OECD TG 405 is the “Acute Eye Irritation/Corrosion” standard, which is listed under Section 4 (Health Effects) of the OECD Test Guidelines for the Testing of Chemicals. It was first adopted in 1981 and updated in 2023. The test is used to evaluate the reversible irritation or irreversible corrosive damage caused by a substance following a single application to the eye.
The current version of OECD TG 405 follows a sequential testing strategy. The main objective of this approach is to minimize the use of animals and to prevent substances that can cause severe eye damage from causing unnecessary suffering to the animals:
- Evaluation of the available data: Structural similarities, the scientific literature, previous test results, and physicochemical properties (e.g., pH ≤ 2 or ≥ 11.5) are evaluated.
- In vitro tests: Where appropriate, validated in vitro methods such as OECD TG 437 (Bovine Corneal Opacity and Permeability, BCOP), OECD TG 438 (Isolated Chicken Eye, ICE), or OECD TG 492 (Reconstructed Human Cornea-like Epithelium, RhCE) are used.
- In vivo test (TG 405): This test is conducted only if in vitro data are insufficient or if required for regulatory reasons.
The basic principle of the in vivo test is as follows:
- The test substance is typically administered as a single dose into one eye of an albino rabbit (usually 0.1 ml or 0.1 g); the other eye serves as a control.
- After administration, the eye is generally not rinsed (rinsing is performed only in exceptional cases and must be justified).
- The cornea, iris, and conjunctiva are evaluated using the standardized Draize rating system:
- Corneal opacity: 0–4
- Iris lesions: 0–2
- Conjunctival redness: 0–3
- Conjunctival edema: 0–4
- Monitoring is generally conducted at 1, 24, 48, and 72 hours; if the effects persist, the monitoring period may be extended to up to 21 days.
- The test usually begins with a single animal; if severe corrosion or severe irritation is observed, the test is discontinued. Otherwise, it is expanded to include up to three animals in total.
- If necessary, corneal damage is assessed using fluorescein staining; a histopathological examination may be performed.
The main parameters reported in the study are:
- The amount of material applied and the application conditions
- Assessment scores for the cornea, iris, and conjunctiva (for each animal and each observation time point)
- Average of Ratings and Assessment of Reversibility
- Presence and extent of a corrosive effect
- Fluorescein staining and histopathological findings, if applicable
- GHS/CLP category for serious eye damage/eye irritation (Category 1, 2A, 2B, or not classified) and rationale
- Animal species used, sex, age, and environmental conditions
- Data on Measurement Uncertainty and Repeatability
Why is this being done?
OECD Test Guideline 405 is conducted for the following scientific and regulatory purposes:
Definition of ocular corrosivity: Determination of a substance's potential to cause irreversible damage to the eye
Definition of eye irritation: Determination of a substance’s potential to cause a reversible inflammatory reaction in the eye. GHS/CLP classification: Determination of the category for serious eye damage/eye irritation (Categories 1, 2A, 2B) and specification of labeling requirements (H318, H319, etc.) Classification according to transport regulations: Appropriate classification under UN/ADR Priority of animal welfare (3Rs): Reduction of animal testing through a tiered testing strategy and validated in vitro methods; prevention of unnecessary suffering in animals caused by substances that can lead to serious eye damage Support for regulatory submissions: Used in safety assessments of chemicals, pesticides, biocidal products, cosmetics, pharmaceuticals, and medical devices; Product safety and labeling: Determination of warning statements and safety measures to protect consumers and workers; Weight-of-evidence approach: Contribution to the holistic assessment of the substance in conjunction with other toxicological, physicochemical, and exposure data
OECD Test Guideline 405 does not, on its own, provide information on systemic toxicity, skin irritation, or sensitization; these effects must be evaluated in separate tests (e.g., TG 402, TG 404, TG 406, TG 442).
The results should be interpreted in the context of the substance's physicochemical properties, the in vitro data, and the exposure assessment.
As part of our nano-testing services, we conduct acute eye irritation/corrosion tests in accordance with OECD TG 405 within our accredited laboratory infrastructure and under our quality management system, applying scientific rigor. Our scope of services includes the following:
Step-by-Step Testing Strategy and Experimental Design
- Development of a test plan in accordance with the stepwise testing strategy of OECD TG 405
Evaluation of available data, structural similarities, and physicochemical properties (particularly pH)
Where appropriate, prioritization of in vitro tests (TG 437, TG 438, TG 492) and evaluation of their results; scientific justification of cases in which an in vivo test is required; compliance with ethical approval and animal welfare requirements; establishment of criteria for early termination
To obtain information on planning a sequential testing strategy, in vitro preliminary assessment, study design, sample acceptance criteria, testing schedule, and reporting procedures for your acute eye irritation/eye corrosion studies in accordance with OECD TG 405, please contact Nano-Test.