Traumatic eye injuries that cause the pupil to become enlarged are usually caused by traumatic dilation or secondary glaucoma. When the eye is traumatized, the impact of a large force may damage the pupillary sphincter inside the iris tissue or the branch of the arterio-ocular nerve that innervates the movement of the pupillary sphincter, causing traumatic dilatation, which results in dilation of the pupil and the appearance of symptoms such as photophobia and glaucoma. Ocular trauma that damages the trabecular meshwork, the angle of the eye and other structures may cause secondary glaucoma. High intraocular pressure can cause the blood vessels inside the iris tissue to be compressed, which can also cause the pupil to contract with insufficient force, resulting in pupil dilation. Patients should go to the ophthalmology department of the hospital in time, and the doctor will diagnose the specific cause through detailed examination, and then only take targeted treatment to eliminate the symptoms.