What are the steps to perform a physical examination to test for ptosis in a patient?

Physical Examination for Ptosis

The physical examination for ptosis must begin with urgent assessment of pupillary responses in bright and dim lighting to identify life-threatening third nerve palsy with pupillary involvement, which represents a neurosurgical emergency such as a posterior communicating artery aneurysm. 1

Step 1: Pupillary Examination (MOST CRITICAL)

• Assess for anisocoria and pupil reactivity in both bright and dim illumination to distinguish between urgent and non-urgent causes 2, 1
• Dilated pupil with ptosis = third nerve palsy with pupillary involvement requiring immediate neuroimaging (MRI with gadolinium and MR angiography or CT angiography) 1
• Miosis (small pupil) with mild ptosis = Horner syndrome, indicating disruption of the sympathetic pathway that requires evaluation for carotid dissection 1, 3
• Normal pupil with complete ptosis and ophthalmoplegia = pupil-sparing third nerve palsy, typically microvascular from diabetes, hypertension, or hyperlipidemia 1

Step 2: Assess for Variability and Fatigability

• Observe ptosis with prolonged upgaze (sustained upward gaze for 30-60 seconds) to detect fatigable weakness characteristic of myasthenia gravis 4, 1
• Look for Cogan lid-twitch sign: after downward gaze, rapid upward saccade produces brief overshoot of the eyelid followed by ptosis 4
• Variable ptosis that worsens with fatigue and improves with rest strongly suggests myasthenia gravis 4, 3

Step 3: Ice Pack Test

• Apply an ice pack over closed eyes for 2 minutes 4, 2, 1
• Reduction of ptosis by approximately 2 mm is highly specific for myasthenia gravis 2, 1
• This test should be performed even in pediatric patients when myasthenia is suspected 2

Step 4: Extraocular Motility Assessment

• Test all extraocular movements to identify ophthalmoplegia, which when present with ptosis indicates third nerve palsy or other cranial neuropathies 1
• Isolated ptosis without ophthalmoplegia narrows the differential but does not exclude serious pathology 1

Step 5: Levator Function Measurement

• Measure levator muscle strength by assessing the distance the upper eyelid travels from extreme downgaze to extreme upgaze while immobilizing the frontalis muscle 3, 5
• Normal levator function is 12-15 mm; this measurement helps classify ptosis severity and guides surgical planning 5

Step 6: Bell's Phenomenon

• Assess Bell's phenomenon (upward rotation of the globe with forced eyelid closure) 3
• Absence of Bell's phenomenon predicts risk of postoperative corneal exposure 3

Step 7: Neurological Examination

• Perform complete sensorimotor examination to detect associated neurological symptoms including ataxia, tremor, hemiplegia, or other cranial nerve palsies 1
• Assess for neck weakness or head drop, which with ptosis indicates generalized neuromuscular disease (myasthenia gravis or botulism) requiring ICU-level monitoring for respiratory failure 4
• Evaluate respiratory function including vital capacity and negative inspiratory force if myasthenia gravis or botulism is suspected 4

Step 8: Fundus Examination

• Perform funduscopic examination to evaluate for papilledema or optic atrophy, which may indicate life-threatening intracranial pathology 1

Critical Pitfalls to Avoid

• Missing pupil-involving third nerve palsy as a neurosurgical emergency can be fatal; always check pupils first 2, 1
• Overlooking myasthenia gravis due to variable presentation; maintain high suspicion and perform ice test even when symptoms fluctuate 2
• Failing to assess for Horner syndrome may miss carotid dissection, which requires urgent vascular imaging 1, 3
• In pediatric patients, failing to diagnose and treat amblyopia early can lead to permanently poor vision 2