What type of radiant energy can be seen and may cause permanent blindness?

The correct choice is visible radiant energy, which refers to the portion of the electromagnetic spectrum that is perceptible to the human eye. This type of energy is what allows us to see the world around us. When it comes to the risk of permanent blindness, exposure to intense visible light, especially from sources such as lasers or high-intensity lamps, can damage the retina and lead to irreversible vision loss.

While ultraviolet radiant energy can also cause serious eye damage, such as photokeratitis or cataracts, it is not visible to the human eye. Infrared radiant energy, likewise, is not visible and primarily associated with heat rather than damaging vision. X-ray radiant energy, although a form of high-energy radiation that can affect biological tissues, is also not part of the visible spectrum. In summary, visible radiant energy is the type that we can see and poses a risk of permanent blindness under certain conditions.