Diagnosing Ptosis

NYU Langone ophthalmologists diagnose ptosis, or droopy eyelid, by examining your eye. The role of the eyelid is to protect the eye from foreign objects or debris. The eyelid also spreads tears evenly over the surface of the eye to keep it moist.

The function of the levator muscle, which starts in the eye socket and extends down across the eyelid, is to lift the eyelid out of your line of vision. If the levator muscle malfunctions or is damaged, then the eyelid may droop, causing ptosis. 

Depending on the severity of ptosis, the eyelid may droop only slightly, or it may cover the pupil entirely. Ptosis can completely restrict your superior vision, which is the ability to see in the top part of your field of vision. Because of this, people with ptosis have to use their forehead muscles in order to see properly.


Ptosis can affect children and adults. This condition can be congenital, if the levator muscle does not properly develop in the womb. If left untreated, children with congenital ptosis may develop other visual disorders, such as amblyopia, which is commonly known as lazy eye, or astigmatism, a condition in which the cornea is not round and smooth but irregularly curved. This causes distortion or blurriness in both near and distance vision.

Aging may also contribute to the development of ptosis. The levator muscle, like other muscles in the body, may become stretched and worn from years of use. Other times, ptosis results from nerve or muscular disorders—such as myasthenia gravis or muscular dystrophy—that cause general muscle weakness. It can also be caused by a traumatic injury to the eyelid that damages the levator muscle. 

Medical History

When diagnosing ptosis, an NYU Langone ophthalmologist asks about your medical history and symptoms, including when these began and whether you have recently experienced any kind of injury or trauma to the eye area.

Because ptosis is sometimes linked to disorders that can be hereditary, like myasthenia gravis and muscular dystrophy, the doctor may also ask about your family history, as well as any recent changes in your health.

Comprehensive Eye Exam

The ophthalmologist performs a comprehensive eye exam to assess your overall eye health. To determine the quality of your vision and to see if ptosis is affecting it, your doctor may perform a visual field test, which evaluates your superior vision.

Your doctor also examines the pupils for abnormalities that can sometimes be present in people with ptosis, specifically in people who have ptosis caused by nerve weakness. Ophthalmologists also assess your eye muscle function by having you look in different directions. 

The degree of the eyelid droop is determined by measuring the marginal reflex distance, which is the distance between the center of the pupil and the edge of the upper lid. Your ophthalmologist may also examine the strength and function of the levator muscle by holding the frontalis muscle, which is located in the forehead, still. He or she then measures the distance the eyelid travels from when you’re gazing down to looking up. 

If your doctor suspects that your symptoms result from an underlying medical condition, he or she may perform blood testing or refer you to a neurologist, so that these conditions can be ruled out. 

Your ophthalmologist determines the type of ptosis based on your medical history and the results of the comprehensive eye exam the doctor may have performed. You may then be referred to an oculoplastic specialist—an ophthalmologist with advanced training in plastic surgery of the eyes and surrounding areas. 

Based on the diagnosis and severity of the ptosis, the oculoplastic specialist can help you determine whether surgery may be right for you.

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