Find a piece of birch bark, preferably six to eight inches long and four to six inches wide. This helps make sure that the bark is large enough to cover to your eyes and that the goggles will be large enough to wrap around your head fairly naturally.
Cut the bark into a rectangle shape, keeping it roughly the same size as recommended in Step 1.
Measure the distance between the centers of your eyes. This doesn't have to be exact, but you need this measurement to cut eye holes in the bark. You can use your fingers to measure the approximate length.
Use your knife to mark these points on the smooth side of the bark, and use these marks to cut eye holes. Cut slits into these measurements, not large holes. These should be small slits, maybe a quarter of an inch at the very most, and many people will make them even smaller.
Near the bottom of the bark, cut a triangle out to make room for your nose. Try these Eskimo goggles on. You don't need a large slit to see, and the smaller the slit, the fewer UV rays that can reflect into your eyes and cause damage such as sun blindness. Cut the triangle as needed so the mask rests on your nose and still lines your eyes up with the eye slits.
If necessary, you can carve Eskimo goggles from wood or
animal bone, but this takes much longer and is less practical than using birch bark. The technique remains the same.