Redness in the eyes is a very common phenomenon in daily life and can occur in people of all ages, whether they are children, adolescents, or the elderly. There are many causes of redness in the eyes, both physiological and pathological. The physiological causes are mainly related to the individual’s physical condition and living and working habits, and the surrounding environment. If you stay up late, use your eyes at close range for a long time, contact electronic products for a long time, smoke and drink a lot, you will have red bloodshot eyes. Some people have red bloodshot eyes because of the surrounding environment, such as the surrounding environment is relatively unhygienic, and need to stay in this environment for a long time, the phenomenon of red bloodshot eyes will occur. Redness in the eyes can also be caused by strong light exposure, such as ultraviolet light, welding light, etc. Pathological causes are mainly caused by organic eye lesions. Some organic lesions of the eye include infectious inflammation and allergic inflammation, conjunctivitis, keratitis, iridocyclitis, etc. In short, there are many conditions that can cause redness in the eyes, no matter what the cause is, the main reason is that the eye is rich in blood vessels, causing local tissue congestion and edema.