Itchy left eye can be considered to be related to physiological factors as well as pathological factors, which may include eye diseases such as allergic conjunctivitis, blepharitis, or inverted eyelashes. 1. Physiological factors: In the case of prolonged use of electronic products, reading and other excessive use of the eyes can cause dry eyes, itchy eyes and other manifestations, at this time you need to take appropriate rest in order to alleviate the symptoms. 2. Allergic conjunctivitis: After the eyes are stimulated by allergens such as pollen, dust mites or animal hair, it causes allergic reaction of the conjunctiva, at this time, not only one eye is itchy, but both eyes can be involved at the same time, with itchy eyes, congested conjunctiva, and the manifestation of a foreign body sensation, burning sensation, and so on. 3. Blepharitis: when the eyelid margins have sebum overflow or localized oval dermatophyte parasites, and in the visual fatigue, malnutrition and other triggers can be blepharitis occurs, at this time, conscious of the eye itching, burning sensation or tingling, eyelid margins have congestion. 4. Inverted eyelashes: When there are inverted eyelashes, the direction of the eyelashes is abnormal, and the stimulation of the eyeballs can cause eye itching, discomfort and tearing and other manifestations. Frequent itching of the eyes, it is recommended to consult a doctor in a timely manner to clarify the cause of the disease, and then follow the doctor’s instructions on the cause of the symptomatic treatment.