Sleep is what many consider to be one of their favourite pastimes. It allows the mind to rest, while simultaneously alleviating loads of stress and countless worries that limit the body’s potential. Sleeping is also crucial for maintaining good health, and teenagers and young adults should be getting at least seven to eight hours of sleep a night. While the eyes are one of many body parts that rest while the body is in its recharging state, they also do much more than simply shut down while dozing off.
Firstly, when you sleep, your eyes are obviously closed. The eyelids are responsible for this important function, as it assists in protecting the eyes from foreign materials. Pathogens in the air can pretty easily enter your body through the eyes, and for the eyes to remain open overnight would be quite problematic, as being exposed results in potentially-harmful bacteria causing serious infections in the body. While the eyes are closed, they are still able to sense light, albeit at a limited capacity. This suggests why light is somewhat detectable even when closed, which further contributes to the function of waking up. By allowing light detection, the body naturally responds and is able to wake up to light, as the eyes are able to sense the presence of sunlight, therefore signaling the body to wake up.
During sleep, the eyes do not send any visual information to the brain, and it takes approximately thirty seconds for the connection between the eyes and the brain to fully reboot. This is why vision is often impaired when the body first wakes up.
The human body goes through 5 stages of sleep. The first 4 stages are considered Non-REM and the final stage is REM, also known as rapid eye movement. Almost 50 percent of the total time sleeping is spent during stage 2, while 20 percent is spent during REM and the remaining 30 percent is split between stages 1, 3, and 4.
During stage 1, the eyes roll very slowly and repeatedly open and close slightly. This occurs briefly after dozing off into a light sleep, allowing the body to easily be woken up. In the next 3 stages, however, the eyes are completely still, and the body enters a much deeper sleep. The REM stage, on the other hand, is much more exciting.
During REM sleep, the eyes move around rapidly under the eyelids, but still do not send any visual information to the brain, although scientists have discovered that the visual cortex is active during this time, the part of the brain that is responsible for processing visual data. This is because memory reinforcing occurs during REM sleep, and this function looks to integrate the experiences during the day into your memory. REM sleep is also when people dream.
After a long day, the body deserves the opportunity to rest, and as you drift off into dreamland, sleep gives the mind a necessary reset for what is to come.