Robots can help humans explore regions unknown, go into places too dangerous to tread, get a view at the tiny areas of the body, and more. Where robots do not see shadow, they can transmit camera taken pictures and video to human operators and perform vital tasks that would be to dangerous for humans to do directly.
Robotic vision as a self used sense is fairly new. These use a combination of cameras and lighting coupled with software that can take the visual data and translate it into commands for movement. While this type of technology is currently being adapted to industrial uses, it should be kept in mind that this kind of three dimensional sight ability can help robots become more self guided in complex situations like search and rescue, or exploration that ultimately help their human operators see things they would not otherwise be able to.
The most exciting applications for improved vision on robots is the ability to use different wavelengths to see different kinds of things. Where smoke or heat is a problem, like in fire based search and rescue, a robot that has UV range vision can clearly see and transmit information about its progress. Once the improved vision abilities become more standard, the a robot faced with changing conditions, like that of a burning building, would be able to make adjustments in order to keep searching for what it was programed to look for.
Additionally, using infrared vision would allow military based robots to make hits with precision that humans would be unable to do, from recon type work to bombing. What is even more exciting is that these robots should be able to make adjustments based on their vision to ensure that the correct targets are reached and should be less prone to being fooled then a human alone would be. In the Middle East robots were doing at least ten missions a day for the military.
Perhaps more useful and exciting is the looming possibility that robots can be used to assist the elderly and disabled. While still years off, such a thing as a guide robot for the blind, or helper robots for other tasks could be very useful.
What might be the most exciting way robots help improve human vision however is the exploration of space and underwater areas. These kinds of applications opens up the way for new discoveries and additional knowledge.