Practical approach

1. Immediate priorities: protect the eye and assess integrity

• Admit or arrange same-day cornea specialist / therapeutic keratoplasty capability.
• Place a rigid eye shield, not a pressure patch.
• Do not press on the globe, attempt to peel the iris from the cornea at the slit lamp, or perform tonometry if the wound is openly leaking/unstable.
• Record visual acuity if possible, relative afferent pupillary defect, and examine the fellow eye.
• Slit-lamp assessment:
  • ulcer size, location, depth and infiltrate edge
  • active leak or Seidel positivity, if safe to test
  • extent and viability of iris incarceration
  • anterior chamber depth, hypopyon/fibrin, lens involvement
  • posterior segment with B-scan only if view is absent and globe integrity is sufficiently secure.

1. an active melting infectious ulcer with ongoing perforation, or
2. a chronic sealed perforation with pseudocornea/adherent leucoma, but with residual infection or structural consequences.

2. Establish the cause before treatment, without delaying treatment

• Gram stain and bacterial culture/sensitivity
• KOH/calcofluor and fungal culture
• Additional testing for Acanthamoeba, atypical mycobacteria, HSV, or biopsy when suggested by history or appearance.

• Contact lens use, rapidly progressive suppuration: consider Pseudomonas.
• Vegetative trauma, feathery infiltrate, satellite lesions: suspect filamentous fungus.
• Severe pain out of proportion, water exposure/contact lenses, ring infiltrate: consider Acanthamoeba.
• Peripheral melt with minimal discharge: investigate autoimmune peripheral ulcerative keratitis.

3. Treat as active infectious keratitis

• Start intensive topical broad-spectrum antimicrobial therapy immediately after cultures, or immediately if cultures would delay therapy.
• Use fortified, culture-directed treatment for severe/central/large ulcers according to local corneal-service protocol.
• Add cycloplegia for pain and to limit posterior synechiae.
• Control elevated IOP if present with appropriate aqueous suppressants.
• Use systemic antimicrobial therapy when there is scleral extension, gonococcal infection, risk of intraocular spread, or a specific organism/clinical indication.
• Avoid topical corticosteroids while there is uncontrolled infection, progressive melt, fungal disease concern, or an unsealed perforation. They are considered only later by the treating cornea specialist once infection is controlled and the structural situation is secure.

4. Restore tectonic integrity: choose the procedure by defect size, location, and iris prolapse

A. Tiny, contained perforation with controlled infection

• Cyanoacrylate tissue adhesive, often with a bandage contact lens, can temporize or seal the perforation.
• Continue intensive antimicrobials after gluing.

B. Iris incarceration with pseudocornea

1. Remove necrotic/infected cornea and obtain tissue for microscopy/culture.
2. Re-form the anterior chamber with viscoelastic.
3. Carefully assess the incarcerated iris:
   • preserve and reposition viable iris if feasible;
   • excise only clearly nonviable, infected, or irreducibly damaged prolapsed iris;
   • release anterior synechiae as safely as possible.
4. Perform peripheral iridectomy where indicated to reduce pupillary block risk.
5. Address lens involvement only if necessary for infection control or anatomy.
6. Restore the globe with a tectonic patch graft, lamellar patch graft, or therapeutic/tectonic penetrating keratoplasty.

C. Indications favoring urgent therapeutic/tectonic penetrating keratoplasty

• Perforation larger than about 2-3 mm
• Flat or poorly formed anterior chamber
• Significant iris prolapse/incarceration
• Progressive stromal melt despite maximal antimicrobial treatment
• Deep/large infiltrate, especially central
• Infection extending toward limbus/sclera or concern for intraocular extension
• Failed glue, failed amniotic membrane/patch approach, or unsuitable tissue bed.

5. Postoperative priorities

• Continue organism-directed topical antimicrobials.
• Monitor very closely for recurrent infiltrate, graft infection, wound leak, shallow chamber, hypopyon, secondary glaucoma, cataract, and endophthalmitis.
• Introduce topical steroid only when the surgeon judges infection inactive and the graft/wound stable.
• Treat surface disease and the underlying cause: contact-lens hygiene, lid disease, neurotrophic cornea, exposure, dry eye, autoimmune disease, or immunosuppression where relevant.

Key examination-style summary