How do you diagnose and manage a patient with suspected ptosis?

How to Check for Ptosis: A Structured Clinical Approach

Begin with four essential measurements at the bedside: palpebral fissure height, marginal reflex distance (MRD1), upper eyelid crease position, and levator function test to establish the diagnosis and severity of ptosis. 1

Initial Bedside Measurements

• Marginal reflex distance (MRD1): Measure the distance from the corneal light reflex to the upper eyelid margin with the patient looking straight ahead—this quantifies ptosis severity (normal is 4-5 mm). 1
• Palpebral fissure height: Measure the vertical distance between upper and lower lid margins—ptosis is minimal (1-2 mm reduction), moderate (3-4 mm), or severe (>4 mm, covering the pupil). 2, 1
• Levator function test: Have the patient look from extreme downgaze to extreme upgaze while you measure upper lid excursion with the brow immobilized—normal is 15+ mm, fair is 5-10 mm, poor is <5 mm. 3, 1
• Upper eyelid crease: Measure the distance from the lid margin to the crease—an elevated or absent crease suggests aponeurotic ptosis. 1

Critical Urgent Evaluations (Rule Out Emergencies First)

Pupillary Examination in Bright and Dim Light

• Check for anisocoria immediately: A dilated pupil with ptosis indicates third nerve palsy with pupillary involvement—this is a neurosurgical emergency requiring urgent neuroimaging (MRI with gadolinium and MR angiography or CT angiography) to rule out posterior communicating artery aneurysm. 4, 5
• Check for miosis with ptosis: Mild ptosis with a constricted pupil suggests Horner syndrome from sympathetic pathway disruption (consider carotid dissection until proven otherwise). 4, 6

Extraocular Motility Testing

• Assess all six cardinal positions of gaze: Complete ophthalmoplegia with ptosis and pupillary involvement requires immediate neuroimaging. 4, 5
• Pupil-sparing third nerve palsy: If there is complete ptosis with complete motor dysfunction but a normal pupil, the etiology is almost always microvascular secondary to diabetes, hypertension, or hyperlipidemia. 4

Specialized Testing for Specific Etiologies

Ice Test for Myasthenia Gravis

• Perform when ptosis is variable or fatigable: Have the patient look in sustained upgaze for 30-60 seconds to see if ptosis worsens, suggesting myasthenia gravis. 4, 5
• Apply ice pack test: Place an ice pack over closed eyes for 2 minutes—reduction of ptosis by approximately 2 mm is highly specific for myasthenia gravis. 7, 4

Complete Sensorimotor Examination

• Detect strabismus: Assess ocular alignment in all positions of gaze to identify associated neurological deficits. 4, 5
• Evaluate for associated neurological symptoms: Check for ataxia, tremor, hemiplegia, or involvement of fourth or sixth cranial nerves. 4

Fundus Examination

• Check for papilledema or optic atrophy: This rules out potentially life-threatening conditions causing increased intracranial pressure or compressive lesions. 4, 5

Slit-Lamp Examination

• Evaluate for mechanical causes: Perform detailed anterior segment examination for masses, inflammation, or floppy eyelid syndrome (upper eyelid easily everts). 5

Common Pitfalls to Avoid

• Missing pupil-involving third nerve palsy as a neurosurgical emergency: Always check pupils in bright and dim light—failure to recognize this can result in catastrophic outcomes from ruptured aneurysm. 7, 5
• Assuming microvascular etiology in pupil-sparing third nerve palsy without thorough evaluation: Even pupil-sparing cases require careful assessment and consideration of neuroimaging if other features are atypical. 5
• Overlooking myasthenia gravis due to variable presentation: Consider the ice test even when antibodies might be negative, as single-fiber EMG may still be diagnostic. 7, 5
• Failing to diagnose amblyopia early in congenital ptosis: In pediatric patients, delayed treatment can lead to permanently poor vision. 7
• Not recognizing daily variation in ptosis: Ask specifically about fluctuation throughout the day, which strongly suggests myasthenia gravis. 6

When to Order Neuroimaging

Urgent Neuroimaging (MRI with gadolinium and MR/CT angiography)

• Ptosis with pupillary involvement (dilated pupil). 4, 5

Elective Neuroimaging (MRI head and orbits with contrast)

• Ptosis with ophthalmoplegia, proptosis, or other neurological deficits. 7, 4
• Ptosis with associated neurological symptoms suggesting brainstem pathology. 5

Neuroimaging NOT Typically Required

• Isolated ptosis without other neurological symptoms, normal pupils, and normal extraocular motility does not warrant advanced neuroimaging as first-line investigation. 7, 5