Unfortunately, other nonsmoking aircrew members are also exposed to these CO-induced hypoxic effects. The effects may be prolonged at higher altitudes. Smoking aboard operational aircraft can create problems in optical clarity. Cigarette smoke deposits a dirty film on windscreens, canopies, HUD combiner lenses, visors, and spectacles that can reduce acuity and contrast sensitivity, both during the day and at night. The unique properties of nicotine to penetrate into narrow spaces and to chemically adhere to most surfaces led airframe manufacturers to use nicotine staining to mark the locations of structural failures and loss of pressurized cabin integrity.
Smoking is obviously dangerous on the battlefield at night.
Smoke may also affect inflight eye comfort in smokers and nonsmokers, especially in contact lens wearers. A smoke-contaminated cabin atmosphere could become a problem in the future as the number of aircrew wearing contact lenses dramatically increases. Finally, the chronic effects of active or passive cigarette smoking must be considered. These effects may alter the dark focus of accommodation and lower the age of onset of presbyopia and bifocal wear. It would be exceedingly difficult to obtain a definitive resolution to this controversial issue.