Some believe that for some dry eye is caused by a lack of good fats in the diet. Some have found relief by using cod liver oil pills, though those can be dangerous if taken long-term. There was a product used by some of my customers when I managed health foods stores called Cod Liver Oil Skin Formula by TwinLabs. Helped some, but didn't cure the problem. Could be a lack of antioxidants such as lutein that are very good for the eyes (found in green foods). There are many vision formulas that contain antioxidants that help the eye. The most prevalent one in the eye is also the most prevalent one in the liver, glutathione, which you can't really get in supplement form that is absorbed but you can get by juicing wheat grass. But these are just ideas I'm throwing out there, don't really know.