In vitro eye irritation testing using the open source reconstructed hemicornea - a ring trial.

Area of Science:

• Toxicology
• Ophthalmology
• In vitro testing

Background:

• Reliable in vitro methods are needed for classifying eye irritating chemicals.
• Existing methods require validation across multiple laboratories.
• Open source 3D reconstructed hemicornea models offer a promising alternative.

Purpose of the Study:

• To assess the inter-laboratory transferability and reproducibility of two new in vitro methods for eye irritant classification.
• To evaluate the performance of these methods using 3D reconstructed hemicornea models.
• To determine the suitability of these methods for regulatory use.

Main Methods:

• A ring trial involving three independent laboratories was conducted.
• Two distinct in vitro methods utilizing open source 3D hemicornea models were tested.
• Method 1: Histological analysis of injury depth. Method 2: Tissue viability assessment of epithelium and stroma.

Main Results:

• The second method demonstrated 100% between-laboratory reproducibility, while the first achieved 62.5%.
• Both methods successfully discriminated Category 1 (severe) eye irritants from non-irritants.
• Optimization is needed to improve selectivity between No Category and Category 2 irritants.

Conclusions:

• The second in vitro method shows high reliability and potential for classifying eye irritating chemicals.
• Both methods can be utilized in a top-down approach for hazard identification.
• Further refinement is necessary for precise classification of milder irritants.