What builds up in your eye at night to allow you to see?

The ability to see in low light conditions, such as at night, is primarily due to the presence of a pigment called rhodopsin, also known as visual purple. This pigment is located in the rod cells of the retina, which are responsible for night vision. When light hits the rod cells, rhodopsin undergoes a chemical change that initiates the phototransduction process, allowing us to perceive images in dark environments.

As the dark adaptation process occurs, rhodopsin levels increase in the rod cells, enhancing our sensitivity to light. In contrast, melanin is a pigment found in various tissues, including the eye, but it primarily functions to absorb excess light and protect the retina rather than facilitating night vision. Cones are photoreceptor cells that are responsible for color vision and function optimally in bright light, while rod cells contribute to low-light vision but rely on rhodopsin to perform their functions effectively. Therefore, the accumulation of rhodopsin in the rod cells is essential for our eyes to adjust to darkness and improve our ability to see in dim conditions.