What is the appropriate immediate management for a patient with a grade +4 anterior chamber reaction (cells/flare) and a history of laser‑assisted in situ keratomileusis (LASIK) performed 12 years ago?

Management of Grade +4 Anterior Chamber Reaction in Post-LASIK Patient

This patient requires immediate evaluation for microbial keratitis with corneal scrapings and initiation of intensive broad-spectrum topical antibiotics, as a +4 anterior chamber reaction 12 years after LASIK strongly suggests infectious keratitis rather than typical post-LASIK inflammation. 1

Critical Diagnostic Distinction

A grade +4 anterior chamber reaction occurring 12 years after LASIK is highly abnormal and demands urgent investigation:

• Normal post-LASIK inflammation peaks within 24 hours and resolves by day 7 with standard steroid therapy 2
• Microbial keratitis after LASIK characteristically presents with pain, redness, photophobia, focal corneal infiltrates extending beyond the lamellar interface, and anterior chamber reaction 1
• Infection can present either early or late in the postoperative period, with timing and severity varying by causative organism 1
• The microbiology of LASIK-associated infections differs from other corneal infections, including atypical mycobacteria, methicillin-resistant S. aureus, nocardia, fungi, and HSV 1

Immediate Management Algorithm

Step 1: Obtain Microbiological Diagnosis

• Perform corneal scrapings from the involved area and submit for microbiological investigation 1
• If the flap interface is involved but no surface ulceration is observed, elevate the flap to allow access for scrapings 1
• Culture for bacteria (including atypical mycobacteria and nocardia), fungi, and consider HSV testing 1

Step 2: Initiate Empiric Antimicrobial Therapy

• Start intensive broad-spectrum topical antibiotic therapy immediately after obtaining cultures 1
• If the infiltrate involves the interface and requires flap elevation, apply antibiotics directly to the flap interface 1
• Modify antibiotic regimen based on culture results and clinical response 1

Step 3: Assess for Alternative Diagnoses

While infection is most likely, evaluate for:

• Pressure-induced stromal keratitis: Check IOP peripheral to the flap edge (not centrally, as interface fluid causes artifactually low readings) 1
• Severe anterior uveitis: Though rare, fibrinous anterior uveitis can occur post-LASIK and requires systemic and intensive topical steroids with cycloplegics 3
• Diffuse lamellar keratitis (DLK): However, DLK typically presents with little or no discomfort despite visible inflammation, making it unlikely with significant AC reaction 4, 5

Critical Management Pitfalls

Avoid Prolonged Corticosteroid Use Without Diagnosis

• Inflammation unresponsive to corticosteroids should prompt consideration of microbial keratitis 1
• Corticosteroids can exacerbate infection and mask progression 1
• If intensive topical corticosteroids have been used, this may alter the clinical presentation and severity of infection 1

Recognize When Surgical Intervention Is Needed

• Severe infection of the flap or deep stroma may require flap amputation to control the infection 1
• If medical therapy fails to control infection, consider surgical debridement 1
• Epithelial ingrowth may be a risk factor for microbial keratitis development 1

Expected Clinical Course

• Normal post-LASIK inflammation: Mild to moderate discomfort only during the first postoperative day, with AC inflammation returning to baseline by day 7 5, 2
• Infectious keratitis: Progressive symptoms with pain, redness, and photophobia requiring aggressive antimicrobial therapy 1
• Treatment response: Monitor closely for clinical improvement within 48-72 hours; lack of response warrants culture review and treatment modification 1