Bacterial keratitis

I.        Describe the approach to establishing the diagnosis

A.     Describe the etiology of this disease

1.      Disruption of epithelial integrity, rarely occurs in eyes without trauma, preexisting corneal surface disorders or other predisposing condition

2.      Common etiological agents: Pseudomonas species, staphylococcal species, streptococcal species

B.     Define the relevant aspects of epidemiology of the disease

1.      Increased risk with contact lens wear, especially overnight wear

C.    List the pertinent elements of the history

1.      Ocular symptoms

a.      Erythema

b.      Ocular pain

c.      Loss of vision

d.      Discharge

e.      Light sensitivity

2.      Duration of symptoms

3.      Identification of risk factors

a.      Contact lens wear

b.      Preexisting ocular surface disease

c.      Corneal trauma

4.      Current ocular medications

D.    Describe pertinent clinical features

1.      Epithelial defect

2.      Stromal infiltrate

3.      Stromal ulceration

4.      Hypopyon

II.      List the most common or critical entities in the differential diagnosis

A.     Herpes simplex virus stromal keratitis

B.     Fungal keratitis

C.    Immune (non-infectious) keratitis

III.    Describe disease-related complications

A.     Corneal thinning and perforation

B.     Corneal opacification and neovascularization and irregular topography, with loss of vision

Additional Resources

1. AAO, Focal Points: Antibiotic Use in Corneal and External Eye Infections, Module #10, 1997, p.11-13.

2. AAO, Basic and Clinical Science Course. Section 11: Lens and Cataract, 2004-2005.

3. AAO, Preferred Practice Patterns Committee, Cornea and External Disease Panel. Bacterial Keratitis Preferred Practice Pattern, 2000.