Drooping eyelids are classified as congenital or acquired, depending on the patient's age of presentation; Acquired drooping eyelids are generally divided into 5 types based on the cause.
Neurogenic: It is caused by defective neural stimulation of the levator muscle of the upper eyelid. For example, third nerve palsy, Horner syndrome, Marcus Gunn jaw winking syndrome, multiple sclerosis, etc.
Myogenic: Myopathy of the eyelid-elevator muscle or defect in its neuromuscular junction causes myogenic ptosis, including myasthenia gravis, ocular myopathy, simple congenital, blepharophimosis syndrome, etc.
Mechanical: The function of the eyelid muscle is impaired due to the influence of some abnormal external structures such as tumors, chalazion, foreign body, scar, etc.
Aponeurotic: Also known as age-related eyelid droop, it is caused by a defective levator aponeurosis due to aging, trauma, or complications from surgery.
Traumatic: Any direct or indirect trauma resulting in detachment of the eyelid-lifting muscle, muscle stiffness and scarring, eyelid tear or vascular occlusion, or orbital bone fracture can cause ptosis.
