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Ocular Toxicity Test Method Evaluations

Ocular toxicity testing, one of the four most commonly conducted product safety tests, is conducted to identify ocular corrosives (substances that cause permanent eye tissue damage) and ocular irritants (substances that cause temporary eye tissue damage). Evaluation of test methods that reliably identify ocular corrosives and irritants while replacing, reducing, and refining animal use is a high priority for NICEATM and ICCVAM.

OptiSafe Test Method

OptiSafe is an in vitro test method in which a test substance is applied to a semipermeable membrane. Damage to macromolecules in the membrane is measured to assess the test substance’s potential to cause eye irritation.

NICEATM coordinated a validation study of the OptiSafe test method to demonstrate the accuracy and reliability of the method among the test method developer’s laboratory and two naïve laboratories. Members of the ICCVAM Ocular and Dermal Irritation Workgroup comprise the validation management team for the study, and the study received support from an NIEHS Small Business Innovation Research grant. Testing was completed in late 2017. A summary of study results was presented (Choksi et al.) at the 2018 Society of Toxicology meeting; data analyses and an associated report will be submitted for publication in 2018.

Short Time Exposure Test

The short time exposure (STE) test is an in vitro test for identifying ocular eye injury hazard potential. NICEATM compared STE test data with data generated using the traditional rabbit eye test. The results of the comparison, including comments from external reviewers, was included in a proposal to the Organisation for Economic Co-operation and Development (OECD) for a test guideline for the STE test. Test Guideline 491 for the STE test was formally adopted in July 2015.

In Vitro Test Methods to Identify Ocular Irritants

ICCVAM evaluated and produced recommendations, published in 2006 and 2010, for in vitro test methods used to identify ocular irritants.

  • The 2006 report recommended using the bovine corneal opacity and permeability and the isolated chicken eye test methods in a weight-of-evidence approach to identify products with the potential to cause permanent or severe eye injuries. Substances that test positive in these assays can be classified as ocular corrosives or severe irritants without testing in animals or additional in vitro eye irritation methods.
  • The 2010 report recommended that the Cytosensor microphysiometer (CM) test method be used as a screening tool to identify certain types of water-soluble substances that cause permanent or severe eye injuries. ICCVAM also recommended that the CM test method could be used to identify substances that do not require any hazard labeling for eye irritation.

In Vitro Testing Strategy for Ocular Hazard Classification and Labeling of Antimicrobial Cleaning Products

The U.S. Environmental Protection Agency (EPA) collaborated with seven consumer product companies to develop an in vitro testing strategy to assess the eye irritation potential of antimicrobial cleaning products. ICCVAM evaluated the proposed strategy and recommended further studies to characterize its usefulness and limitations. EPA considered the ICCVAM recommendations in development of final guidance on use of the strategy, which was released in 2013 and updated in 2015.