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Basics ⬇

Basics

Definition

  • Penetrating-a wound or foreign body enters but does not completely pass through the cornea or sclera.
  • Perforating-a wound or foreign body completely passes through the cornea or sclera; greater risk of vision loss than penetrating.
  • Simple-involves only the cornea or sclera; may be penetrating or perforating; other ocular structures intact.
  • Complicated-perforating; involves other structures besides the cornea or sclera; uveal, vitreal, or retinal incarceration or prolapse through the wound; traumatic cataract; hyphema; lid lacerations.

Pathophysiology

  • Sharp trauma-wounds by an outside-in mechanism.
  • Blunt trauma-wounds by an inside-out mechanism; eye undergoes sudden changes in its equatorial and axial dimensions and IOP; actual wound may be at a site other than the point of impact; often more damaging than sharp trauma.
  • All or a portion of the foreign object initiating the injury may be retained in the wound or eye.

Systems Affected

  • Musculoskeletal-surrounding skull or orbital tissue
  • Nervous-unconsciousness or brain injury
  • Ophthalmic

Incidence/Prevalence

Common

Signalment

Species

Dog and cat

Signs

Historical Findings

  • Usually acute onset.
  • Often a history of running through heavy vegetation, being hit by gunshot pellets or other projectiles, or being scratched by a cat.
  • Trauma may not be observed.

Physical Examination Findings

  • Varies with tissues affected.
  • Common-corneal, scleral, or eyelid deformity; edema; hemorrhage.
  • May see a retained foreign body.
  • Often rapidly seals; may appear only as a subconjunctival hematoma.
  • May also see iris defects, pupil distortion, hyphema, cataract, vitreal hemorrhage, retinal detachment, and exophthalmia.

Causes

Blunt or sharp trauma

Risk Factors

  • Preexisting visual impairment
  • Young, naive, or highly excitable animals
  • Hunting or running through heavy vegetation
  • Fighting

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • History or a retained foreign body usually diagnostic.
  • Traumatic event not observed and no foreign body found-consider non-traumatic causes of corneal ulceration, hyphema, etc.
  • Traumatic hyphema-almost invariably accompanied by corneal or scleral lesions and subconjunctival or periocular hemorrhage.
  • Traumatic cataracts-disrupted lens capsule common.
  • Traumatic retinal detachment-almost invariably accompanied by intraocular hemorrhage.

CBC/Biochemistry/Urinalysis

  • Usually noncontributory.
  • Consider as a preanesthesia screen or when non-traumatic cause is possible.

Other Laboratory Tests

  • Cytologic examination and aerobic culture and sensitivity testing of the wound and foreign body-recommended even if infection is not apparent; may need to collect specimen under general anesthesia at the time of surgery.
  • Consider other tests (platelet count, coagulation profile, etc.) if non-traumatic causes are possible.

Imaging

  • Ocular ultrasonography-if the ocular media are opaque; may clarify the extent and nature of intraocular disease; may detect foreign body.
  • Orbital radiographs, CT or MRI (if non-metallic)-may help determine projectile's course; may detect foreign body.

Diagnostic Procedures

  • Determine the nature, force, and direction of impact of the object-help identify which tissues may be involved.
  • Do not put pressure on the eye until rupture or laceration of the globe has been ruled out.
  • Assess vision-menace response; aversion to bright light.
  • Periocular skin and orbit-examine for lacerations or deformities; suspect globe involvement if a lid laceration crosses the eyelid margin or penetrates the orbital septum; entry sites are often small and quickly seal.
  • Abnormal ocular motility-suggests extraocular muscle trauma, orbital hemorrhage or edema, retained foreign bodies or peripheral nerve or CNS damage.
  • Scleral rupture-consider this possibility with subconjunctival hemorrhage, especially if the anterior chamber is abnormally deep or shallow, there is vitreal hemorrhage, or the eye is abnormally soft.
  • Pupils-size; shape; symmetry; direct and consensual light reflexes.
  • Detailed ophthalmoscopy-assess clarity of ocular media and fundus integrity; rule out intraocular foreign body.
  • Seidel test-if any question of corneal or scleral leaking; use a dry to slightly moist fluorescein strip to paint a thin coat of fluorescein over the surface of the defect; leaking aqueous combines with the orange fluorescein, forming a bright green rivulet (seen best with cobalt illumination).

