Corneal Sub-Basal Nerve Plexus in Non-Diabetic Small Fiber Polyneuropathies and the Diagnostic Role of In Vivo Corneal Confocal Microscopy

Abstract

In vivo corneal confocal microscopy (IVCM) allows the immediate analysis of the corneal nerve quantity and morphology. This method became, an indispensable tool for the tropism examination, as it evaluates the small fiber plexus in the cornea. The IVCM provides us with direct information on the health of the sub-basal nerve plexus and indirectly on the peripheral nerve status. It is an important tool used to investigate peripheral polyneuropathies. Small-fiber neuropathy (SFN) is a group of neurological disorders characterized by neuropathic pain symptoms and autonomic complaints due to the selective involvement of thinly myelinated Aδ-fibers and unmyelinated C-fibers. Accurate diagnosis of SFN is important as it provides a basis for etiological work-up and treatment decisions. The diagnosis of SFN is sometimes challenging as the clinical picture can be difficult to interpret and standard electromyography is normal. In cases of suspected SFN, measurement of intraepidermal nerve fiber density through a skin biopsy and/or analysis of quantitative sensory testing can enable diagnosis. The purpose of the present review is to summarize the current knowledge about corneal nerves in different SFN. Specifically, we explore the correlation between nerve density and morphology and type of SFN, disease duration, and follow-up. We will discuss the relationship between cataracts and refractive surgery and iatrogenic dry eye disease. Furthermore, these new paradigms in SFN present an opportunity for neurologists and clinical specialists in the diagnosis and monitoring the peripheral small fiber polyneuropathies.

Objektive Analyse von Hornhautnerven und dendritischen Zellen

“…Seit der klinischen Verbreitung der intravitalen Konfokalmikroskopie (IVCM) wurden Veränderungen von Hornhautnerven und DCs in Bezug auf zahlreiche Erkrankungen untersucht, wie z. B. beim trockenen Auge 13 , 14 , 15 , nach (refraktiver) Hornhautchirurgie 16 , 17 , 18 , 19 , beim Kontaktlinsentragen 20 , 21 , bei Diabetes 22 , 23 , 24 , Polyneuropathien 25 , 26 , Migräne 27 , Small-Fiber-Neuropathie 28 , 29 , neuropathischen Schmerzen 22 , 30 , rheumatoider Arthritis 31 und nach Chemotherapien 32 .…”

“…Changes in corneal nerves and DCs have been studied with regard to many diseases such as dry eye 13 , 14 , 15 , eye condition after (refractive) corneal surgery 16 , 17 , 18 , 19 , contact lens wear 20 , 21 , diabetes 22 , 23 , 24 , polyneuropathies 25 , 26 , migraine 27 , small-fibre neuropathy 28 , 29 , neuropathic pain 22 , 30 , rheumatoid arthritis 31 , and chemotherapy 32 ever since intravital confocal microscopy became commonplace in clinical practice.…”