Penetrating and Perforating Injuries

Definitions & Classification - Eye Spy Injury Types

BETT Classification (Birmingham Eye Trauma Terminology System):

• Closed Globe Injury: Eyewall (cornea & sclera) NOT breached.
  • Contusion: No full-thickness wound (e.g., corneal abrasion).
  • Lamellar Laceration: Partial-thickness wound.
• Open Globe Injury: Full-thickness eyewall defect.
  • Rupture: Blunt trauma; eyewall breach at weakest point (limbus, old incision, post. to muscle insertion).
  • Laceration: Sharp object.
    • Penetrating Injury: Single entry wound. No exit. May have IOFB. 📌 Penetrating = Entry only.
    • Perforating Injury: Two wounds (entry AND exit). 📌 Perforating = Entry & Exit.
    • Intraocular Foreign Body (IOFB): Retained foreign object in globe.

⭐ Globe rupture from blunt trauma most commonly occurs superonasally, posterior to the rectus muscle insertions.

Clinical Evaluation - Spotting the Damage

• History:

  • Mechanism (sharp object, projectile), symptoms (pain, ↓vision, foreign body sensation).

• Ocular Examination:

  • Visual Acuity (VA): Often severely ↓.
  • Intraocular Pressure (IOP): Typically ↓ (aqueous leak); can be normal/↑.
  • Pupil: Peaked (points towards wound), irregular, Relative Afferent Pupillary Defect (RAPD) may be present.
  • Cornea/Sclera:
    • Full-thickness laceration, uveal/vitreous prolapse.
    • Seidel's test: Positive (aqueous humor leakage visualized with fluorescein dye under cobalt blue light).
  • Anterior Chamber (AC): Shallow/flat, cells, flare, hyphema.
  • Lens: Traumatic cataract, subluxation/dislocation.

• Investigations:

  • B-scan Ultrasonography: Useful if posterior view is obscured by media opacity (e.g., hyphema, cataract).
  • CT scan (orbit): Non-contrast, thin axial/coronal cuts for Intraocular Foreign Body (IOFB) localization (NO MRI if metallic IOFB suspected).

⭐ A shallow anterior chamber combined with low IOP is highly suggestive of globe perforation until proven otherwise.

Management Strategy - Patch & Dispatch

• Goal: Stabilize, prevent further damage/infection, arrange urgent surgical repair.
• **Immediate Actions (Pre-referral):
  • DO NOT remove impaled foreign body.
  • DO NOT apply pressure patch (risk of extrusion).
  • Protect eye: Rigid shield (e.g., Fox shield).
  • Nil Per Oral (NPO) - for surgery.
  • Antiemetics: IV Ondansetron (4-8 mg) to prevent Valsalva → ↑IOP.
  • Analgesia: Paracetamol (avoid NSAIDs).
  • Tetanus prophylaxis: (TT 0.5 mL IM if needed).
  • Systemic IV Antibiotics (prevents endophthalmitis):
    • Ceftazidime 1g IV q12h + Vancomycin 1g IV q12h.
    • (Alt: Moxifloxacin 400mg IV/PO OD).
  • Urgent ophthalmologist referral (“Dispatch”) for surgical repair.

⭐ Primary repair of an open globe injury is ideally performed within 24 hours to minimize endophthalmitis risk and optimize visual outcome.

Complications & Prognosis - The Aftermath

• Key Complications:

  • Endophthalmitis: Severe intraocular infection.
    • Prompt intravitreal antibiotics vital.
  • Sympathetic Ophthalmia: Rare bilateral granulomatous panuveitis.
    • Affects uninjured (sympathizing) eye.
  • Retinal Detachment: Can cause profound vision loss.
  • Traumatic Cataract: Lens opacification.
  • Secondary Glaucoma: Elevated IOP (↑IOP).
  • Phthisis Bulbi: Shrunken, non-functional end-stage eye.

• Ocular Trauma Score (OTS): Predicts visual outcome.

  Factor	Points
  Initial Visual Acuity
  No Light Perception (NLP)	60
  Light Perception (LP)/Hand Motion (HM)	70
  1/200-19/200	80
  20/200-20/50	90
  ≥20/40	100
  Negative Factors (Deduct)
  Globe Rupture	-23
  Endophthalmitis	-17
  Perforating Injury	-14
  Retinal Detachment	-11
  Afferent Pupillary Defect (APD)	-10
  Sum points for final OTS (0-100); predicts visual prognosis.

⭐ Sympathetic ophthalmia can occur weeks to years after initial injury; highest risk within 3 months to 1 year.

High‑Yield Points - ⚡ Biggest Takeaways

• Penetrating injuries have an entry wound only; perforating injuries have entry and exit wounds.
• Positive Seidel's test (fluorescein streaming) indicates an aqueous humor leak.
• High risk of infectious endophthalmitis; requires prompt systemic and topical antibiotics.
• Surgical exploration and primary repair are definitive management.
• Sympathetic ophthalmia is a rare, bilateral granulomatous uveitis post-trauma.
• Always suspect and rule out intraocular foreign body (IOFB), often requiring CT scan for localization.
• Tetanus prophylaxis is essential in all open globe injuries.