An eye primer or base is a product that is applied to the eyelids before eyeshadow, eyeliner, or mascara to create a smooth, even surface and help the makeup last longer. Here are some common types of eye primers and bases:

1. Silicone-based primers: These types of primers create a smooth, matte base that helps to fill in any fine lines or wrinkles on the eyelids. They can also help to prevent creasing and smudging of eyeshadow.

2. Cream-based primers: Cream-based primers are typically thicker and more moisturizing than silicone-based primers. They can help to hydrate and smooth the eyelids, creating a more even surface for eyeshadow application.

3. Tinted primers: Tinted primers can help to even out skin tone on the eyelids and provide a base color for eyeshadow. They come in a variety of shades, from neutral to bright and bold.

4. Eyeshadow primers: Some eyeshadows come with built-in primers that help to prevent creasing and improve color payoff. These primers are typically clear or nude-colored and can be applied directly to the eyelids before eyeshadow.

Overall, using an eye primer or base can help to improve the performance and longevity of eye makeup. By choosing the right type of primer or base for your needs and skin type, you can achieve a flawless, long-lasting eye look.