How red eyes are caused - the science behind it(눈 충혈이 일어나는 이유)

<written on 19.03.17>

Red eyes(bloodshot eyes) happen by various reasons - from allergies to even exposure to sunlight. A list of these causes are: 

• allergies
• dry air/dust
• too much exposure to sunlight
• gas substance in the air (gasoline, etc)
• chemical substances
• smoke/flue gas

All of these can be harmful to your eyes and cause inflammation. In order to prevent or stop inflamation, your body causes vasodilation of blood vessels in the eye. Vasodilation is the expansion of blood vessels, which is the opposite of vasoconstrition.  Both phenomenons are caused by a type of hormone named vasopresssin. Vasopressin is used to contract blood vessels. Vasodilation occurs when the amount of vasopressin is no much, and when a substance called nitric oxide is created. Nitric oxide combines with soft muscle tissues and sends intracellular signals that make muscles relax, leading to expanding blood vessels.

https://en.wikipedia.org/wiki/Vasodilation

 

When vasodilation happens, blood flow to that part and the vascular permeability of blood vessels increase. Vascular permeability characterizes the capacity of a blood vessel wall to allow for the flow of small molecules or even whole cells in and out of the vessel. These factors enable more immune cells to arrive quicker at the inflamation site.

 

 

more about vascular permiability: https://en.wikipedia.org/wiki/Vascular_permeability

Vascular permeability - Wikipedia