Difficulties Imaging Herpes Simplex Keratitis With Fluorescein Isothiocynate-Labeled Anti-HSV-1 Antibodies in an Ex Vivo Model

Aim: The aim of this study was to attempt to visualize herpes simplex keratitis in an ex vivo model using currently available ophthalmological equipment and anti-herpes simplex virus I (HSV-1) fluorescein isothiocynate-labeled antibody. Methods: Sixteen donor human corneas were included in this study. Eight corneas were infected with HSV-1, whereas 8 remained uninfected. Abrasions were made on 2 infected and 2 uninfected corneas to assess a possible nonspecific absorption of antibodies in the sites of corneal epithelial defects. Corneas were examined before and after antibody application using a slit lamp, the fluorescein enhancing filter settings of fundus camera, and Confoscan 3. All corneas were further imaged using multiphoton laser confocal microscopy. Results: Before anti-HSV-1 antibody application, no fluorescence was detected in donor corneas with the blue light of the slit lamp and fundus camera at fluorescein enhancing filter settings. Examination with the fundus camera after antibody application detected increased background fluorescence in all the corneas with more highlighted areas of epithelial defects in abraded infected and uninfected corneas. Confoscan 3 did not show a significant difference between the appearances of HSV-1-infected and control corneas with and without application of the antibody. However, specific staining was confirmed by multiphoton laser confocal microscopy in all infected corneas. Conclusion: Further refinement of currently available ophthalmological tools is required to aid in vivo visualization of herpes simplex keratitis using fluorescein isothiocynate-labeled antibodies.