A new research suggests that for each cigarette a pregnant woman lights up each day, she raises her baby's risk of strabismus by 5 percent. Further, the effect of smoking on the debilitating eye disorder may become more potent later in pregnancy. But strabismus is a common condition, affecting some 2 to 3 percent of children, not much is known about its causes. Exposure in the womb to harmful substances may be one cause of strabismus. Nicotine and other substances in tobacco, alcohol and caffeine all affect the brain in some way.