Figure 3. Decreases in mouse surface LEC cell density with age and X-irradiation using vital dye staining of whole lenses. The cell density (cells/mm²) was determined by counting nuclei stained with the vital dye Hoechst 33342 on the lens surface in unirradiated controls (green squares) and X-irradiated mouse lenses (red circles). X-Irradiation of these mice was at 3 months of age. The error bars represent the standard error of the means, and stars indicate a significant difference from age matched control values using 1 tail Mann–Whitney test (the p values: **, p<0.02, ***, p<0.002). Each point represents the mean of 4–6 mice.