What Is Ptosis?

Ptosis (from the Greek word for "falling") refers to a drooping upper eyelid that sits lower than its normal position. While mild ptosis may be purely cosmetic, moderate to severe ptosis can obstruct the visual axis and impair daily activities. It is distinct from dermatochalasis (excess skin), though both conditions frequently coexist.

Types and Causes

Aponeurotic (involutional) ptosis

The most common form in adults. Aging or repeated mechanical stress (contact lens wear, eye rubbing) causes the levator aponeurosis to stretch or dehisce from the tarsal plate. Levator function is usually preserved.

Congenital ptosis

Present at birth due to a developmental abnormality of the levator muscle itself. The muscle fibers are partly replaced by fibrous tissue, reducing both contraction and relaxation. Levator function is typically poor.

Neurogenic ptosis

Caused by a neurological deficit affecting the oculomotor nerve (third nerve palsy) or sympathetic pathway (Horner syndrome). Identifying the underlying cause is critical before surgical planning.

Myogenic ptosis

Associated with muscular disorders such as myasthenia gravis, myotonic dystrophy, or chronic progressive external ophthalmoplegia. Systemic evaluation is necessary.

Mechanical ptosis

Caused by a mass (tumor, cyst) or scarring that weighs down or tethers the eyelid. Addressing the underlying lesion is the primary treatment.

Diagnosis

1. Margin-reflex distance (MRD1): The distance from the upper lid margin to the corneal light reflex. Normal is approximately 4 mm; values below 2 mm indicate significant ptosis.
2. Levator function:Measured as the total excursion of the upper lid from downgaze to upgaze while blocking the brow. Good function (>10 mm) suggests aponeurotic etiology; poor function (<5 mm) suggests congenital or myogenic causes.
3. Palpebral fissure height: Comparison between the two eyes documents asymmetry.
4. Phenylephrine test: Topical sympathomimetic drops can temporarily raise the lid, helping predict surgical outcome with Muller muscle-conjunctival resection.
5. Systemic workup: When neurogenic or myogenic ptosis is suspected, neuroimaging, anti-acetylcholine receptor antibodies, or other investigations may be warranted.

Surgical Treatment

Levator advancement or resection

The standard procedure for aponeurotic ptosis. The levator aponeurosis is reattached or shortened to elevate the lid margin. Intraoperative lid height adjustment is performed with the patient awake and seated.

Muller muscle-conjunctival resection (MMCR)

A posterior approach suitable for mild ptosis with good levator function and a positive phenylephrine test. No external incision is required.

Frontalis sling

Reserved for severe ptosis with poor levator function (typically congenital). A sling connects the lid to the frontalis (brow) muscle, using the brow to raise the lid.

Recovery