Redness in the outer corner of the eye is usually due to the following causes: 1. due to eczema of the eyelid area, usually seen in patients with blocked tear ducts, impingement, chronic conjunctivitis, due to chronic tearing of the eye or long-term use of eye drops, thus irritating the skin in the outer corner of the eye and triggering a chronic allergic reaction, leading to local redness and even thickening, flaking, and ichthyotic changes of the skin. 2. due to blepharitis It is caused, in particular, by canthal blepharitis, which occurs in the outer corner of the eye and triggers localized redness and chapping of the skin, and is caused by Mo-Abis infection, and lack of vitamin B2 is a common cause of it. It is usually cured by regular treatment with antibiotic ointment, such as levofloxacin ointment.3 It can be caused by pigmentation in the corner of the eye, long-term use of eye drops, or chronic inflammatory stimulation in the corner of the eye.