INFECTION OF THE EYE

• Conjunctivitis


  Inflammation or infection involving the conjunctiva
• Keratitis


  Inflammation or infection involving the cornea
• Keratoconjunctivitis


  Inflammation or infection involving both the conjunctiva and the cornea
• Causes of eye infections

  • Bacteria
  • Viruses

  
• Bacterial conjunctivitis (pink eye)


  • Highly contagious
  • Transmitted through contact with eye/respiratory discharges, contaminated fingers, or fomites
  • Manifested by eye irritation, reddening of conjunctiva, swelling of eyelids, mucopurulent discharge, photophobia

  
• Haemophilus influenzae biogroup aegyptius

  Gram negative rod or coccobacillus associated with epidemics of acute, purulent conjunctivitis
• Streptococcus pneumoniae


  Gram positive diplococci, alpha hemolytic aerobically and beta hemolytic anaerobically, with virulence factors like adhesins, capsule, pneumolysin, and IgA protease
• Chlamydia trachomatis


  Resembles gram negative bacteria but lacks peptidoglycan in outer wall, has high lipid content, and is an obligate intracellular parasite
• Eye infections caused by Chlamydia trachomatis

  • Conjunctivitis
  • Inclusion conjunctivitis
  • Trachoma

  
• Trachoma


  Chronic keratoconjunctivitis caused by Chlamydia trachomatis serotypes A, B, Ba, and C, leading cause of preventable blindness in developing countries

  
• Neisseria gonorrhoeae


  Causes ophthalmia neonatorum, a neonatal infection acquired during passage through infected birth canal
• Crede's prophylaxis


  Instilling 1% silver nitrate, 1% tetracycline, or 0.5% erythromycin eye ointments immediately after delivery to prevent ophthalmia neonatorum
• Viral conjunctivitis


  Highly contagious, spreads through airborne means, self-limited, no purulent discharge
• Adenoviruses


  Double-stranded DNA viruses with fiber projections that function as attachment and hemagglutinin
• Adenovirus eye infections


  • Mild "swimming pool" conjunctivitis (serotypes 3 and 7)
  • Epidemic keratoconjunctivitis (serotypes 8, 19, and 23)

  
• Enterovirus 70 and Coxsackie A24 virus

  Cause acute hemorrhagic conjunctivitis, a highly contagious eye infection

  
• Herpes simplex virus type 1

  Causes severe keratoconjunctivitis with recurrences, second leading cause of blindness in the US
• Measles virus is associated with conjunctivitis and photophobia