Dry eye is very common. The overwheming majority of patients that come for a LASIK consultation have dry eye. This must be addressed before surgery to optimize the visual result and provide the greatest comfort after surgery. The leading cause of dry eye in young people is long-term contact lens wear. Contact lenses desensitize the cornea over time resulting in decreased tear production. These patients often do not know their eyes are dry until it is very advanced because they no longer can sense the foreign body sensation commonly associated with dry eye.  Birth control pills are another common cause of dry eye. Other medications that can cause dry eye include antidepressants, antihistamines and antihypertensives.  Dry eye is nearly ubiquitous in woman over the age of forty five. The incidence  of  dry eye is less in men as they age because men have higher levels of testosterone that is protective.