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  • Cornea/External Disease

    Review of: Corneal nerve regeneration is affected by scar location in herpes simplex keratitis: A longitudinal in vivo confocal microscopy study

    Posarelli M, Chirapapaisan C, Muller R, et al. The Ocular Surface, April 2023

    Centrally located corneal scarring due to herpes simplex virus appears to significantly decrease corneal nerve regenerative abilities in comparison to scarring located more peripherally, according to this longitudinal study of patients with herpes simplex keratitis.

    Study design

    This is a prospective, longitudinal, case-control study. Twenty-three patients with unilateral presumed herpes simplex virus (HSV) corneal scars were divided into two groups based upon the presence of central corneal scarring (in the central 5 mm) or peripheral corneal scarring. Bilateral in vivo confocal nerve density and corneal sensation were measured during a 1-year period in comparison to 24 healthy controls.


    Corneas with central scarring showed a more severe reduction in overall corneal nerve density and corneal sensation than corneas with peripheral scarring. Significant decreases in corneal nerve density, as compared to normal controls, were also detected in the unaffected, contralateral corneas. At 1 year follow-up, eyes with central scarring also had decreased nerve regenerative abilities as compared to those with peripheral corneal scars.


    The HSV diagnosis was not confirmed by PCR, rather it was made clinically. Also, depth, density, and total area of the scars were not assessed.

    Clinical significance

    This study confirms that HSV negatively affects the cornea of both the affected and unaffected eye. Furthermore, patients with HSV-related central scars appear to be at greater risk than those with peripheral scars for the development of secondary neurotrophic corneal complications. This suggests that patients with central scars should be monitored more closely for neurotrophic keratopathy–related sequelae.

    Financial Disclosures: Dr. Seitzman discloses a financial relationship with Dompe (Consultant/Advisor).