Pimeänäköön

Pimeänäkö, also known as night vision, refers to the ability of an organism to see in low-light conditions. This ability is not uniform across all species, with some animals possessing far superior night vision than humans.

The biological mechanisms behind pimeänäkö vary. Many nocturnal animals, such as cats, owls, and some insects, have adaptations that enhance their ability to detect light. These can include a higher density of rod cells in their retinas, which are more sensitive to light than cone cells, responsible for color vision and detail in bright light. Some animals also possess a tapetum lucidum, a reflective layer behind the retina that bounces light back through the photoreceptor cells, giving them a second chance to absorb the light. This is why many animals' eyes appear to glow when light shines on them in the dark.

Humans have a limited capacity for pimeänäkö. In very dim light, our vision relies primarily on rod cells. However, our rod cells are not as numerous or as sensitive as those of many nocturnal animals, and we lack a tapetum lucidum. Consequently, human vision in darkness is significantly impaired, and colors are not perceived.

Technological advancements have led to the development of artificial night vision devices. These devices typically amplify available ambient light or utilize infrared radiation to create an image visible to the human eye. These technologies are employed in various fields, including military operations, wildlife observation, and security.