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Corneal Ulcer

URGENT — Cornea

Symptoms

Clinical presentation

  • Rapid-onset severe eye pain and redness.
  • Intense photophobia and foreign-body sensation.
  • Mucopurulent or purulent discharge (eyelids may stick together).
  • Blurred vision (severity depends on proximity to the visual axis).

Risk factors

  • Contact lens wear (overnight wear, poor hygiene) is the dominant modern risk.
  • Recent trauma, dry eye, or exposure keratopathy.
  • Chronic epithelial disease or prolonged topical steroid use.

Clinical Findings

Primary signs

  • Gray-white stromal infiltrate with an overlying epithelial defect (stains with fluorescein).
  • Conjunctival hyperemia and ciliary flush.
  • Anterior chamber (AC) cell and flare; hypopyon (layered pus) in severe cases.
  • Stromal edema and Descemet folds surrounding the infiltrate.

Etiology-specific clues

  • Fungal: feathery edges, satellite lesions, or endothelial plaques.
  • Acanthamoeba: ring infiltrate, perineuritis, and pain out of proportion to exam.
  • Bacterial (Gram-positive): thick mucopurulent discharge.

Complications & severity

  • Pseudomonas: characteristic "soupy" mucoid stromal melt; can perforate within 24–48 hours.
  • Descemetocele: extreme thinning where only Descemet membrane remains.
  • Perforation: full-thickness corneal breach.

Etiology

Bacterial

  • Pseudomonas aeruginosa (high-risk in contact lens wearers).
  • Staphylococcus aureus, Streptococcus, and Moraxella (associated with malnutrition/alcoholism).

Fungal

  • Fusarium (common after vegetative/plant trauma).
  • Aspergillus and Candida (common in chronic epithelial disease).

Acanthamoeba

  • Associated with contact lens wear and water exposure (pools, showers, hot tubs).

Non-infectious / sterile

  • Neurotrophic keratopathy (CN V lesions).
  • Autoimmune peripheral melt (Rheumatoid Arthritis, GPA).

Red Flags

Central ulcer >2 mm or vision <20/400 → urgent cornea specialist referral.

Rapidly progressing Pseudomonas melt → risk of perforation within 24–48 hours.

Descemetocele or clinical perforation → requires immediate surgical repair (glue or graft).

Misdiagnosing Acanthamoeba as HSV → steroids will accelerate tissue destruction.

Investigations

Slit-lamp assessment

  • Measure infiltrate size and epithelial defect dimensions exactly.
  • Assess corneal thinning and depth of involvement using a narrow beam.

Microbiology (scraping)

  • Mandatory for ulcers >2 mm, central/sight-threatening, or treatment-resistant.
  • Gram stain, Giemsa, KOH prep.
  • Cultures: blood, chocolate, and Sabouraud agars.
  • Culture contact lenses and lens cases if available.

Specialized imaging

  • Confocal microscopy for suspected Acanthamoeba or fungal infections.

Clinical Pearl

Pseudomonas in contact lens wearers is a "melt-down" emergency—it can perforate within 48 hours. Fungal ulcers typically feature feathery borders and satellite lesions. Never add steroids to the regimen until the infection is under control and the organism is known.

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