I also have found that my eyes have become slightly sensitive over the last couple of years. I did a bit of research on this, and apparently it is common as some people get older. The skin on the eyelids can become thinner. You might want to consider seeing a dermatologist to determine what ingredients you are sensitive to. Otherwise, it can just be trial and error.
At the moment, I’m trialling eye pencils by INIKA. The pencils smudge to varying degrees and need to be set with eyeshadow or a clear setting powder. The worst for smudging is the black, so I can’t recommend that one. I have hooded eyes, so I only wear the pencils on my lower lash line. You can use the loose INIKA eyeshadows as eyeliners (or any other brand of natural mineral eyeshadows); and I’m going to experiment with this in the coming weeks.
I like the eyeliners by Mirenesse. Although they don’t contain all natural ingredients, their ingredients are slightly kinder to humans. The best way to try Mirenesse products is when they have a sale on their website.
You could also try Physician’s Formula, Jane Iredale and Eye of Horus products. I have just tried a black Eye of Horus pencil, and it did not smudge. I have a Jane Iredale eyeshadow palette that has a soft black eyeshadow – I sometimes use this as an eyeliner on my lower lash line.
There are lots of other natural brands of eyeliners that I could recommend, but I haven’t tried them all. You can find them in health food stores and online stores specialising in natural beauty products.