What Causes Watery Eyes?

My 2-1/2 year old daughter used to get some watery eyes when watching tv which is usually at a distance. Mostly no watery eyes when watching ipad if it s closer. It has gotten worse in last 2-3 weeks and now getting some watery eyes even sometimes when she watches ipad. She s also having cold since last 4 weeks. We got a eye-check up done 2 months ago and they advised to check again in 6months as she doesn t seem nearsighted right now. What could be the reason for worsening watery eyes? Any deficiency? Or cold?