Pathologic Findings

  • Depends on wound and affected tissues.
  • Usually correlates closely with clinical examination findings.
  • Vitreal hemorrhage-may organize into a fibrous band that applies traction to the retina, causing it to detach.
  • Post-traumatic sarcoma (cats)-may occur months to years after severe ocular trauma.

Treatment ⬆ ⬇

Treatment

Appropriate Health Care

  • Depends on severity.
  • Outpatient-if integrity of the globe is ensured.

Nursing Care

  • Sedation-consider for excited or fractious patients.
  • When walking-apply an Elizabethan collar and use a harness or put ipsilateral foreleg through the leash to avoid increasing intraocular pressure in affected eye.
  • Avoid third eyelid flaps in patients with perforations or deep/long penetrating wounds until the wound is stable.

Injuries Considered for Medical Treatment

  • Non-perforating wounds with no wound edge override or gape-apply an Elizabethan collar; give topical antibiotic or atropine ophthalmic solutions.
  • Non-perforating wounds with mild wound gape or shelved edges-apply a therapeutic soft contact lens and an Elizabethan collar; give topical antibiotic or atropine ophthalmic solutions.
  • Simple full-thickness, pinpoint corneal perforation with a negative Seidel test that has a formed anterior chamber and no uveal prolapse-sedentary patients; use a therapeutic soft contact lens and an Elizabethan collar; give topical antibiotic or atropine ophthalmic solutions; reexamine a few hours after applying the lens and at 24 and 48 hours.

Activity

Usually confined indoors (cats) or limited to leash walks until healing is complete. A harness is preferred to a collar to reduce pressure on the neck and the risk of increased intraocular pressure and wound leaks.

Client Education

Warn client that the full extent of the injury (cataracts, retinal detachment, infection) may not be apparent until several days or weeks after the injury and that long-term follow-up is necessary.

Surgical Considerations

Injuries Requiring Surgical Exploration or Repair

  • Full-thickness corneal lacerations with a positive Seidel test.
  • Full-thickness wounds with iris incarceration or prolapse.
  • Full-thickness scleral or corneoscleral lacerations.
  • Suspected retained foreign body or a posterior scleral rupture.
  • Simple non-perforating wound with edges that are moderately or overtly gaping and that are long or more than two-thirds the corneal thickness.

Injuries Considered for Surgical Exploration or Repair

  • Small full-thickness corneal lacerations with a negative Seidel test and no uveal incarceration or prolapse.
  • Large conjunctival lacerations.
  • Partial-thickness corneal or scleral lacerations in an active patient.

Medications ⬆ ⬇

Medications

Drug(s) Of Choice

Antibiotics

  • Complicated wounds, those with retained plant material, and those caused by blunt trauma with tissue devitalization-infection common.
  • Bacterial endophthalmitis-5–7% of perforations; very rare in wounds that only penetrate but do not perforate the cornea.
  • Penetrating-topical antibiotics alone (e.g., neomycin, polymyxin B, and bacitracin) or gentamicin solution q6–8h; usually sufficient.
  • Perforating wounds with negative Seidel test-systemic ciprofloxacin (dogs, 10–20 mg/kg PO q24h); topical cefazolin (33 mg/mL by adding injectable cefazolin to artificial tears) and fortified gentamicin or tobramycin (add injectable aminoglycoside to the commercial ophthalmic solution to achieve a final concentration of 14 mg/mL), both drugs q4–6h.
  • Perforating wounds with positive Seidel test-systemic ciprofloxacin (dogs, 10–20 mg/kg PO q24h); topical cefazolin and fortified gentamicin or tobramycin as noted above, only after defect has been made watertight.

Anti-Inflammatories

  • Topical 1% prednisolone acetate or 0.1% dexamethasone solution q6–12h; as soon as the wound is sutured or has epithelialized (becomes fluorescein stain negative), as long as infection is not present.
  • Systemic prednisone 0.5–1 mg/kg q12h–q24h; for sutured or epithelialized wounds when inflammation is severe; when the lens or more posterior structures are involved; when the wound is infected or not epithelialized and control of inflammation is mandatory to preserve the eye.
  • Topical NSAIDs-flurbiprofen or one of several others; may be used if topical corticosteroids are contraindicated and control of inflammation is mandatory to preserve the eye.

