Bilateral Corneal Nerve Regeneration in Herpes Simplex Virus Keratitis is influenced by the Location of Corneal Scarring

Abstract

Purpose : Herpes simplex virus (HSV) can result in corneal scars in different locations. However, it remains to be seen if the location of the scar has an effect on the recovery of neurotrophic keratopathy. This study aimed to evaluate the effect of HSV corneal scar location on bilateral corneal nerve regeneration and alteration in corneal sensation.

Methods : This prospective, longitudinal, controlled, single-center study included 39 patients with unilateral central HSV scar (CS; n=21) or peripheral HSV scar (PS; n=18) and 24 normal age-matched reference controls. Laser in vivo confocal microscopy (IVCM) with the Heidelberg Retinal Tomograph 3/Rostock Cornea Module and Cochet-Bonnet esthesiometry were performed centrally and peripherally at baseline and at 1-year follow-up. Two masked observers evaluated corneal nerve density using NeuronJ. Variables were analyzed with ANOVA.

Results : In affected eyes patients had significantly decreased subbasal nerve density, regardless of scar location, in both central (CS: 8.09±1.30; PS: 10.34±1.48mm/mm²) and peripheral cornea (CS: 5.15±0.62; PS: 4.22±0.77mm/mm²) at baseline, relative to controls (central: 22.60±0.77; peripheral: 9.91±0.49mm/mm², p<0.001). Significant nerve regeneration was observed only in the central cornea of patients with PS (16.39±2.39mm/mm², p=0.007) at 1-year follow-up. In contralateral eyes, significant nerve decrease was found in the central cornea of patients with CS (16.88±1.27mm/mm², p<0.002) and in the peripheral cornea mirroring the scar area of the affected eye in patients with PS (7.20±0.87mm/mm², p<0.05) at baseline. However, there was no significant corneal nerve regeneration in central or peripheral contralateral corneas of patients with CS and PS at 1-year follow-up compared to baseline (p>0.05). There was a positive correlation between corneal nerve density and sensation in both central (R=0.53, p<0.0001) and peripheral cornea (R=0.27, p=0.0004).

Conclusions : The location of HSV scars is related to bilateral nerve decrease as shown by IVCM. There is differential central corneal nerve regeneration in patients with HSV keratitis, dependent upon the location of the focal corneal scar. Corneal sensation had a positive correlation with corneal nerve density.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.