Purpose Corneal donor tissue is in short supply. Only a fraction of the demand is satisfied. The tissues can vary in quality and sometimes have limited use. To address the issue, the generation of artificial corneal grafts is intensively researched.

Various aspects of these prototypes need to be tested, ranging from structural integrity to cellular morphology. Our Ex Vivo Eye Irritation Test (EVEIT) is based on an air-lift organ culture system, where we currently are using rabbit corneas from food industry. We constantly expanded our capabilities in quantifying various parameters concerning metabolism, structural integrity and optical properties. This also opens up the possibility of using the system as a testing platform for prototypical artificial corneal constructs.

Methods Various ophthalmological aspects can be investigated using the EVEIT system:

• Self–healing of superficial injuries and morphological characteristics can be observed over several days by live–tissue staining macroscopy.

• Metabolic parameters are recordable via the endothelial nutrient supply mechanism.

• Acute changes in internal pressure can be measured in the artificial anterior chamber with high resolution.

• Corneal barrier functions and pharmacokinetic properties can be quantified using photometric analysis methods.

• Dry–Eye model and established corneal edema models can be employed to test the efficacy of potential therapeutics

• Advanced 3D design and printing methods allow us to quickly adapt the bioreactor, for example, to incorporate human corneas or to improve the mobility of the system.

• In order to comply with the 3Rs principle, testing of several different chemicals on one cornea is now also possible with the aid of automated multi–application

• Recent developments of the EVEIT system include the engineering of an artificial eyelid model.

Results Our long experience in using and optimizing the EVEIT system led to a unique adaptability to accommodate different testing conditions and requirements. Established disease models such as corneal edema and in dry eye syndrome (in process) are involved in testing new drugs.

Conclusion Our established EVEIT system, in addition to its experimental capabilities, could contribute to the development of artificial corneal grafts in the future, as we have shown in previous work. The flexibility of the system allows us to adjust and improve an enormous range of test conditions and parameters.