Corneal Perforation

Corneal perforation is a full thickness defect of the cornea with leakage of aqueous humour and risk of iris prolapse, endophthalmitis and loss of the eye.

• Causes:
  • Infectious keratitis (bacterial, fungal, herpetic, acanthamoeba), the commonest.
  • Autoimmune melting: rheumatoid arthritis, granulomatosis with polyangiitis, peripheral ulcerative keratitis, Mooren ulcer, Sjogren syndrome.
  • Neurotrophic and exposure ulcers, severe dry eye.
  • Chemical burns, trauma, surgery (post-keratoplasty, pterygium with mitomycin), Terrien degeneration, descemetocele.
  • Corneal thinning in keratoconus (hydrops) and keratomalacia from vitamin A deficiency.
• Small perforations may seal with iris plugging, with a flat anterior chamber, and may cause synechiae.

• Sudden pain relief, then watering, reduced vision, flat or shallow anterior chamber, low intraocular pressure.
• Positive Seidel test: fluorescein dye is washed away by flowing aqueous.
• Iris prolapse (dark, brownish tissue) or fibrin plug at the perforation, distorted pupil.
• Descemetocele: bulging Descemet membrane at the base of an ulcer, with imminent perforation.
• Features of infection: hypopyon, dense infiltrate, purulent discharge.

• Slit lamp (without pressing on the globe), fluorescein with Seidel test; anterior segment OCT to measure residual thickness.
• Cultures and scrapings from the ulcer margin for bacteria, fungi and acanthamoeba before any therapy; avoid contact in the case of descemetocele.
• Investigate the cause: autoimmune screen (rheumatoid factor, ANCA, ANA), diabetes, vitamin A level, infectious markers.
• B-scan ultrasound if the view is poor.

• Protect the eye with a shield, no pressure, no further manipulation; avoid Valsalva and straining; stop topical steroids and preservative containing agents if infection is suspected.
• Reduce aqueous flow: acetazolamide 250 mg orally four times daily (or 500 mg slow release twice daily), timolol 0.5 percent twice daily, to allow closure; oral doxycycline 100 mg twice daily and vitamin C 1 g daily to inhibit melting.
• Antimicrobial cover: fortified cefuroxime 5 percent and gentamicin 1.5 percent (or tobramycin 1.5 percent) hourly, or moxifloxacin 0.5 percent hourly; add antifungal (natamycin 5 percent hourly) if fungal. Oral moxifloxacin 400 mg daily or ciprofloxacin 750 mg twice daily for deep infections.
• Management by size:
  • Microperforation (under 1 mm, formed chamber): bandage contact lens, aqueous suppressants, antibiotic cover, close observation.
  • Small (1 to 3 mm): cyanoacrylate tissue adhesive applied after drying the bed and removing necrotic epithelium, covered by a bandage contact lens; glue is replaced as needed every 1 to 2 weeks.
  • Larger (3 to 5 mm) or unstable: multilayered amniotic membrane graft, corneal patch graft, or sutured tectonic lamellar keratoplasty.
  • Greater than 5 mm or with extensive melt: penetrating tectonic keratoplasty with a large diameter graft, which may need a conjunctival flap if graft not available.
• Reconstruct the anterior chamber with viscoelastic or air at surgery; preserve iris tissue (abscise only necrotic prolapse).
• Treat the underlying cause (immunosuppression for autoimmune melt, tarsorrhaphy for neurotrophic and exposure disease).
• Follow daily initially for leakage, anterior chamber depth, pressure, infection; look for endophthalmitis (hypopyon, vitritis).
• Later optical rehabilitation: keratoplasty after the eye is quiet.