XN treatment decreases the number of TUNEL-positive cells following toxic light exposure. Groups of XN- and vehicle-treated mice received toxic light exposure and were euthanized immediately, 6 hours, or 24 hours after exposure. Retinas were collected, sectioned, and used for a TUNEL assay. XN-treated mice exhibited significantly fewer TUNEL-positive cells compared to the vehicle-treated group at both 6 hours and 24 hours post-toxic light exposure (*P < 0.0001 vs. other groups; Student's t-test, error bars represent SEM). Lower panels are representative images of retinal sections used in quantification.