What risk is associated with looking directly into a fiber optic cable?

Looking directly into a fiber optic cable poses a significant risk because it can expose the eyes to intense light that is not visible but carries a high potential for damage. An active fiber signal, which is transmitted through the optical fiber, consists of concentrated light signals—these can indeed burn the retina, leading to serious and possibly permanent vision impairment.

The intense, focused light that travels through the fiber is beyond the sensitivity of the human eye, which can result in damage before an individual is even aware of the danger. This risk is particularly concerning since fiber optics are used in numerous applications, including telecommunications and medical equipment, where the light can be powerful enough to cause harm without a direct visible warning.

In contrast, other options such as eye strain, temporary blindness, or color blindness do not accurately capture the specific danger associated with looking into an active fiber optic cable. While these may be valid concerns in different contexts, they do not represent the immediate and direct risk involved with fiber optic cables.