The rabbit ocular surface has been used for many years as a reliable comparison for the study of human corneal injuries. This work aimed to create a standardised corneal epithelial injury using an alkali insult, which results in a type III healing response with wound healing. The ultimate aim is the use of this in vivo injury model to test novel ocular bandages and substrate treatments.Methods
De-epithelialisation first required in vitro optimisation for reproducibility before use in in vivo rabbit models. Corneas obtained from New Zealand White rabbits were de-epithelialised with sodium hydroxide (NaOH) solution using a range of concentrations, durations and modes of application. The injury area, depth and severity were assessed using haematoxylin and eosin staining and transmission electron microscopy. The optimised in vitro model was applied to an in vivo pilot study in rabbits and tested for reproducibility using normal and fluorescein slit lamp images.Results
In vitro optimisation revealed that higher NaOH concentrations and extended durations caused undesirable irreversible damage to the cornea. Lower concentrations and durations produced the injury required. The injury model was established in an in vivo pilot study using our optimal parameters and tested to see if a chemical burn with little variation in area or severity could be achieved. Following 48 hour treatment we were able to detect reliable wound healing using our refined model.Conclusion
The in vitro optimisation showed us parameters that were sufficient to de-epithelialise the cornea, creating an injury without causing stromal damage. The model is now in use in vivo, to test the biocompatibility and efficacy of various ocular surface substrate treatments.