Ptosis

Ptosis - Lid Liftoff Lowdown

• Definition: Upper eyelid margin abnormally low.
  • Covers >2mm of superior cornea.
  • Or >1mm lower than contralateral lid.
• Normal Values:
  • MRD1 (Margin-Reflex Distance 1): 4-4.5mm.
  • Palpebral Fissure Height (PFH): 9-12mm.
• Key Elevators & Innervation:
  • Levator Palpebrae Superioris (LPS): CN III (Oculomotor); primary.
  • Müller’s Muscle: Sympathetic nerves; maintains 1-2mm tonic elevation.
  • Frontalis Muscle: CN VII (Facial); accessory, used in severe cases.

⭐ Myogenic ptosis is the most common acquired type, often due to levator dehiscence or dysgenesis (aponeurotic ptosis).

Ptosis - Droop Snoops

Upper eyelid droop with Margin Reflex Distance 1 (MRD1) < 2 mm or >2 mm asymmetry.

⭐ Myasthenia Gravis ptosis: characteristically worsens with sustained upgaze (fatigability) and improves with rest or ice pack test. Cogan's lid twitch may be present.

Ptosis - Eye Spy Sag

• History: Onset (congenital/acquired), duration, variability (myasthenia), trauma, diplopia, family hx.
• Key Signs: ↓Palpebral fissure, chin-up posture, frontalis overaction, abnormal lid crease, pupil/motility changes.
• Measurements:
  • MRD1 (Margin-Reflex Distance 1): Corneal reflex to upper lid margin. Normal 4-4.5 mm.
    • Ptosis severity based on drop from normal: Mild (~2 mm), Mod (~3 mm), Severe (≥4 mm).
  • Levator Function (LF): Lid excursion (downgaze to upgaze, frontalis blocked).
    • Normal ≥15 mm; Good >8 mm; Fair 5-7 mm; Poor ≤4 mm.
• Specific Tests:
  • Phenylephrine Test (10%): Positive if lid elevates 1-2 mm (Müller's muscle function).
  • Bell's Phenomenon: Assesses corneal protection during blink/sleep.
  • Cogan's Lid Twitch / Ice Pack / Fatigability Tests: For myasthenia gravis.
  • Marcus Gunn Jaw-winking: Synkinetic ptosis evaluation.

⭐ A positive phenylephrine test (upper lid elevation of ~2mm) is a strong indicator for a good outcome with Müllerectomy for ptosis correction.

Ptosis - Uplift & Unfurl

• Definition: Abnormal drooping of the upper eyelid below its normal position.
• Key Measurements:
  • Margin-Reflex Distance 1 (MRD1): Distance from corneal light reflex to upper lid margin. Normal: 4-4.5 mm.
  • Levator Function (LF): Total eyelid excursion from extreme downgaze to upgaze.
    • Normal: >12-15 mm
    • Good: >8 mm
    • Fair: 5-7 mm
    • Poor: ≤4 mm
  • Palpebral Fissure Height (PFH): Vertical distance between upper and lower lid margins in primary gaze. Normal: 9-12 mm.
• Etiology:
  • Congenital: Simple, Blepharophimosis, Marcus Gunn Jaw-Winking.
  • Acquired: Aponeurotic (most common), Myogenic (e.g., Myasthenia Gravis), Neurogenic (e.g., CN III palsy, Horner's), Mechanical, Traumatic.

  ⭐ Horner's Syndrome triad: Miosis, Ptosis (mild, 1-2 mm), and Anhidrosis. Ptosis due to Müller's muscle paralysis.

• Surgical Approach Based on Levator Function:

• 📌 Surgical Options Reminder "FLiM":

  • Frontalis Sling
  • Levator Resection
  • Mullerectomy (Fasanella-Servat procedure for mild ptosis with good LF, targets Müller's muscle)

High‑Yield Points - ⚡ Biggest Takeaways

• Ptosis: Upper eyelid drooping; MRD1 < 2 mm is diagnostic (normal 4-4.5 mm).
• Congenital ptosis: Most common, levator dysgenesis, poor levator function (LF), lid lag.
• Aponeurotic ptosis: Most common acquired, good LF, high lid crease.
• Myasthenia Gravis: Variable ptosis, fatigue-induced, Cogan's lid twitch, ice test positive.
• Horner's syndrome: Mild ptosis (1-2 mm), miosis, anhydrosis.
• Surgery: LF >8 mm → Levator resection; LF <4 mm → Frontalis sling operation.