What is photo damage primarily caused by?

Photo damage is primarily caused by light exposure, particularly ultraviolet (UV) light from the sun. This damage occurs when the skin or other biological tissues are overstimulated or harmed by intense or prolonged exposure to light, leading to reactive oxygen species (ROS) formation. These ROS can cause oxidative stress, ultimately damaging cellular DNA, proteins, and lipids. This is why methods of protection against photo damage, such as sunscreen and protective clothing, are crucial for maintaining skin health as they absorb or reflect harmful UV radiation, thereby minimizing its harmful effects.

The other options, while they may have their own negative effects on health and well-being, do not directly relate to the concept of photo damage in the same manner as light exposure does. High temperatures can contribute to skin damage but are not the primary cause of photo damage specifically, which is linked to specific wavelengths of light. Cameras, while they can capture images of light exposure effects, do not contribute to photo damage themselves, and poor diet influences health in many ways, but it does not directly attribute to the damage caused by light.