Here's some info:

"Many people get dry eye because they have a potassium deficiency. This obviously can be cured by eating a banana" [Source]

"Eating a banana every day can be very useful, if you suffer from dry eyes. Since bananas are very rich in potassium, they help to control the balance of sodium and release of fluid in your cells, which results in preventing dry eyes. Simply eat banana a day and get rid of dry eyes." [Source]

Also: http://www.lookchem.com/Chempedia/Health-and-Chemical/15811.html

Make a banana face mask: http://www.ehow.com/how_2099414_make-banana-face-mask.html