The inability to open the eyes when the sun is a little stronger is photophobia, and there are many reasons for this: first, consider corneal disease caused by various causes, such as corneal edema and cloudiness, or corneal trauma resulting in significant defects in the corneal epithelium, and the symptoms of irritation. Secondly, other eye diseases cause it, such as conjunctivitis, iridocyclitis, glaucoma, etc. Some patients may be caused by congenital disorders, such as partial or total congenital iris defects in some patients. If the pupil is dilated for various reasons, the pupil cannot narrow when sunlight is shining, so photophobia can occur, such as after using dilating eye drops, after eye trauma, or after actinic nerve palsy. Finally, it may also be related to systemic diseases, such as trigeminal neuralgia, meningitis, subarachnoid hemorrhage, migraine, etc.