Levator Aponeurosis

• Origin: Lesser wing of the sphenoid

• Insertion: Orbicularis oculi, dermis, tarsus

• Innervation: Superior division of oculomotor nerve (CN III)

• Action: Provides 10-12 mm of eyelid elevation

• Embryology: Develops in the third gestational month from the superior rectus muscle

• Anterior lamella of the levator muscle forms aponeurosis

• Posterior lamella of the levator muscle forms Müller muscle

• Approximately 2-5 mm above the tarsus the anterior portion of the levator aponeurosis joins the orbital septum.

Müller Muscle

• Origin: Posterior lamella of levator muscle

• Insertion: Superior border of tarsus

• Innervation: Sympathetics

• Action: Provides 2-3 mm of eyelid elevation

Frontalis Muscle

• Origin: Galeal aponeurosis

• Insertion: Suprabrow dermis

• Innervation: Frontal branch of facial nerve

• Action: Elevates brow and upper eyelid skin

True Ptosis

• Intrinsic drooping of the affected eyelid

Pseudoptosis: Conditions That Mimic True Ptosis

• Grave disease: Retraction of contralateral lid can give appearance of ptosis on unaffected side

• Hypotropia: Downward rotation of the globe with accompanying lid movement

• Duane syndrome: Extraocular muscular fibrosis and globe retraction

• Posttraumatic enophthalmos

• Contralateral exophthalmos: Gives impression of ptosis on the unaffected side

• Chronic squinting from irritation

Congenital Ptosis

^{2 , 3}

• Developmental dysgenesis in the levator muscle

• Idiopathic persistent ptosis noticed shortly after birth

• Usually not progressive

• Signs confined to the affected eyelid(s)

• Decreased palpebral aperture with reduction of the pupil reflex to upper eyelid margin measurement (marginal reflex distance test [MRDI])

• Decreased levator excursion

  • Poor or absent levator function reflected in the absence of the supratarsal crease

• Ptotic eyelid generally higher than the normal eyelid during downgaze

• Inheritance pattern unclear

• Levator biopsies in congenital ptosis show absence of striated muscle fibers with fibrosis.

• Associated ocular abnormalities

  • Coexistent strabismus and amblyopia

    • Caused by pupil occlusion

  • Marcus Gunn jaw-winking syndrome

    • Synkinesis of upper lid with chewing

    • Seen in 2%-6% of congenital ptosis

    • Caused by aberrant innervation from fifth cranial nerve

  • Blepharophimosis syndrome

    • Triad of ptosis, telecanthus, and phimosis of lid fissure

  • Congenital anophthalmos or microphthalmos

    • Hypoplasia of the lids, globe, and orbital bones

  • Coexistent eyelid hamartoma

    • Neurofibromas

    • Hemangiomas

    • Lymphangiomas

Acquired Ptosis

^{2 , 3}

• Myogenic

  • Involutional myopathic (senile ptosis)

    • Most common type

    • Stretching of the levator aponeurosis attachments to the anterior tarsus

    • Dermal attachments are maintained and therefore the supratarsal crease rises.

    • Levator function is usually good.

  • Chronic progressive external ophthalmoplegia

    • Progressive muscular dystrophy affects the extraocular muscles and levator.

    • 5% of cases involve the facial and oropharyngeal muscles.

• Traumatic

  • Second most common type

  • Allow recovery of myoneural dysfunction, resolution of edema, and softening of scar (approximately 6 months).

  • This can occur after cataract surgery from dehiscence of levator aponeurosis.

• Neurogenic

  • Third nerve palsy: Paralyzes levator muscle

  • Horner syndrome: Paralyzes Müller muscle

  • Myasthenia gravis

    • Primarily, young women and old men are affected.

    • Ptosis worsens with fatigue, at the end of the day.

    • Improvement with neostigmine or edrophonium is characteristic.

• Mechanical

  • Upper lid tumors

  • Severe dermatochalasis (excessive upper lid skin), brow ptosis

Determination of Cause

• Congenital or acquired

Degree of Ptosis

(table 39-1)

• Always compare with contralateral side.

• Measure amount of descent over upper limbus.

  • 1-2 mm: Mild

  • 3 mm: Moderate

  • 4 mm or more: Severe

• Record palpebral fissure height.

Levator Function

(Table 39-2)

• Measure from extreme downward gaze to extreme upward gaze while immobilizing the brow.

• >10 mm: Good

• 5-10 mm: Fair

• <5 mm: Poor