Values are expressed as medians, Median representation: 0, absence of opacification (gridlines clearly visible); 1, slight degree of opacification (minimal clouding of gridlines and gridlines still visible); 2, diffuse opacification involving almost the entire lens (moderate clouding of gridlines and gridlines faintly visible); 3, extensive thick opacification involving the entire lens (total clouding of gridlines and gridlines not seen at all). Statistical analyses were performed by using Wilcoxon rank sum test. The asterisk indicates a p<0.05 B versus A, the double asterisk indicates a p<0.01 B versus A, the sharp (hash mark) indicates a p<0.05 B versus E and F, and the double sharp indicates a p<0.01 B versus E and F. Group A was the control group, group B was the hyperoxia-exposed rabbit lenses group, group C-F were the hyperoxia-exposed, NAC-treated groups: 5 mM NAC (group C), 10 mM NAC (group D), 20 mM NAC (group E), and 40 mM NAC (group F).