To assess a range of measures of corneal pathology and corresponding sensory innervation patterns in blepharospasm patients. The identification of corneal pathology may open new avenues to treatment by modulating the sensory pathways of the abnormal blink reflex in blepharospasm.

20 blepharospasm patients and 20 gender and age-matched controls completed the standardized ocular surface disease index questionnaire and were examined for ocular surface disease, measured by tear osmolarity (Tearlab osmolarity system), Shirmer test, tear break-up time, National Eye Institute grading for assessment of ocular surface staining in dry eye, corneal sensitivity (Cochet-Bonnet aesthiometry) and confocal microscopy (Heidelberg Retina Tomograph II/Rostock Cornea Module).

The in-vivo confocal microscope was used to obtain 5 scans of central subbasal corneal nerves per eye. Three best quality images per eye were selected and they were analysed by a masked observer. The following nerve parameters were analysed: number of main nerve trunks, number of nerve branching, total number of nerves, nerve density, nerve tortuosity.

14 female and 6 male patients were recruited, with a median age of 64 years; control patients were matched within 3 years of age. Strikingly, a significant difference in aesthesiometry (p=0.01) was found between patients and controls. Abnormalities of nerve branching (p=0.03) in blepharospasm patients were identified with confocal microscopy.

This study demonstrates that abnormalities in corneal aesthesiometry and the morphology of the subepithelial corneal nerve plexus are features of blepharospasm. This is consistent with a growing appreciation that somatosensory abnormalities are part of the pathogenesis of dystonias.