Small nerve fiber loss and damage, a neuropathy of the sensory and autonomic nervous systems, often appears after chemotherapy or develops following a number of genetic, degenerative, or metabolic diseases, with diabetes being its primary cause. Because of the different etiologies of small fiber neuropathy (SFN) and the variety of organs that can be affected, the neurological symptoms developed by patients with SFN are highly variable and may include intense pain and several autonomic symptoms. Skin biopsy for estimating intraepidermal nerve-fiber density is one objective approach to evaluate the level of peripheral nerve damage. This procedure is inconvenient because it is invasive and because the results are difficult to interpret owing to the morphological complexity of the sensory and autonomic innervation of the skin.
Tervo T, Holopainen J, Belmonte C. Confocal Microscopy of Corneal Nerves—a Limited but Still Useful Technique to Evaluate Peripheral Neuropathies. JAMA Ophthalmol. 2016;134(9):990-991. doi:10.1001/jamaophthalmol.2016.2178