For painters, hand and fingers are as important as eyes. All the magic happens at the end of the arm.
For a long time, I went painting in both oil and pastel without any protection. One problem I noticed, especially with pastel, is that my fingers and nails began to dry out and crack after only a day or so. My fingers actually hurt when trying to paint. I tried using a barrier cream like Gloves in a Bottle, and although it does work, I didn't like the fact that in the field I couldn't thoroughly wash it off at snacktime. Who wants to peel and eat an orange with that stuff still on?
Long ago, I worked in restaurants. At one establishment, we had a bartender who wore finger cots during his shift. He said that squeezing lemons for drinks made his fingers crack otherwise. In retrospect and after with my experience with pastel, I am completely sympathetic. I try to make sure I have a little bag of finger cots in my backpack before I head out.
Finger cots come in different sizes and colors. Most pharmacies have them, and you can also get them online. If you're careful, you can also reuse them once or twice before they rip.
I paint with gloves, too. I prefer the nitrile gloves to the latex; latex can cause an allergic reaction in some people. But gloves do make my hands sweat. If I'm painting in pastel, I prefer the finger cots; if I'm painting in oil, I use the gloves. Although oil painting doesn't make my fingers dry out, some of the paints stain and some contain toxic metals that might be absorbed through cuts.
Remembering to wear gloves or finger cots takes discipline, of course.
You can find more helpful tips and tools in my book, Backpacker Painting: Outdoors with Oil & Pastel, available at Amazon from this link.