The eye-rubbing behavior of babies is basically taken as a sign that these little humans are ready to take a nap. But why exactly is this the case?
Babies Rubbing Their Eyes
The unfortunate news is that babies cannot directly be asked why they engage in such behavior, as noted by Dr. Rebecca Dudovitz, who is a general pediatrics associate professor from the UCLA David Geffen School of Medicine.
Dr. Dudovitz explains that it is known from human experience that it is a tendency of people to rub their eyes when they feel tired. This could be due to the uncomfortable feeling one may get when the muscles of the eyes have been working hard and need a break.
A Remedy For Tired Eyes
Similar to how a shoulder massage could be helpful after sitting on a desk for the whole day, muscles that could aid with eye focus could feel better after getting rubbed.
As for babies, they spend a lot of time looking at the objects that surround them. Their eyes also end up tired.
Staring can also leave the eyes dry. Since babies only blink a few times in a single minute, it is not shocking that their eyes also become dry. Ophthalmologist Dr. Robert W. Arnold from Alaska Children's Eye and Strabismus explains that more than being salt water, tears are mucus close to the surface, salt water at the middle layer, and an oil layer from the meibomian glands of the eyelid to prevent evaporation from happening. Hence, a tear that is healthy actually has three layers. Such a tri-layer needs to be renewed and smoothly spread across the surface through blinking.
When people face too much strong visual attention, blinking does not happen sufficiently. When blinking is not enough, this tri-layer could end up breaking apart and leaving dry patches over the cornea. In such a case, eye rubbing could serve as a reminder to blink more often.
A commonly cited reason for the good sensation one may feel when rubbing the eyes when tired is that the behavior could lower blood pressure through the stimulation of the vagus and trigeminal nerves. For some people, this could lead to a heart rate decrease of over 20% in a phenomenon called oculocardiac reflex.
However, Dr. Arnold questions such explanations. The doctor notes that there is no clear reason why a child may feel better when their heart rate is slowed down.
Oculocardiac reflex can also lead to life-threatening outcomes, such as cardiac arrest or bradycardia, which refers to when heart rate does not exceed 60 bpm.
Dr. Arnold explains that purposeful oculocardiac reflex stimulation can explain why children engage in such eye-rubbing behavior. Rather, it could result from excessive eye-rubbing.
However, most likely, babies could be rubbing their eyes for similar reasons as adults. Their eyes could feel dry and tired, and they could be ready to take a nap.
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