Left eyeball pain is alert to acute conjunctivitis, glaucoma, iritis, uveitis and other causes. 1. Acute conjunctivitis: due to the appearance of a large number of follicles and papillae on the conjunctiva, it will grind the eyeball and have a foreign body sensation, which leads to the appearance of left eyeball pain. 2. Glaucoma: manifested by optic nerve atrophy, visual field defects, high intraocular pressure, closing of the atrial angle and other symptoms, which may lead to eyeball pain. 3. Iritis: patients with iritis are prone to left eyeball pain when pressing on the eye, and the pain is more obvious during acute attacks. 4. Uveitis: Toxins irritate the ciliary nerve endings, causing ciliary muscle spasm, which leads to left eyeball pain. Left eye pain should be timely consultation, clear cause, follow the doctor’s instructions for standardized treatment.