Exploring novel features in the corneal nerve plexus in a healthy population: globular cells and microneuromas

Purpose : Nerve fibres and inflammatory cells in the corneal sub-basal nerve plexus have been well characterised in both ocular disease and peripheral neuropathy using in-vivo corneal confocal microscopy (IVCM). Other recently described features, globular cells (GC) and microneuromas (enlarged nerve terminal sprouts) have been reported to have a strong association with certain diseases, however, little is known about these features in healthy individuals, and hence, their future diagnostic utility. This study, therefore, set out to establish the profile of these features in a healthy population. Methods : IVCM images from 119 healthy participants (60 females, 59 males), aged 17 to 80 years (mean: 48 ± 16 years) from the combined control cohorts of two different studies were analysed. Five to eight images from the central cornea and inferior whorl (IW) were analysed for number of microneuromas, globular and dendritic (mature and immature) cell densities (DCD), corneal nerve fibre density (CNFD), branch density (CNBD), fibre length (CNFL), and total branch density (CTBD). Associations between and within the nerve and inflammatory features and age and gender were determined using appropriate non-parametric statistics. Results : Microneuromas and GCs were present in 35 and 31% of individuals respectively. The number of microneuromas at central cornea and IW were inversely associated with age (rho=-0.203, p=0.028; rho=-0.195, p=0.034), and mature and immature DCD both at central (rho=-0.272, p=0.003; rho=-0.360, p