Corneal Confocal Microscopy: a Surrogate Endpoint for Neurodegeneration in Clinical Trials


Corneal Confocal Microscopy in ISFN

Corneal confocal microscopy (CCM) has been shown to be an objective, non-invasive diagnostic tool for evaluation of small nerve fiber loss, especially in patients with diabetes mellitus. Moreover, it is a repeatable test that can be used as surrogate endpoint for evaluating therapeutic efficacy in clinical trials. The diagnostic value of CCM in small fiber neuropathy (SFN) is not established yet. According to international criteria, the diagnosis small fiber neuropathy (SFN) is based on clinical symptoms in combination with a reduced intraepidermal nerve fiber density (IENFD) in skin biopsy and/or abnormal temperature threshold testing (TTT). The sensitivity of skin biopsy is moderate. Furthermore, TTT lacks specificity and may be influenced by malingering or other nonorganic factors. We have studies the applicability of CCM in patients with SFN, and the value of CCM as an additional diagnostic tool in SFN. Corneal nerve fiber density (CNFD), branch density (CNBD), fiber length (CNFL), and the tortuosity coefficient (CNFT) were determined in all participants. Correlation studies were performed to evaluate the correlation among CCM parameters and IENFD and TTT. The final results of this study will be presented.