Types of Ptosis
NYU Langone eye specialists commonly treat ptosis, an eye condition characterized by a droopiness of one or both of the upper eyelids. A weakening or malfunctioning of the levator muscle, which is responsible for lifting the eyelid, causes this condition.
In congenital ptosis, the levator muscle doesn’t develop properly in the womb, so the child is born with compromised or little levator muscle function. As a result, children born with ptosis often have limited superior field vision—which is the top part of your field of vision—and may tilt their heads back in order to try to see properly.
If left untreated, these children may develop other visual disorders, including amblyopia, commonly known as lazy eye. When a child whose sight is still developing has complete vision in one eye and incomplete vision in the other due to ptosis, the nerve pathways from the brain to the affected eye can begin to atrophy, or waste away. This results in a lazy eye, or underdeveloped vision in that eye.
Because untreated congenital ptosis can have negative effects on your child’s vision, experts may suggest surgical treatment at a young age to prevent any complications.
Five main types of acquired ptosis can develop throughout a lifetime. These include aponeurotic ptosis, which is the most common type. In this condition, the levator muscle of the eyelid becomes overstretched, usually due to aging. Excessive eye rubbing or eyelid pulling due to eye irritation or long-term contact lens use can also cause the condition.
Neurogenic ptosis occurs when there is a problem with the nerve pathway that controls movement of the eyelid muscles. Causes of neurogenic ptosis include myasthenia gravis, third nerve palsy, and Horner syndrome.
In myogenic ptosis, the levator muscle is weakened due to a systemic disorder that causes muscle weakness. These conditions may include chronic progressive external ophthalmoplegia and types of muscular dystrophy.
With mechanical ptosis, the eyelid is weighed down by excessive skin or a mass.
Traumatic ptosis is caused by an injury to the eyelid—either due to an accident or other eye trauma. This injury compromises or weakens the levator muscle.