Night vision goggles work by accumulating what little amount of light is available and expanding it so that the naked eye can see it. Infrared is a new technology engaged with night vision goggles. Infrared goggles depend upon infrared waves that are emitted by anything that releases heat.
The difference in the temperatures between objects provides the contrast to distinguish between different things. Because night vision goggles magnify available light that bounces off something, no light indicates no magnified image. Since infrared goggles do not depend on ambient light, they do not pose the same problem.