OECD 492 Flashcards
What is the difference between Serious Eye Damage and Eye Irritation?
Serious Eye Damage: Nonreversible tissue damage or vision decay after exposure to a chemical (UN GHS Category 1). Eye Irritation: Fully reversible changes after chemical exposure (UN GHS Category 2).
What was the traditional testing method for assessing eye damage/irritation?
Animal testing (OECD Test Guideline 405).
What does the In Vitro Test Method aim to identify?
Chemicals that don’t require classification for eye damage or irritation.
What are the four validated test methods using RhCE models?
- EpiOcular™ EIT
- SkinEthic™ HCE EIT
- LabCyte CORNEA-MODEL24 EIT
- MCTT HCE™ EIT
What is a limitation of In Vitro methods for eye damage classification?
These methods do not differentiate between serious eye damage (Category 1) and eye irritation (Category 2).
What are the two approaches recommended for testing strategy?
- Bottom-Up: Used when a chemical is unlikely to cause significant irritation.
- Top-Down: Used for chemicals expected to cause serious eye damage.
What is the purpose of the guideline regarding eye hazard potential?
Evaluates a chemical’s eye hazard potential based on cytotoxicity in RhCE tissue constructs.
What are the performance standards used for in vitro RhCE-based methods?
To validate new or modified methods, ensuring they meet OECD guidelines.
What is the range of chemicals validated under the guideline?
A broad range including mono- and multi-constituent substances, covering various chemical classes and physical states.
What types of substances are applicable under the guideline?
Substances, mixtures, and various physical states (liquids, solids, semi-solids, waxes).
What is the reproducibility percentage for EpiOcular™ EIT?
95% within-laboratory reproducibility.
What are the viability thresholds for identifying chemicals as No Category?
- EpiOcular™ EIT: Viability > 60%
- SkinEthic™ HCE EIT: Viability > 60%
- LabCyte CORNEA-MODEL24 EIT: Viability > 40%
- MCTT HCE™ EIT: Viability > 35% for liquids and > 60% for solids.
What is required for laboratories before using RhCE test methods for regulatory purposes?
Demonstration of technical proficiency by correctly predicting the fifteen proficiency chemicals.
What are the recommended positive control substances?
- Methyl acetate
- Ethanol
- Lauric acid
What is the purpose of the TD Assay?
A standardized quantitative method for measuring tissue viability, compatible with 3D tissue constructs.
What is the absorbance measurement wavelength for MTT?
570 nm.
What is the primary mechanism of chemical-induced eye irritation?
Chemical penetration and damage to cells.
What types of interference can affect viability measurements?
Chemicals absorbing light in the same range as the vital dye or reducing the dye directly.
What are the types of RhCE tissue constructs mentioned?
- EpiOcular™ OCL-200
- SkinEthic™ HCE/S
- LabCyte CORNEA-MODEL24
- MCTT HCE™
True or False: The guideline excludes gases and aerosols.
True.
What is the significance of the barrier function in RhCE tissue constructs?
It resists penetration by cytotoxic substances.
What type of cells are used to create RhCE tissue constructs?
Human-derived epidermal keratinocytes, immortalized corneal epithelial cells, or primary human corneal epithelial cells.
What is the expected accuracy for SkinEthic™ HCE EIT?
84% accuracy.
Fill in the blank: The test chemical is applied topically to at least ______ RhCE tissue constructs.
two three-dimensional
