They usually have eight eyes equipped with lenses. This distinguishes them from insects that have compound eyes. Most spiders' eyesight is not particularly well developed.

An excerpt from the article 28 facts about spiders

However, this is not a rule, as there are families of spiders with six (Haplogynae), four (Tetrablemma), or two (Caponiidae). There are also species of spiders that do not have eyes at all. Some pairs of eyes are more developed than others and serve different purposes, for example, the primary eyes of jumping spiders are capable of color vision.