Modifications of the Subepithelial Nerve Plexus in Essential Blepharospasm: A Comparative Study With Gougerot-Sjögren Patients and Normal Subjects. An Evaluation With in vivo Confocal Microscope

Abstract

Purpose: : The patients affected by essential blepharospasm (EBS) complain about very invalidating, chronic ocular pains, more important than the one expressed by the patients affected by illness of Gougerot-Sjögren (GS). We compared the aspect of the cornea observed with the in vivo confocal microscope among 15 patients affected by EBS, 10 patients affected by GS and 8 normal patients. The goal of this survey is to specify the aspect of the subepithelial nerve plexus in these three populations of patients.

Methods: : The patients were examined with the in vivo confocal microscope: the Heidelberg Retina Tomograph II / Rodstock Cornea Module (Heidelberg Engeneering GmbH, Germany) covering an area of 400µm by 400µm with transverse optical resolution of 2µm. Informed consents was obtained from all subjects.

Results: : Pathological subepithelial nerve plexus were founded in EBS as sprouting nerve, thick and spiny nerve, hair-pine nerve, snowball-nerve, edelweiss-shaped nerve, pear-shaped bulging nerve, and dendritic bulging. These aspects are more severe in EBS than in GS and are not encountered in normal patients.

Conclusions: : In vivo confocal microscopy is a reliable and efficient examination of the corneal subepithelial nerve plexus which allow us to understand the eye-surface pain of EBS patients. These new pathologic findings in the subepithelial nerve plexus in EBS can explain the pain and photophobia encountered in EBS, which is more important than in GS although the dry eye syndrome is similar.These pathological corneal nerve observations can point out that EBS is more than an orbicularis dystonia.

Keywords: cornea: tears/tear film/dry eye • pathobiology • nerve fiber layer