The patient’s left corner of the eye especially red may be conjunctivitis, blepharitis and other diseases caused by. 1. Conjunctivitis: the conjunctiva covers the surface of the eye, rich in vascular system, when the patient’s conjunctival tissue is infected by bacteria, viruses and other germs, causing conjunctivitis, under the stimulation of inflammation, the patient may appear conjunctival congestion, photophobia, tearing and other discomforts, so the patient’s corner of the eye redness in the performance. 2. Blepharitis: The eyelid margins of patients are easily infected by bacteria, fungi and other germs, leading to blepharitis, which can cause redness at the corners of the eyes. In addition, if the patient is exposed to allergens, allergic blepharitis will occur, and the patient will also appear redness at the corners of the eyes, but also the symptoms of itchy eyes. It is recommended that patients with significant redness at the corners of their eyes seek prompt medical attention to evaluate their condition and treat it under the guidance of a physician.