(c)2006 Albert Donnay
Pop Quiz
uGiven what you now know about the role of CO in sensitization, what results would you expect from a study of:
u    Dark Adaptation of the Eye [and subsequent light sensitivity]
during Carbon Monoxide Exposure in Smokers and Nonsmokers 
(von Restorff W and Hebisch S, Aviation, Space, and
Environmental Medicine, 1988;59(10):928-931)
uAfter exposing smokers and non-smokers to 5000 ppm CO for
5 minutes, the dark adaptation time increased 16% in both groups, but the subsequent light sensitivity of their dark adapted eyes was much more significantly reduced among the smokers (36 to 40%) than the non-smokers (7 to 17%). 
uThis shows that
a) CO exposure impairs habituation time, even in smokers, and
b) Smokers are less sensitive to light when exposed to more CO.