Ptosis
🔍 Definition
Ptosis is the abnormal drooping of the upper eyelid, either unilateral or bilateral, due to weakness or dysfunction of the muscles that elevate the eyelid — primarily the levator palpebrae superioris and Müller’s muscle.
🧠 In simple terms: the upper lid sags lower than normal — possibly covering the pupil and affecting vision.
🧬 Etiology – Types of Ptosis
Ptosis is classified based on cause:
1. Congenital Ptosis
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Present at birth
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Due to dysgenesis of the levator muscle
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Commonly unilateral
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Poor levator function (<4 mm)
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Associations: Amblyopia, strabismus, Marcus Gunn jaw-winking
2. Acquired Ptosis
| Type | Cause / Example |
|---|---|
| Aponeurotic (Involutional) | Levator aponeurosis disinsertion (e.g., aging, trauma, long-term contact lens use) – most common acquired |
| Neurogenic | Nerve problem (e.g., CN III palsy, Horner’s syndrome) |
| Myogenic | Muscle disorders (e.g., myasthenia gravis, muscular dystrophy) |
| Mechanical | Mass or edema weighing down lid (e.g., tumor, inflammation) |
| Traumatic | Injury to levator or nerve |
🧪 Clinical Features
| Feature | Description |
|---|---|
| Low upper eyelid margin | May partially or completely cover pupil |
| Asymmetry | Often visible even in primary gaze |
| Frontalis overaction | Eyebrows raised to compensate |
| Chin-up posture | To see better if vision is obstructed |
| Marcus Gunn jaw-winking | Lid moves with jaw (in some congenital cases) |
| Pupil abnormalities | In neurogenic causes (e.g., dilated pupil in CN III palsy, miosis in Horner’s) |
📏 Evaluation & Measurements
| Test | Purpose |
|---|---|
| MRD-1 (Marginal Reflex Distance 1) | Distance from corneal light reflex to upper lid margin (normal ≈ 4–5 mm) |
| Levator function test | Measures excursion of upper lid (normal > 12 mm) |
| Fatigue test / Ice pack test | In suspected myasthenia gravis |
| Pupil & eye movement exam | To rule out CN III palsy or Horner’s |
💊 Management
🔹 Treat the Cause
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Myasthenia gravis → Anticholinesterase drugs, immunosuppressants
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CN III palsy / Horner’s → Neuroimaging to rule out aneurysm, tumor, etc.
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Mechanical → Remove or treat the lesion
🔹 Surgical Management (Mainstay for Structural Ptosis)
| Surgery | Indication |
|---|---|
| Levator resection | Good levator function (>4 mm) |
| Frontalis sling | Poor levator function (<4 mm) – uses forehead muscle |
| Müller’s muscle-conjunctival resection | Mild ptosis, good response to phenylephrine |
| Aponeurotic repair | For aponeurotic (involutional) ptosis |
⚠️ Complications if Untreated
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Amblyopia (lazy eye) – especially in children
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Visual field defect
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Cosmetic concern
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Neck strain due to chin-up posture
🧠 Mnemonic: "PAINT" the Ptosis
| Letter | Cause Type | Example |
|---|---|---|
| P | Pseudoptosis | Enophthalmos, dermatochalasis |
| A | Aponeurotic | Aging, contact lens use |
| I | Involutional | Age-related muscle stretching |
| N | Neurogenic | CN III palsy, Horner’s |
| T | Traumatic | Lid or orbital injury |
📋 Quick Summary Table
| Feature | Ptosis |
|---|---|
| Definition | Drooping of upper eyelid |
| Most common acquired | Aponeurotic (age-related) |
| Most common congenital | Levator dysgenesis |
| Key symptoms | Lid droop, chin-up head posture, eyebrow lifting |
| Main treatment | Surgical correction (type depends on levator function) |
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