All bat species can actually see, although at varying levels. Not all bats even use echolocation to find food – fruit bats typically use their nose to locate fruit.
Another common belief is that they can see only at night.
In fact, scientists at the Max Planck Institute found that the retinas of fruit bats also contain cone photoreceptor cells, which detect color and are located mainly in the center of the retina. The cones are not very sensitive to light, so they are typically used for day (or "photopic") vision.
The 2007 study disproved earlier claims that bat eyes contained only rod cells, which are located mainly on the edge of the retina and are responsible for night and peripheral vision. Cone cells also have a higher level of visual acuity than rods – that is, they are more helpful in the sharpness of vision than rods.