Six surprising causes of red eyes, most notably stress and smoking
Dr. Mohamed Hantira _ Honorary Assistant Professor mentioned
Ophthalmology Department – Umm Al-Qura University _ Saudi Arabia 6 surprising causes of redness and blood congestion in the eye, and these reasons include the following:

Focusing a lot while working and looking for long periods at the computer screen or when using a mobile phone, this habit can cause dryness and eye irritation, which results in blood congestion in the eyes.
Seasonal allergies can cause red eyes, because there are some allergens present in the environment such as pollen that can lead to inflammation of blood vessels in the eyes.
Some medicines If you are taking some strong medicines such as anti-anxiety drugs and antibiotics, they can cause dry eyes, making them appear bloodshot.
Smoking can cause dry eyes, and lead to inflammation of the blood vessels in the eye, which causes the eyes to become infected with blood.
Swimming Some people may experience eye congestion with blood, especially after swimming, whether in swimming pools or the sea, as a result of exposure to chlorine and salts that result in irritation and congestion in the eyes.
Stress and tension can cause eye congestion, because stress increases blood flow to the brain and optic nerves.