Cornea and External Diseases

Bacterial Corneal Ulcer

Bacterial keratitis demonstrating epithelial ulceration and conjunctival injection.
  • Sight-threatening infection.

Clinical Features

  • Present as an acute, rapidly progressive corneal destructive process or a chronic process.
  • Predisposing factors include: corneal epithelial disruption caused by trauma, contact lens wear, contaminated ocular medications and impaired immune defense mechanisms.
  • Symptoms: foreign body sensation, ocular pain, conjunctival injection, photophobia, tearing and decreased vision. 
  • Signs: initial ulceration may progress to stromal infiltrate, stromal abcess formation and necrosis or anterior segment inflammation.
  • May be complicated with intraocular infection.
  • Causative organisms include gram-positive cocci (Staphyloccocus sp. Streptococcus pneumoniae), aerobic gram-negative bacilli (Pseudomonas aerugenosa, Haemophilus influenzae, Moraxella catarrhalis.), enteric gram-negative bacilli or colonization of normal skin flora (Staphylococcus aureus, Streptococcus viridans)

Work Up

  • Corneal scrapings for stains and cultures. Consider additional studies to rule out fungal, Acanthamoeba or mycobacterial infections if suspected.
  • Antimicrobial susceptibility testing.
  • May culture the eyelid and conjunctiva, ophthalmic medication bottles or tubes, contact lenses, contact lens cases and solutions.

Management

  • Broad-spectrum topical antibiotic therapy.
  • Fortified subconjunctival or IV antibiotic are indicated if infection does not respond to initial treatment.
  • Cycloplegia.
  • Topical corticosteroids may be used to prevent scarring.
  • Therapeutic surgical penetrating keratoplasty is indicated when corneal perforation occurs.