469, p≤ 0, were revealed in type 1 diabetes and the subclinical stage of DPN). 03; r=0.649, p≤ 0.002, respectively), M-response of the tibial nerve (r=0.497, p≤ 0.02); symmetry coefficient (K_sym) – with the values of the amplitude of the M-response (r=0.622, p≤ 0.03), SRV of the calf nerve (r=0.482, p≤ 0.03). K_sym values correlated with the indices of thermal and cold sensitivity according to KST (r=-0.678, p≤ 0.001; r=-0.475, p≤ 0.034). In type 2 diabetes mellitus and subclinical DPN, significant correlation dependencies were observed between the anisotropy coefficient (K_ΔL) and the radial fibrous nerve (r=0.51, p≤ 0.03), and M was the response of the tibial nerve (r=0.524, p≤ 0.025); correlation of the symmetry coefficient (K_sym) with the C-response index of the gastrocnemius nerve (r=0.647, p≤ 0.004) and the threshold for cold perception (r=-0.561, p≤ 0.015).

    Сonclusion. Laser confocal microscopy data correlates with ENMG – / CTF – parameters of peripheral nerves. Laser confocal microscopy can help detect changes in nerve fibers in the early (subclinical) stage of DPN.

    Key words: laser confocal microscopy, anisotropy coefficients, symmetry of the orientation of the corneal nerves, diabetes mellitus, diabetic polyneuropathy.