Eye redness is the appearance of redness in the part of the eye that is exposed to the lid fissure, such as conjunctival congestion and bleeding under the conjunctiva. Red eyes are a perennial pain for many people, and the occasional red eyes make them feel uncomfortable as well as affect their appearance and make others look away. And regardless of the spring, summer, autumn and winter, there are a number of diseases that can cause eye redness, of course, not least many infectious eye diseases, we need to be extra vigilant. But how much do we know about eye redness? Are many of the things we think are “common knowledge” wrong? We often have a lot of misconceptions about eye redness: Misconception 1: Eye redness is inflammation, just order some eye medication yourself. Comment: Eye redness is divided into conjunctival congestion and bleeding, and conjunctival congestion is divided into several types, respectively, suggesting different eye diseases. Conjunctival congestion is mostly caused by inflammation, and there are many causes of inflammation, which need to be sorted out in detail for medication. Bleeding of the conjunctiva, on the other hand, does not require medication. Myth 2: Red eyes are red eyes. Comment: Red eyes do not necessarily mean “pink eye”. Many other eye diseases, such as iridocyclitis and acute angle-closure glaucoma, can also have symptoms of red eyes. If these diseases are mistaken for “pink eye” and the anti-inflammatory eye drops are ordered at home by themselves, it will delay the treatment and also cause serious consequences. Myth 3: If you have conjunctivitis or keratitis, you can buy anti-inflammatory drugs at the pharmacy to treat it yourself. Comment: Conjunctivitis and keratitis are complex and generally have several causes such as bacterial infections, viral infections, allergies and dry eyes. Most of the “anti-inflammatory drugs” available in pharmacies are antibiotic eye medications like chloramphenicol, which can only treat some bacterial infections, but more often we need antiviral, anti-allergy anti-inflammatory drugs and artificial tear drops, which are rarely available in pharmacies. How should we recognize eye redness in our daily life? Eye redness caused by various types of inflammation is often a manifestation of congestion, which is the expansion of blood vessels, so a closer look is a red color composed of a filament of red lines (blood vessels); while the redness caused by bleeding has no filamentous manifestation, which is a red-colored blood. The most common cause of eye redness is eye infection. Inflammation of the eyelid skin around the eye, inflammation of the lid margin, and mydriasis can cause eye redness, which is relatively easy to identify, and the eyelid will behave accordingly in addition to the eyeball portion. In addition, infectious inflammation of the conjunctiva and cornea can cause eye redness, which is often accompanied by eye discomfort, such as foreign body sensation and tingling, and eye discharge. In this case, you need to go to a hospital to determine the type of infection and apply sensitive antibiotics, antiviral drugs and even antifungal drugs, rather than buying drugs at the pharmacy yourself. Allergic inflammation can also cause eye redness. All kinds of foreign bodies entering the eyes can cause eye allergies. City dust, car exhaust, spring pollen, etc. are all common causes of allergies. Allergic inflammation is mainly caused by itchy eyes, or in severe cases, red, swollen and itchy eyelids, and often accompanied by itchy nose, sneezing and other signs of allergic rhinitis. At this time if treated with antibiotic eye drops may cause the allergy to worsen. Therefore, if you have itchy eyes, itchy nose, and sneezing in a fixed season every year, it is most likely caused by pollen or other allergens that appear at a specific time of the year, so you can treat it with anti-allergy eye drops as a preventive measure every year. Otherwise, you should go to the hospital and let a professional doctor make a judgment. Subconjunctival hemorrhage can also cause eye redness, and it can expand rapidly and have a frightening appearance. However, no special treatment is actually needed for this type of eye redness. A cold compress in the early stages when the blood is still coming out, and a hot compress in the later stages to promote the absorption of the blood is sufficient. However, if such symptoms occur frequently, be alert to the presence of systemic vascular pathology, such as hypertension and atherosclerosis. Some other causes of eye redness are: progression of pterygium, foreign bodies in the conjunctival sac or cornea, physical or chemical burns, excessive eye use, alcohol consumption, and emotional stress. However, if a foreign body enters the eye and does not flow out with the tears, you may need to go to the hospital to remove the foreign body. Physical or chemical burns should be flushed with plenty of water in the field immediately before going to the hospital. It should be noted that some serious eye diseases can manifest as eye redness. For example, acute glaucoma can manifest as severe eye redness, and is often accompanied by eye pain, headache, vomiting, and iris vision. You need to go to the hospital immediately for emergency treatment, but don’t just order some eye drops on your own. Iridocyclitis is also characterized by redness in the early stages, sometimes accompanied by pain in the eye or photophobia and loss of vision. However, sometimes there is only redness and an unnoticeable loss of vision, which can have serious consequences if you do not go to the hospital in time. Eye redness may seem like a small thing, but if ignored, it can have serious consequences. For eye redness, we need to be more aware and pay more attention to it. Don’t be misled by the “common sense” that you think is too troublesome or costly or misguided to delay treatment.