Mydriatics

  • 1% atropine ophthalmic solution q6–12h; when there is significant miosis or anterior chamber reaction.

Analgesics

  • Topical atropine or oral aspirin (dogs, 10–15 mg/kg PO q12h to q8h)-may provide sufficient pain relief.
  • Carprofen 2.2 mg/kg PO q12h or 4.4 mg/kg PO once daily.
  • Tramadol-start at 1–2 mg/kg q12h and can increase up to 5 mg/kg q6h or as needed.
  • Butorphanol: dogs, 0.2–0.4 mg/kg; cats, 0.1–0.2 mg/kg IV, SC, or IM q2–4h or as needed; acute mild pain; sedation not required.
  • Oxymorphone: dogs, 0.05–0.1 mg/kg; cats, 0.05 mg/kg IV, SC, or IM q4–6h or as needed; acute severe pain; sedation required.
  • Naloxone 0.04 mg/kg IV, SC, or IM; to reverse narcotics.

Contraindications

  • Topical ophthalmic ointments-avoid in perforations with positive Seidel test until wound closed.
  • Systemic ciprofloxacin-avoid in small and medium dog breeds aged 2–8 months; avoid in large dog breeds aged 2–12 months; avoid in giant dog breeds aged 2–18 months; potential for damaging rapidly growing articular cartilage.

Precautions

  • Aminoglycosides-topical application may be irritating and may impede reepithelization if used frequently or at high concentrations; possibility of toxicity when given to very small patients or when giving by more than one route.
  • Topical solutions may be preferable to ointments if corneal integrity is questionable.
  • Atropine-may exacerbate KCS and glaucoma.
  • Topical or systemic NSAIDs-use cautiously with hyphema; safety of topical NSAIDs in cats unknown.

Possible Interactions

Systemic NSAIDs-may potentiate the nephrotoxicity of aminoglycosides; ensure good hydration and adequate renal function, especially in small dogs.

Alternative Drug(s)

Topical ciprofloxacin ophthalmic solution-may be used instead of the combination of topical cefazolin and a fortified aminoglycoside; some streptococcus are resistant.

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

  • Deep or long penetrating wounds that have not been sutured and perforating wounds-recheck q24–48h for the first several days to ensure integrity of the globe, to monitor for infection, and to check control of ocular inflammation.
  • Superficial penetrating wounds-usually recheck at 3- to 5-day intervals until healed.
  • Antibiotic therapy-alter according to culture and sensitivity results.

Prevention/Avoidance

  • Take care when introducing new puppies to households with cats that have front claws.
  • Minimize running through dense vegetation or the owner should consider having a bottle of saline eyewash to irrigate foreign debris from the eye.
  • Minimize visually impaired or blind dog's exposure to dense vegetation.

Possible Complications

  • Loss of the eye or vision.
  • Chronic ocular inflammation or pain.
  • Post-traumatic sarcoma-may develop in blind cat eyes that have been severely traumatized.

Expected Course and Prognosis

  • Most eyes with corneal lacerations or a retained corneal foreign body are salvageable.
  • The more posterior the injury, the poorer the prognosis for retention of vision.
  • Poor prognosis-scleral or uveal involvement; no light perception; perforating injuries involving the lens or with significant vitreal hemorrhage or retinal detachment.
  • Penetrating injuries usually better prognosis than perforating injuries.
  • Blunt trauma carries a poorer prognosis than sharp trauma.

Miscellaneous ⬆

Miscellaneous

Associated Conditions

Depends on nature and extent of injury.

Pregnancy /Fertility/Breeding

  • Systemic corticosteroids-may complicate pregnancy.
  • Systemic ciprofloxacin-probably should be avoided during pregnancy.

Abbreviations

  • CNS = central nervous system
  • CT = computed tomography
  • IOP = intraocular pressure
  • KCS = keratoconjunctivitis sicca
  • NSAID = nonsteroidal anti-inflammatory drug

Suggested Reading

Ledbetter EC, Gilger BC. Diseases and surgery of the canine cornea and sclera. In: Gelatt KN, Gilger BC, Kern TJ, eds., Veterinary Ophthalmology, 5th ed. Ames, IA: Wiley Blackwell, 2013, pp. 976–1049.

Author Paul E. Miller

Consulting Editor Paul E. Miller

Client Education Handout Available Online