Contact lenses are made from different plastics and silicones that have different characteristics and while some have more water content than others - all lenses are subject to evaporation while on the eye. In other words, the environment sucks the water out of the lenses. The rate of this happening depends on many factors: humidity, wind, temperature, your health, what medicines you are taking, how much you blink, the care system you use, how clean the lenses are, etc. A few lenses are now available that are made from plastics that resist dehydration and evaporation.
*You could try and alleviate the dry eye condition itself by asking your doctor about the possibility of lacrimal or punctal occlusion, which plugs up the tear drainage system to keep more moisture in your eyes.