Air leaking from the mask at the bridge of the nose and over the eyes during sleep will cause the eyes to dry out. The most common reason for air leaking at the nose bridge is that the mask is too big or too long for the nose.
We would suggest you resize your mask to be sure you have the best size. A mask that has an adjustment at the bridge may also be helpful in getting a good fit. Nasal pillow or nose cushion devices which do not rest on the nose are also an option.
It is not advisable to tighten the headgear to eliminate the air leak. Pressure from a mask that is too tight will cause bruises and even open sores if applied long enough.