Corneal Trauma

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Introduction to Corneal Trauma - Eye's Shield Under Siege

The cornea, the eye's transparent "shield," is vital for vision and protection. Trauma to this structure is common and potentially sight-threatening.

  • Types of Corneal Injuries:

    • Mechanical:
      • Abrasions: Superficial epithelial defect.
      • Lacerations: Partial/full-thickness (penetrating/perforating).
      • Foreign Bodies: Superficial or intraocular.
      • Blunt Trauma: Contusion, globe rupture.
    • Non-Mechanical:
      • Chemical Burns: Acid/Alkali (⚠️ Alkali more severe).
      • Radiation Keratitis: e.g., UV exposure.
  • Common Patient Presentation:

    • Severe pain, foreign body sensation.
    • Photophobia, lacrimation.
    • Blurred vision.
    • Redness (circumciliary injection).
    • History of trauma.

⭐ Alkali chemical burns penetrate deeper into ocular tissues via saponification, causing more extensive damage than acid burns.

Corneal Trauma: Chemical Burn

Mechanical Corneal Injuries - When Things Go Bump (or Sharp!)

  • Common Types:
    • Corneal Abrasion: Superficial epithelial defect; intense pain.
    • Foreign Body (FB): Superficial/embedded; rust ring if metallic.
    • Laceration: Partial/full-thickness (penetrating/perforating).
  • Key Symptoms: Sudden pain, photophobia, lacrimation, FB sensation, ↓vision.
  • Essential Signs:
    • Fluorescein staining: Highlights epithelial defects (abrasions, entry sites).
    • Visible FB: On cornea or under lids (evert lids!).
    • Seidel's Test: Positive in perforation (aqueous leak dilutes fluorescein - "waterfall" sign).
    • Other: Conjunctival injection, AC reaction, hyphema, irregular pupil.
  • Management Principles:
    • Abrasion: Topical antibiotics, cycloplegic, analgesia. Patching controversial.
    • FB: Removal (needle/spud), rust ring removal (burr), antibiotics.
    • Laceration: Shield eye (NO patch), urgent surgical repair.

Positive Seidel's test

⭐ A peaked pupil often points towards the site of a corneal perforation.

Chemical Corneal Burns - The Alkali-Acid Agony

  • Alkali Burns (More Severe):
    • Agents: Lime ($Ca(OH)_2$), $NaOH$, $NH_3$.
    • Mechanism: Saponification, ↑penetration. Liquefactive necrosis.
    • Prognosis: Worse. 📌 ALKALI is AWFUL.
  • Acid Burns (Less Severe):
    • Agents: $H_2SO_4$, $HCl$.
    • Mechanism: Protein coagulation, ↓penetration. Coagulative necrosis.
    • Exception: Hydrofluoric acid ($HF$) - acts like alkali.
  • Clinical: Pain, ↓vision, corneal opacity, limbal ischemia (key prognostic factor).
  • Grading (Roper-Hall): I-IV based on corneal clarity & limbal ischemia.
    • Grade IV: Opaque cornea, >50% limbal ischemia.
  • Management:
    • Immediate: Copious irrigation (>30 mins with saline/water).
    • Medical: Ascorbate, citrate, doxycycline, steroids (cautiously).
    • Surgical: Amniotic Membrane Transplant (AMT), Limbal Stem Cell Transplant (LSCT).

Severe ammonia ocular burn with limbal ischemia

⭐ Alkali burns cause liquefactive necrosis, leading to deeper penetration and more severe, progressive damage compared to the coagulative necrosis of most acid burns which tends to be self-limiting.

Diagnosis, Management & Complications - Patching Up the Pane

  • Diagnosis:

    • History: Mechanism of injury (blunt, sharp, chemical, radiation).
    • Slit-lamp examination: Vital for assessing depth, extent, foreign bodies.
    • Fluorescein staining: Highlights epithelial defects (abrasions, ulcers).
    • Seidel’s test: Detects aqueous leak (globe perforation).
    • Imaging: B-scan (posterior segment), CT scan (intraocular foreign body, orbital fracture).
  • Management Principles:

    • Remove foreign bodies.
    • Topical antibiotics: Prophylaxis/treatment (e.g., Moxifloxacin).
    • Cycloplegics: (e.g., Homatropine, Cyclopentolate) for pain relief, prevent synechiae.
    • Pressure patching/Bandage contact lens: For large abrasions.
    • Tetanus prophylaxis.
    • Surgical repair: For full-thickness lacerations.
    • Chemical burns: Copious irrigation (📌 LITMUS test first! Saline/Ringer's lactate).

Positive Seidel test indicating corneal perforation

  • Complications:
    • Infection (corneal ulcer, endophthalmitis).
    • Corneal scarring, opacification.
    • Irregular astigmatism.
    • Traumatic cataract, glaucoma.
    • Sympathetic ophthalmia (rare).

Seidel’s test is crucial for identifying full-thickness corneal lacerations by observing fluorescein dye dilution from leaking aqueous humor under cobalt blue light.

High‑Yield Points - ⚡ Biggest Takeaways

  • Corneal abrasions: fluorescein stain positive; treat with topical antibiotics, cycloplegics.
  • Seidel's test (streaming fluorescein) confirms corneal perforation.
  • Penetrating injuries: rigid shield (no patch), systemic antibiotics, urgent referral.
  • Chemical burns: copious, prolonged irrigation crucial; alkali burns more severe.
  • Corneal foreign bodies: prompt removal, antibiotic cover; check for rust ring.
  • Hyphema (blood in AC) often indicates significant blunt trauma.
  • Suspect intraocular foreign body (IOFB) with high-velocity or penetrating trauma.

Practice Questions: Corneal Trauma

Test your understanding with these related questions

A patient presents with eye pain, redness, and blurred vision after sleeping in contact lenses. Fluorescein staining reveals a corneal ulcer. What is the most appropriate management?

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Flashcards: Corneal Trauma

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_____ keratopathy occurs due to exposure to UV rays.

TAP TO REVEAL ANSWER

_____ keratopathy occurs due to exposure to UV rays.

Labrador

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