Your eyes would cry underwater normally because you eyes will still produce salt water. Crying underwater wouldn't be like crying out of water. I say this because if your underwater, water surrounds you on every side of your body. The slat water that you'd cry would only add an extremely small amount of more water to whatever body of water your in. Out of water, your tears fall down your face if enough potential energy is built up. Underwater, you won't even notice that your crying. Plus, when underwater, you'd probably be having a good time and wouldn't want to cry about something hard in life!
Hopefully this helps!! :)