Changing concepts of ocular irritation evaluation: pitfalls and progress

Quantitative Characterization of Acid- and Alkali-Induced Corneal Injury in the Low-Volume Eye Test

“…These values are substantially below the -~-20°7o depth of injury for 8% NaOH, which was observed in the first study. This variation in response between different groups of animals has been noted previously and is recognized as a major limitation of ocular irritation testing in the rabbit model (8,30,32,33).…”

“…Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

“…For eyes treated with 10% acetic acid, 2% NaOH, and 8% NaOH, the mean number of ethidium homodimer-stained nuclei was 0.2 ± 0.5, 0.0 ± 0.1, and 13.8 ± 10.0 cells at 3 hours and 4.4 ± 1.6, 0.2 ± 0.4, and 10.0 ± 8.0 cells at 1 day, respectively (Table 2). At In this separate study, the severity of the initial injury following application of 3% acetic acid, 10% acetic acid, 2% NaOH, and 8% NaOH (Table 3) was substantially less than that observed in the first study, which focused on initial injury at 3 hours and 1 day postdosing (Table 2) (8,30,32,33 (Table 3). Eyes treated with 8% NaOH, which showed a significant decrease in epithelial cell size at 3 hours compared to control and 3% acetic acid-treated eyes, remained significantly decreased at 1 day (Table 3 and Figure 4A).…”

“…Based on macroscopic examination, in the present study, the irritancy potential of the different concentrations of acetic acid and NaOH was as follows: 3% acetic acid < 2% NaOH < 10% acetic acid < 8% NaOH; these results are consistent with previous studies that showed that these materials cause slight, mild, moderate, and severe ocular irritation, respectively (15 Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

Quantitative Characterization of Acid- and Alkali-Induced Corneal Injury in the Low-Volume Eye Test

“…These values are substantially below the -~-20°7o depth of injury for 8% NaOH, which was observed in the first study. This variation in response between different groups of animals has been noted previously and is recognized as a major limitation of ocular irritation testing in the rabbit model (8,30,32,33).…”

“…Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

“…For eyes treated with 10% acetic acid, 2% NaOH, and 8% NaOH, the mean number of ethidium homodimer-stained nuclei was 0.2 ± 0.5, 0.0 ± 0.1, and 13.8 ± 10.0 cells at 3 hours and 4.4 ± 1.6, 0.2 ± 0.4, and 10.0 ± 8.0 cells at 1 day, respectively (Table 2). At In this separate study, the severity of the initial injury following application of 3% acetic acid, 10% acetic acid, 2% NaOH, and 8% NaOH (Table 3) was substantially less than that observed in the first study, which focused on initial injury at 3 hours and 1 day postdosing (Table 2) (8,30,32,33 (Table 3). Eyes treated with 8% NaOH, which showed a significant decrease in epithelial cell size at 3 hours compared to control and 3% acetic acid-treated eyes, remained significantly decreased at 1 day (Table 3 and Figure 4A).…”

“…Based on macroscopic examination, in the present study, the irritancy potential of the different concentrations of acetic acid and NaOH was as follows: 3% acetic acid < 2% NaOH < 10% acetic acid < 8% NaOH; these results are consistent with previous studies that showed that these materials cause slight, mild, moderate, and severe ocular irritation, respectively (15 Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

Quantitative Characterization of Acid- and Alkali-Induced Corneal Injury in the Low-Volume Eye Test

“…These values are substantially below the -~-20°7o depth of injury for 8% NaOH, which was observed in the first study. This variation in response between different groups of animals has been noted previously and is recognized as a major limitation of ocular irritation testing in the rabbit model (8,30,32,33).…”

“…Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

“…For eyes treated with 10% acetic acid, 2% NaOH, and 8% NaOH, the mean number of ethidium homodimer-stained nuclei was 0.2 ± 0.5, 0.0 ± 0.1, and 13.8 ± 10.0 cells at 3 hours and 4.4 ± 1.6, 0.2 ± 0.4, and 10.0 ± 8.0 cells at 1 day, respectively (Table 2). At In this separate study, the severity of the initial injury following application of 3% acetic acid, 10% acetic acid, 2% NaOH, and 8% NaOH (Table 3) was substantially less than that observed in the first study, which focused on initial injury at 3 hours and 1 day postdosing (Table 2) (8,30,32,33 (Table 3). Eyes treated with 8% NaOH, which showed a significant decrease in epithelial cell size at 3 hours compared to control and 3% acetic acid-treated eyes, remained significantly decreased at 1 day (Table 3 and Figure 4A).…”

“…Based on macroscopic examination, in the present study, the irritancy potential of the different concentrations of acetic acid and NaOH was as follows: 3% acetic acid < 2% NaOH < 10% acetic acid < 8% NaOH; these results are consistent with previous studies that showed that these materials cause slight, mild, moderate, and severe ocular irritation, respectively (15 Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

Quantitative Characterization of Acid- and Alkali-Induced Corneal Injury in the Low-Volume Eye Test

“…These values are substantially below the -~-20°7o depth of injury for 8% NaOH, which was observed in the first study. This variation in response between different groups of animals has been noted previously and is recognized as a major limitation of ocular irritation testing in the rabbit model (8,30,32,33).…”

“…Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”

“…For eyes treated with 10% acetic acid, 2% NaOH, and 8% NaOH, the mean number of ethidium homodimer-stained nuclei was 0.2 ± 0.5, 0.0 ± 0.1, and 13.8 ± 10.0 cells at 3 hours and 4.4 ± 1.6, 0.2 ± 0.4, and 10.0 ± 8.0 cells at 1 day, respectively (Table 2). At In this separate study, the severity of the initial injury following application of 3% acetic acid, 10% acetic acid, 2% NaOH, and 8% NaOH (Table 3) was substantially less than that observed in the first study, which focused on initial injury at 3 hours and 1 day postdosing (Table 2) (8,30,32,33 (Table 3). Eyes treated with 8% NaOH, which showed a significant decrease in epithelial cell size at 3 hours compared to control and 3% acetic acid-treated eyes, remained significantly decreased at 1 day (Table 3 and Figure 4A).…”

“…Based on macroscopic examination, in the present study, the irritancy potential of the different concentrations of acetic acid and NaOH was as follows: 3% acetic acid < 2% NaOH < 10% acetic acid < 8% NaOH; these results are consistent with previous studies that showed that these materials cause slight, mild, moderate, and severe ocular irritation, respectively (15 Another finding in this study is the variable depth of injury and ocular irritation responses observed between different groups of animals. Variability has been noted previously with regard to animal testing, and this variability is thought to be related to variations in animals and methods of application (8,30,32,33). In the current study, the same individual was responsible for the dosing of animals, and all schedules and procedures were rigorously followed.…”