@Izzie,
That's interesting - it could be a combo of stress and eye strain. I'm famous to myself for complicated eyes.. long story. Have taken something like eighteen kinds of eye drops along the way, now down to 3. My 'badder' eye has a lazy lid (but that's both unusual and quite visible), and that's the one that gets the expensive drops, which can be irritating. Plus I live in Dryville, USA. So, my ophtho gave me a list for things to do re dry eyes -
1) immediate help, warm a washcloth with hot water, keep eyes closed, apply washcloth, helps but not all that long lasting.
2) eyedrops - a company called GenTeal, which sells 3 strengths. (Not sure he named a company, can't find the paper immediately). I tried the middle one, it helps. Naturally the third strength is even more money.
3) flax seed and/or fish oil in diet - well, I eat a lot of fish and I hate fish oil capsules, too damn big, though if I remember I sometimes break a capsule and add it to, say, mashed potatoes. Do have flax seed in the cabinet, at rest, as it were.
Meantime, it's surgery day for the IZ...