When your eyes itch, rub them; when your eyes are sore, rub them; when your eyes are tired, rub them. The matter of rubbing the eyes is ordinary for everyone, but you do not know that the small action of "rubbing" is harmful to the eyes.
The surface of the human eye has a natural protective layer - the tear film - which keeps the cornea and conjunctiva moist. Every time you blink your eyes, it is a process of replenishing the tear film.
When using the eyes for a long time, due to the high concentration, the blinking frequency becomes low, the tear film "refresh" frequency decreases, and tear evaporation accelerates, it will produce the feeling of dry eyes. Therefore, when we feel dry or itchy eyes, we will subconsciously rub our eyes.
The following pictures show the changes in the eye when people rub their eyes as captured by MRI.
You can see that the eyeball is constantly being squeezed deformation, ready to burst the feeling, but the person who rubs the eye is unaware. You may think that rubbing two is not a big deal and even slightly enjoyable, but I do not know that such behavior hurts the eyes because it may lead to eye deformation.
A characteristic feature of the cone cornea is a dilated central or paracentral cornea that thins and protrudes forward in a tapered shape, often resulting in a high degree of irregular astigmatism and a significant loss of vision in the late stages that can lead to blindness. Although the probability of occurrence is relatively tiny, studies have shown that eye rubbing significantly contributes to many eye injuries, especially cone corneas.
A normal cornea has just the right amount of curvature to allow us to see the world by working closely with other organs to gather light onto the retina. However, the cornea is very soft and can become distorted with the slightest rubbing. You may have experienced this: when you rub your eyes too hard, you experience a brief blurring of vision that takes a while to heal.
This is because when the cornea is deformed by rubbing, the light cannot be accurately focused on the retina, there is some dispersion and shift, and the degree of astigmatism increases for a short time so that the vision will be blurred. However, the cornea is flexible, and when it recovers, clear vision will be regained. However, if you rub it like this often, it may have a long-lasting effect on the shape of the cornea.
Compared to other parts of the body, the eyes are sensitive and delicate and are susceptible to various bacterial and viral infections. When you rub your eyes with unclean hands, you expose your eyes to more microorganisms, such as bacteria, viruses, and even allergens, which can lead to infectious or allergic conjunctivitis.
Therefore, we recommend not rubbing your eyes if you can. If you have to rub your hands, please wash your hands; gently press around the eyes, and do not use your dirty hands to rub hard.