What is the management for a patient with keratoconus at risk for or with iris prolapse, possibly post-keratoplasty?

Management of Iris Prolapse in Keratoconus

Iris prolapse in keratoconus is a surgical emergency requiring immediate corneal transplantation, with penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty (DALK) as definitive treatment options, where DALK is preferred when technically feasible due to lower risk of endothelial rejection and globe rupture. 1

Immediate Surgical Management

For active iris prolapse, proceed directly to keratoplasty without delay. The presence of iris prolapse indicates full-thickness corneal compromise that cannot be managed conservatively. 1

Choice of Keratoplasty Technique

• DALK is the preferred approach when the posterior cornea remains intact, offering no risk of endothelial rejection, lower risk of globe rupture compared to PK, and less progressive endothelial cell loss over time. 1

• PK remains an option when DALK is not technically feasible due to the extent of posterior corneal involvement or when surgical expertise is limited. 1

• Both techniques achieve excellent visual outcomes in keratoconus, with 98% of eyes reaching 6/12 (20/40) or better post-operatively in historical series. 2

Technical Considerations

• Use same-size trephines for host and donor corneas to maintain wound integrity and prevent post-operative complications including wound leak or recurrent iris prolapse. 2

• Expect post-operative refractive outcomes averaging -0.5D sphere with -3.8D cylinder, though individual variation is substantial. 2

• Approximately 6% of patients require subsequent keratorefractive surgery for residual astigmatism. 2

Prevention Strategy for At-Risk Patients

For patients with advanced keratoconus at risk for perforation and iris prolapse, implement aggressive preventive measures:

Disease Stabilization

• Perform corneal cross-linking (CXL) immediately in any patient with documented progressive keratoconus to halt disease progression before structural compromise occurs. 1, 3

• Document progression by comparing at least two topographic examinations 3-6 months apart, looking for steepening of anterior or posterior corneal surfaces, thinning, or increased rate of thickness change. 3

Behavioral Modification

• Mandate strict avoidance of eye rubbing, which directly accelerates keratoconus progression and increases risk of acute corneal decompensation. 1, 3

• For patients with allergic eye disease, prescribe cool compresses, preservative-free artificial tears, antihistamines, and mast cell stabilizers as first-line treatment. 3

• Use topical cyclosporine 0.05-0.1% for moderate-to-severe allergic conjunctivitis to reduce inflammation-driven rubbing behavior. 3

Visual Rehabilitation to Delay Surgery

• Trial specialty contact lenses (scleral or hybrid lenses) before considering keratoplasty, as these may delay or eliminate the need for transplantation even in advanced disease. 1, 3

• Rigid gas-permeable lenses remain the primary visual rehabilitation tool for moderate to advanced keratoconus. 3

Post-Keratoplasty Monitoring

Following transplantation for iris prolapse:

• Monitor for graft rejection, which manifests as donor corneal opacification in all cases to varying degrees. 4

• Watch for anterior synechiae formation, occurring in approximately 48.6% of cases. 4

• Assess for wound dehiscence and aqueous leakage, which are common post-operative complications requiring prompt intervention. 4

• Check intraocular pressure regularly if using topical corticosteroids, as steroid-induced IOP elevation can occur. 1

Critical Pitfalls to Avoid

• Do not attempt conservative management with contact lenses or medical therapy once iris prolapse has occurred—this is a surgical emergency. 1

• Do not delay referral to a corneal specialist for patients with progressive keratoconus showing signs of advanced thinning or scarring. 1

• Do not wait for additional vision loss before initiating CXL in patients with documented progression—early intervention preserves visual function. 1

• Patients with vernal or atopic keratoconjunctivitis require earlier surgical intervention and have higher risk for corneal hydrops (acute Descemet's membrane rupture), making aggressive disease management essential. 1