Corneal Ulcer

A corneal ulcer is a focal loss of corneal epithelium with underlying stromal tissue loss and inflammation. It is a descriptive diagnosis that spans infectious and sterile causes and has different urgencies by location and cause.

• Central ulcers (within 4 mm of the visual axis) carry greater visual risk; peripheral ulcers are often immune related and are associated with systemic disease.
• Infectious: bacterial, fungal, viral, and protozoal.
• Sterile or immune:
  • Marginal keratitis (staphylococcal hypersensitivity).
  • Peripheral ulcerative keratitis associated with rheumatoid arthritis, granulomatosis with polyangiitis, polyarteritis nodosa, systemic lupus, and inflammatory bowel disease.
  • Mooren ulcer: idiopathic, painful, progressive circumferential peripheral ulcer with an overhanging, undermined edge, no scleral involvement, and no systemic disease.
  • Vernal shield ulcer: oval superior epithelial defect in severe vernal keratoconjunctivitis with a plaque of mucus and fibrin.
  • Neurotrophic, exposure (lagophthalmos), and toxic ulcers.

• Pain, photophobia, tearing, redness, and visual blur; pain is reduced in neurotrophic ulcers.
• A crater with an epithelial defect staining with fluorescein, stromal infiltrate, and corneal thinning; descemetocele is a bulge of Descemet membrane at the base; perforation produces a shallow chamber with aqueous leak.
• Associated: anterior chamber reaction, hypopyon, and sectoral or diffuse injection.
• Pointers: crescent shaped ulcer parallel to the limbus with a clear zone (marginal keratitis); rapidly progressive circumferential melt with an overhanging edge (Mooren); adjacent scleritis and systemic vasculitic features (peripheral ulcerative keratitis).

• Slit lamp measurement of epithelial defect and infiltrate, thickness (OCT), and perforation (Seidel test).
• Scrapings for smear and culture in presumed infection, particularly large, central, hypopyon, or atypical ulcers.
• For peripheral ulcers: full blood count, ESR, CRP, rheumatoid factor, anti-CCP, ANA, ANCA, complement, urinalysis, chest radiograph, and hepatitis B and C and tuberculosis screening before immunosuppression.
• Exclude conjunctival involvement and neoplasia (conjunctival biopsy if atypical).

• Infectious ulcers follow antimicrobial protocols by organism; avoid steroids until the organism is controlled.
• Supportive therapy for all ulcers: preservative free lubricants (carboxymethylcellulose 0.5 percent hourly), cycloplegia (atropine 1 percent once daily), oral doxycycline 100 mg twice daily to inhibit collagenase, oral vitamin C 500 mg twice daily, and a bandage contact lens or lid closure when no infection.
• Marginal keratitis: treat blepharitis (lid hygiene, azithromycin 1.5 percent drops, oral doxycycline), plus a short course of topical steroid (fluorometholone 0.1 percent or prednisolone acetate 1 percent four times daily tapered over 1 to 2 weeks) with antibiotic cover.
• Peripheral ulcerative keratitis: urgent systemic immunosuppression, because it can precede life threatening vasculitis: prednisolone 1 mg/kg daily (or intravenous methylprednisolone 500 mg to 1 g daily for 3 days), plus cyclophosphamide 2 mg/kg daily or rituximab 375 mg/m2 weekly for 4 weeks or methotrexate 15 to 25 mg weekly; topical steroids alone are not enough.
• Mooren ulcer: topical steroid, topical ciclosporin 1 percent, conjunctival resection (with recession) at the involved sector, then systemic immunosuppression (ciclosporin, methotrexate, cyclophosphamide) for progressive or bilateral disease; keratoplasty.
• Vernal shield ulcer: topical steroid, mast cell stabiliser, topical tacrolimus 0.1 percent twice daily or ciclosporin 1 percent, and surgical debridement of the plaque with a bandage lens.
• Neurotrophic and exposure ulcers: eliminate toxic drops, lubricate, tape or tarsorrhaphy, botulinum toxin ptosis, amniotic membrane, autologous serum 20 to 50 percent drops, and cenegermin 20 micrograms/mL six times daily for 8 weeks.
• Descemetocele and small perforation (up to about 2 to 3 mm): cyanoacrylate glue applied to a dry, debrided base with a bandage lens; large perforations or extensive thinning: tectonic patch graft, lamellar or penetrating keratoplasty, and conjunctival flap.
• Follow up: daily to weekly, assessing healing and thickness. Prevent progression by early recognition and treatment of the underlying disease.
• Complications: scarring, perforation, secondary glaucoma, endophthalmitis, cataract, and permanent loss of vision.