Validation of the OptiSafe™ eye irritation test

Expansion of the application domain of a macromolecular ocular irritation test (OptiSafe™)

“…The OS macromolecular test was conducted as previously described ( Choksi et al, 2020 ; Lebrun et al, 2021a , 2022b ) and is briefly described below.…”

“…After incubation at 31 °C, the OD is measured with a spectrophotometer. The resulting OD and pH values are compared with quality controls and a standard curve to generate a score (see Choksi et al, 2020 for procedure details and flow chart).…”

“…Opti-Safe ™ (“Optimized for Safety”) is a shelf-stable in chemico test method that consists of a proprietary macromolecular test matrix that is used to quantify the potential of an unknown test material to cause eye irritation or eye damage. Damage to macromolecules results in the loss of cell viability, and the extent of measured macromolecular damage is used to predict the toxicity of the material being tested ( Lebrun, 2018 ; 2021 ; Lebrun et al, 2021a , 2021b ; Lebrun et al, 2022 ; Choksi et al, 2020 ; Lebrun et al, 2019 , 2021a , 2021b , 2022a , 2022b ).…”

“…Foaming materials (“surfactants”) were excluded from the study, and there were only 11 GHS Category 1 chemicals. For the three-lab blind transferability phase, when results were combined based on the majority classification for the GHS classification, the accuracy was 89%, the false-negative (FN) rate was 0%, the false-positive (FP) rate was 23%, the sensitivity was 100%, the specificity was 77%, and the balanced accuracy was 88.5% ( Choksi et al, 2020 ). Additional chemicals were selected by ICCVAM for evaluation of the test’s application domain; these materials were tested by the lead lab only in the “application domain phase.” Based on overall results from the three-lab blind transferability study and the blind application domain study, the test method accuracy for the GHS system was 80%, the FN rate was 0%, the FP rate was 40%, the sensitivity was 100%, the specificity was 60%, and the balanced accuracy was 80% ( Lebrun et al, 2021a ).…”

“…All prior OS-coded validation study chemicals were then retested ( Lebrun et al, 2022a ). These chemicals included the prior coded validation chemicals described above ( Choksi et al, 2020 ; Lebrun et al, 2021a ). Based on the retesting of chemicals, for the detection of GHS NC, the addition of an antioxidant to levels found in tears lowered the FP rate from 40.0% to 22.2%.…”