No tears in daughters eyes

Does anyone have a child that has no tears? My daughter is 4 years old now and has NEVER had tears. I have brought it up at every checkup she has had but her pediatrician says that her eyes seem to be lubricated fine and not to worry about it. I am concerned when those hormones start flaring up during the teenage years and beyond that she won't be able to release tension through crying (have a good cry once in awhile)! I just don't think her pediatrician understands this because of him being a man. Are there any FEMALE adults out there that have the same problem? Does it cause a problem or do you not notice it at all? Am I being crazy? Help!