These are some of the many things I wonder in my spastic brain. If I were for some reason to go sightless, how would I know to apply makeup? I did a tiny bit of research. I credit http://visionware.org, and http://www.ehow.com as well as,http://www.afb.org in assisting me in my research. AFB.org is the American foundation for the blind. They really had great deal of information.
Visionware suggests that as a blind or sight impared person you find a family member or trusted friend to help you label your cosmetics in braille. This helps in identification. A blind person operates much as a sighted person, but with all their other senses heightened. As they prepare to apply cosmetics they should feel their face and become familiar with the canvas. When applying shadow use the brush and feel the hollow of your eye ball. As applying blush, count the the strokes you use to keep it even. The blind person has less fear approaching their eye with a mascara wand than a sighted person does because they are using feel rather than sight.
Ehow has 5 suggested steps to suggested to a newly blind person as you help them through learning how to apply cosmetics again. I will condense them
1. Become familiar with the contours of your face.
2. Use a brush as though you are doing art on your face, count the strokes of everything you do so that it matches.
3. Make sure you are applying makeup on a clear, moisturized surface. Use a headband to keep your hair out of the way and a towel to protect clothing.
4. Use a damp towel between each step of makeup, (eyes, cheeks ect) to wipe your hands and avoid making mistakes on your face or getting your clothes dirty.
5. As much as possible have someone check you progress until you get comfortable doing this on your own.
The American for the blind person groom tips are quite lengthy. I am just going to provide the link directly to the website. There are some amazing things that I'd have never thought of. I take so much for granted with my sight. It was very much an education to me finding out how much more work it takes to get ready when you can't see what you are doing.
I hope that this gave you an answer to your question if you ever wonder how this was done.
Have a beautiful day