cornea disorder

• Punctate epithelial erosions (PEE)


  Generally an early sign of epithelial compromise
• Punctate epithelial keratitis (PEK)

  Granular, opalescent, swollen epithelial cells, with focal intraepithelial infiltrates
• Subepithelial infiltrates


  Tiny subsurface foci of non-staining inflammatory infiltrates
• Superficial punctate keratitis


  A non-specific term describing any corneal epithelial disturbance
• Filaments


  Strands of mucus admixed with
• Epithelial edema


  Subtle cases may manifest with loss of normal corneal luster
• Superficial neovascularization


  A feature of chronic ocular surface irritation or hypoxia
• Pannus


  Superficial neovascularization accompanied by degenerative subepithelial change extending centrally from the limbus
• Infiltrates


  Focal areas of acute stromal inflammation composed of inflammatory cells, and cellular and extracellular debris including necrosis
• Ulceration


  Tissue excavation associated with an epithelial defect
• Vascularization


  Ghost vessels
• Lipid deposition


  May follow chronic inflammation with leakage from corneal new vessels
• Descemetocele


  A bubble-like herniation of Descemet membrane into the cornea
• Breaks in Descemet membrane

  May be due to corneal enlargement (Haab striae in infantile glaucoma) or deformation
• Seidel test


  Demonstrates aqueous leakage
• Signs to look for when documenting corneal examination

  • Opacities
  • Epithelial edema
  • Hypopyon
  • Blood vessels
  • Pigmented lesions
• Principles of Treatment


  • Control of infection & inflammation
  • Promotion of Epithelial healing
• Control of infection & inflammation

  • Antimicrobial agents
  • Topical steroids
  • Systemic immunosuppressive agents
• Promotion of Epithelial healing

  • Reduction of exposure
  • Lubrication
  • Bandage SCL
  • Surgical eyelid closure
  • Smoking
• Bacterial keratitis


  Usually only develops when the ocular defences have been compromised
• Bacteria that can penetrate a normal corneal epithelium

  • N. gonorrhoeae
  • N. meningitidis
  • C. diphtheriae
  • H. influenzae
• Common bacteria causing bacterial keratitis

  • Pseudomonas aeruginosa (60% CL related)
  • Staphylococcus aureus (skin & Conjunctivitis)
  • Streptococci. S. pyogenes (throat, gental) most aggressive
• Risk factors for bacterial keratitis

  • CL wear
  • Trauma
  • Ocular surface disease
  • Vit A, diabetes, immunocompromised
• Presentation of bacterial keratitis

  Pain, photophobia, blurred vision and mucopurulent or purulent discharge
• Signs of bacterial keratitis

  • Epithelial defect
  • Enlargement of the infiltrate
  • Stromal edema
  • Chemosis and eyelid swelling
  • Severe ulceration
  • Scarring, vascularization and opacification
• Fungal keratitis is rare in temperate countries but is a major cause of visual loss in tropical and developing countries
• Types of fungi causing keratitis

  • Yeasts (responsible for most cases in temperate climates)
  • Filamentous fungi (most common pathogens in tropical climates)
• Predisposing factors for fungal keratitis

  • Long-term use of steroids
  • CL wear
  • Systemic immunosuppression
  • Diabetes
• Candida keratitis


  Yellow-white densely suppurative infiltrate
• Filamentous keratitis


  A grey or yellow-white stromal infiltrate with indistinct fluffy margins
• Microsporidia


  A phylum of obligate intracellular one-celled parasites previously thought to be protozoa but recently reclassified as fungi
• Microsporidial keratitis


  • Bilateral chronic diffuse punctate epithelial keratitis
  • Unilateral slowly progressive deep stromal keratitis may rarely affect immunocompetent patients
• Herpes simplex virus (HSV)


  HSV is enveloped with a cuboidal capsid and has a linear double-stranded DNA genome. The two subtypes are HSV-1 and HSV-2
• Primary infection


  Without previous viral exposure, usually occurs in childhood and is spread by droplet transmission, or less frequently by direct inoculation
• Recurrent infection


  Reactivation in the presence of cellular and humoral immunity
• After primary infection


  1. Virus is carried to the sensory ganglion where latent infection is established

  2. Virus is incorporated in HOST DNA & cannot be eradicated

  3. Subclinical reactivation can occur periodically

  4. Clinical reactivation occurs due to various stressors
• Pattern of disease


  Remote from the site of reactivation, multiple reactivation may occur in a lifetime
• Rate of Ocular recurrence

  10% @ 1 yr, 50% at 10 yrs
• Risk factors for severe HSV cases

  • Atopic eye disease
  • Childhood
  • Immunodeficiency or suppression
  • Malnutrition
  • Measles and malaria
• Epithelial keratitis


  Dendritic or geographic keratitis associated with ACTIVE VIRUS replication