วันพฤหัสบดีที่ 9 เมษายน พ.ศ. 2569

Ptosis (Blepharoptosis)

Ptosis (Blepharoptosis)

🔹 Definition

  • Ptosis = upper eyelid drooping จากความผิดปกติของกลไกยก eyelid
  • อาจเป็น sign ของ neurologic disease รุนแรง
  • ถ้าบัง visual axis functional disability

🔹 Anatomy (high-yield)

  • Levator palpebrae superioris (CN III) main elevator
  • Müller’s muscle (sympathetic) ยกเพิ่ม ~1–2 mm
  • Orbicularis oculi (CN VII) ปิดตา

🔹 Key measurements

  • MRD1 (margin reflex distance 1) = 4–5 mm (สำคัญสุด) จาก central light reflex to upper lid margin
  • Palpebral fissure (PF) = 9–12 mm
  • Levator function (LF)
    • 12 mm = normal
    • = myogenic / neurogenic / NMJ

🔹 Clinical approach

🧾 History (key questions)

  • congenital vs acquired
  • acute vs progressive
  • fluctuating? ( MG)
  • diplopia / headache ( neuro)
  • trauma / surgery / contact lens
  • family history

🔍 Examination

1.       Look

o   chin-up posture, eyebrow elevation

2.       Measure

o   MRD1, PF, lid crease

3.       Levator function

4.       Pupil

o   mydriasis CN III

o   miosis Horner

5.       EOM

6.       Fatigability test

o   sustained upgaze (> 1 min) / Cogan lid twitch MG


🔴 Red flags (ต้องรีบ evaluate)

  • ptosis + diplopia / ophthalmoplegia
  • ptosis + anisocoria
  • acute onset
    👉 suspect CN III palsy / Horner / intracranial lesion

🔹 Etiology (high-yield classification)

1. Congenital

  • levator dysgenesis
  • unilateral > bilateral
  • levator function
  • risk: amblyopia / strabismus

2. Aponeurotic (most common in adults)

  • levator aponeurosis dehiscence (เอ็นยึดเปลือกตาหย่อน)
  • LF normal
  • high lid crease
  • cause:
    • aging (involutional)
    • contact lens
    • post-op / trauma

3. Mechanical

  • eyelid mass / edema / tumor
  • dermatochalasis
    👉 heavy lid ptosis

4. Neurogenic

🧠 CN III palsy

  • ptosis + ophthalmoplegia ± dilated pupil
  • emergency rule out aneurysm

🧠 Horner syndrome

  • triad:
    • mild ptosis (1–2 mm)
    • miosis
    • anhidrosis
  • anisocoria in dark

5. Neuromuscular junction

Myasthenia gravis

  • hallmark = fluctuating + fatigable
  • ± diplopia
  • Cogan lid twitch, ice pack test positive

6. Myogenic

  • mitochondrial myopathy (CPEO)
  • myotonic dystrophy
  • OPMD
    👉 bilateral progressive + EOM involvement

7. Pseudoptosis

  • enophthalmos
  • hypotropia
  • contralateral lid retraction
  • dermatochalasis

🔹 Diagnosis

  • clinical เป็นหลัก
  • imaging เฉพาะ:
    • CN III palsy
    • Horner syndrome
      👉 หา underlying cause

🔹 Management

1. Treat underlying cause

  • MG medical therapy
  • Horner treat cause ± apraclonidine
  • botox-induced observation

2. Medical (selected cases)

  • Oxymetazoline eye drops
    • Müller muscle tone
    • MRD1 ~1 mm
  • eyelid crutch (temporary)

3. Surgery (mainstay)

Indications

  • visual axis obstruction
  • cosmetic concern

Type

  • good LF levator advancement
  • mild ptosis Müllerectomy
  • poor LF frontalis sling

⚠️ Complications

  • lagophthalmos exposure keratopathy
  • asymmetry / under- or overcorrection

🔹 Clinical pearls (ใช้จริงใน ER/clinic)

  • ptosis + dilated pupil = aneurysm until proven otherwise
  • ptosis fluctuating = think MG
  • ptosis + miosis = Horner
  • LF normal + high crease = aponeurotic (most common)
  • bilateral progressive + EOM myopathy

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