Eyeliner is a cosmetic product used to define and accentuate the eyes. Applied along the lash lines or waterlines, it visually thickens lashes, changes the perceived shape or tilt of the eye, and completes looks ranging from subtle daily wear to dramatic. [1, 2, 3]

Eyeliners are tailored to different skill levels, textures, and application preferences:

• Pencil / Kohl: Creamy and waxy formulas that are beginner-friendly. Ideal for blending, smudging, and creating soft, smoky eyes. [1, 2, 3, 4, 5]

• Liquid: Comes with a fine brush for sharp, precise, and graphic eye looks (like a classic winged "cat-eye"). [1, 2]

• Pen / Felt-Tip: Features a felt tip with a flow-through mechanism, merging the control of a pencil with the sharp precision of a liquid liner. [1, 2, 3, 4]

• Gel: Thicker, highly pigmented formulas (often in pots) that set quickly to provide bold definition and long-lasting, smudge-proof wea