Certain tints are available dependent on the type of contact lens. Most lenses will have a light blue handling tint, so that they're easy to see while inserting and removing.
Hard contact lenses will have a dot to indicate the right eye.
And soft contact lenses are available in colored options to either enhance or cover the patient's natural iris color. This mainly serves a purpose as a cosmetic option, but are also available with and without a prescription.
Transition lenses are the newest introduction to the colored lens options. This provides the patient with UV protection as the lens darkens when the patient is outdoors.
Some lenses are created for prosthetic purposes, so the lens may either have a pupil or an iris painted onto the lens. You will primarily see this option in hard lenses.