Figure 6. Plastic sections confirm potentiation of ONL loss by dark maintenance and protection by nicotinamide against LD. A: Plastic sections were cut from eyes along a superior to inferior meridian encompassing the optic nerve, and were stained with 0.1% Toluidine Blue. Representative photo-micrographs were taken of the mid superior and mid inferior regions from Control group; 1 h light-induced damage dark-maintained (1 h LD (dark)) group; LD + i.p. injection of nicotinamide (1h LD (dark) + N); and 2 h of LD dark maintained (2 h LD (dark)) versus non dark maintained (2 h LD (light)) as marked. B: The mean number of nuclei at increasing distance from the optic nerve on the superior and inferior sides was averaged and plotted as a function of distance from the optic nerve for each of the experimental conditions above (n=6). # signifies difference from LD at p<0.05 by one-way ANOVA and a Bonferroni test.