OECD TEST GUIDELINE 492 - The Eye Irritation Test (EIT)
Reconstructed Human Cornea-like Epithelium Method
What is OECD Test Guideline 492?
OECD TG 492 or The Eye Irritation Test (EIT) is an OECD-approved in vitro non-animal test method for
identifying chemicals and mixtures that may be irritating to the corneal epithelium. This in vitro test method
utilizes reconstructed human corneal epithelium (RhCE) models in an acute exposure assay to support
regulatory labeling requirements, according to the United Nations Globally Harmonized System of Classification
and Labelling of Chemicals(UN GHS).
OECD TG 492 is used widely in the cosmetics, personal care, household products, chemical, pharmaceutical, and biotech industries.
These 3D tissues are metabolically and mitotically active and release cytokines that occur in irritation and inflammation
in vivo (IL-6, IL-8, TNFα). This in vitro ocular irritation test is based upon the assessment
cytotoxicity following exposure to a test article, at three time points (additional time points may be added). Cytotoxicity is expressed
as a decrease in mitochondrial conversion of MTT [(3-4,5-dimethyl thiazole 2-yl) 2,5-diphenyltetrazoliumbromide], into a blue formazan
salt that is quantitatively measured after extraction from the tissues.
- Product Development/Efficacy
- Claims Substantiation
- Safety Assessment
- Target Organ Research
MB Research has extensive experience in the use of 3D tissues and in vivo ocular toxicology testing.
Other In vitro/Alternative Eye Irritation Tests
OptiSafe™ Eye Irritation Test
- OptiSafe™ In Vitro Eye Irritation Test
- An in vitro test method in which a test substance is applied to a semi-permeable membrane. Damage to macromolecules in the membrane is
measured to assess the test substance’s potential to cause eye irritation.
- Can be used to determine the irritation potential of cosmetics, creams, and a wide variety of consumer products. Results are presented as GHS, EPA classifications, an ocular irritation score and class
Porcine Cornea Reversibility Assay (PorCORA)
- Uses excised porcine cornea normally discarded
- Corneas maintained in culture for up to 21 Days
- Measures "Days to Recover" after exposure to possible Irritants
- Allows discrimination between Severe Irritant and Ocular Corrosive
Chorioallantoic Membrane Vascular Assay (CAMVA)
- Uses fertilized chicken eggs on embryonic day 10 or 14 of development
- Measures hemodynamic effects, injury, and anti-angiogenic effects to the membrane microvasculature
- Especially useful for alcohol-containing formulations
HET-CAM - Hen's Egg Test - Chorioallantoic Membrane (HET-CAM)
- Uses fertilized chicken eggs
- INVITTOX PROTOCOL Number 47
Bovine Corneal Opacity and Permeability Assay (BCOP)
- Uses excised bovine corneas normally discarded
- Measures two endpoints; 1) changes in opacity, reflecting protein denaturation and corneal injury, and 2) fluorescein permeability
reflecting damage to corneal epithelium
- Optional histological endpoint is available (H & E staining)
- Measurement of pro-inflammatory mediators in liberated corneal
cells (by flow cytometry or ELISA)
Replacement Ocular Battery (ROBatt)
- Uses tiered testing strategy of alternative ocular irritation assays (CAMVA, BCOP, PorCORA, PorFocal) to determine regulatory classification of a test material without the use of live animals.
- Currently Under Development