Choosing the best waterproof mascara for sensitive eyes starts with checking the formula. Look for products labeled hypoallergenic, fragrance-free, and ophthalmologist-tested to reduce irritation risk. Avoid mascaras with heavy dyes or strong preservatives that may trigger discomfort. A lightweight, flexible waterproof formula helps prevent flaking and smudging while keeping lashes soft. Brush shape also matters — smaller or tapered wands offer better control and less contact with the waterline. Consider conditioning ingredients like panthenol or vitamin E for added lash care. Always patch test first and use a gentle remover to protect delicate eyes.