Human Night Vision-Why Humans Do Not Have Night Vision?


As we are aware, mostly, the animals are capable of viewing through the darkness, but the humans do not have the same capacity, unlike the animals. Humans have many wonderful abilities that are not present in the animals. Why do we lack this night vision capacity? Look at the article below to know the answer in detail.

human night vision

How Is Tapetum Lucidum Related To Lack Of Human Night Vision?

Tapetum lucidum is a tissue layer that is present in most of the animals behind the eye. This helps in effective light reflection and increase the light availability for capturing. This is the reason why most animals that are nocturnal have a clear vision in the dark environment. Due to the absence of this layer, the humans, and the monkeys don not have the capacity to see through the darkness.

Light Sensitive Organs, What Are They?

Lack of this capacity in humans is due to the sensitivity of the eye and the adaptation to the darkness. This can be understood only by knowing the light sensitive organs and their functions.

In humans, the light can be sensed with the help of the light- sensitive organs that are located behind our eyes. They are of two types and are known as rods and cones. The primary function of these organs is to collect and send light impulses to the brain; the cones are useful for vision in the day time and the rods are those that are useful for the night vision.

Are They Sensitive To Color?

Yes, the rods and cones are both sensitive to colors. However, the sensitivities of them differ according to the visible wavelength of the colors, however, when under dark lighting conditions, the color is lost.

In general, the rods are more sensitive to blue to green lights when compared to the red lights. As the rods are responsible for enabling night vision, the light supposed to be used at the night time is the red colored one that is not bright.

How To Overcome A Blind Spot During Night Vision?

The center of the eye consists of a number of cones and does not show the presence of rods that are responsible for night vision. Therefore in the dark light situations that are about 50% of the moonlight conditions, there exist a blind spot in the center. Hence, when you require seeing in the lighting conditions that are below 50% of the moonlighting conditions, it is better to look at the position that has the highest sensitivity of the rods to enable in identifying the target in dark.

Hence, the lack of the tissue layer along with the sensitivity of the eye and the reduced capacity to adapt to the darkness are the factors that cause lack of night vision in humans.