Stephen Criddle, a non-smoker says, "I just figured it caused cancer and stuff like that." That's something we've known for a while, but now a study in the Medical Journal of Australia reports the 4,000 chemicals in one cigarette, all those inhaled chemicals, can cause blindness over time. Ophthalmologist Dr. Charles Cozean says, "It's gradual, each cigarette takes it's toll. It takes that toll by constricting blood vessels. The blood vessels have a lining called endothelium, and every time you smoke a cigarette it takes a little bit of the endothelium away, and that's irreplaceable." Smoking attacks the optic nerve, destroys macular arteries, and can cause cataracts in a person's eyes. Something that makes ex-smokers glad they've stopped.