Smoking is strongly related to poor health generally and the eyes are no exception.  Smoking reduces the critical blood supply to the eyes because it narrows the blood vessels and thickens the blood.  It directly accelerates the development of cataract and of particular importance significantly increases (by two to four times) the probability of macular degeneration.  Smokers are over 80 per cent more likely to suffer dry eye disease than non-smokers, and contact lens wearers who smoke also encounter more difficulties with their wear than those who don't.