You have a hard time picking out stationary objects from any background. For every level of this disadvantage, you have a -1 to vision rolls to notice details or items that are not moving, to a maximum of -10. This penalty applies to Forensics, Observation, Tracking, and Search rolls to spot clues or hidden objects. The penalty also applies to rolls to identify objects whether or not they are moving rather than just noticing them. At level 10, you litterally cannot see things that do not move. At any level less than 10, you can see well enough for basic navigation.
Exception - if you have another discriminatory sense that could reasonably compensate (such as discriminatory smell when tracking), the total modifier of the Motion Sensitive vision penalty and the alternate discriminatory sense bonus will not give a penalty. At this point, you are relying on your other sense rather than sight.
Some level of this advantage is normal for all animals other than primates and birds. Animals with significant levels of this advantage usually have other senses for identifying objects, and just use sight to alert them that something is there.