The first thing to remember when searching for white eyeliner is pigmentation. Pigments are what give your cosmetics color. You need to ensure that your white eyeliner of choice has high pigmentation so it is visible and bright. In an interview with Marie Claire, professional and celebrity makeup artist Carly Giglio recommended that before you choose a white eyeliner, you test it out on the back of your hand to see how it looks against your skin tone. 

This process is also known as swatching. The second factor to remember as you narrow down your eyeliner options is texture. The best eyeliner is one with a creamy, blendable texture. Eyes are very sensitive, so a creamy eyeliner that goes on smoothly is best to avoid too much trouble during application. And if you use eyeliner in pencil form, Giglio suggests that you ensure it's blendable. That will make it easier for you to smudge the eyeliner after application.