Abstract
Purpose :
To evaluate the effect of the photoactivated chromophore corneal cross-linking (PACK-CXL) procedure as preventative therapy for Fusarium keratitis, using ex vivo human corneas and a histological staining technique.
Methods :
Sixteen ex vivo human corneas were randomly divided into four study groups: uninfected, untreated control (C), infected only (I), cross-linked then infected (XI) and infected then cross-linked (IX). All infected corneas were inoculated with Fusarium oxysporum spores. The PACK-CXL technique was performed on the cross-linked then infected group 24h pre-inoculation, and on the infected then cross-linked group 24h post-inoculation. For the PACK-CXL procedure, the corneas were debrided of epithelium then 1% (w/v) isotonic riboflavin was applied dropwise at 5-minute intervals for 30 minutes and during the course of UV-A cross-linking for another 30 minutes. All corneal buttons were PFA-fixed, embedded in OCT, sectioned at 30 µm thickness and haematoxylin and eosin (H&E) stained. The stained sections were imaged using a Zeiss Axiostar microscope, and the depth of fungal hyphal penetration within the stromal tissue was measured using ImageJ.
Results :
The depth of fungal hyphal penetration in the central region of the cornea was significantly less in the IX group than in the I group (p=0.001) and the XI group (p=0.039), and significantly less in the XI group than in the I group (p=0.015). However, there was no significant difference in the peripheral infection between the inoculated groups. Furthermore, in terms of the central versus peripheral infection among each group, there was no significant difference observed within the I and XI groups, while the difference was significant in the IX group (p=0.015).
Conclusions :
The PACK-CXL therapy seems to be a valuable approach in reducing the depth of Fusarium hyphal penetration in the corneal tissues. However, riboflavin-activated PACK-CXL was not effective as a preventative measure for Fusarium keratitis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.