Management of Severe Anterior Chamber Reaction Suggestive of Infectious Keratitis After LASIK

Diagnostic Evaluation

A grade +4 anterior chamber reaction occurring 12 years after LASIK strongly indicates infectious keratitis rather than typical postoperative inflammation, prompting urgent work‑up. [1][2]
LASIK‑associated microbial keratitis characteristically presents with pain, redness, photophobia, focal corneal infiltrates that extend beyond the lamellar interface, and a marked anterior chamber reaction. [1][2]
Infection may arise early or late in the postoperative period; the timing and severity depend on the causative organism. [1][2]
The microbiologic spectrum of LASIK‑related infections differs from other corneal infections and includes atypical mycobacteria, methicillin‑resistant Staphylococcus aureus, Nocardia spp., fungi, and herpes simplex virus. [1][2]

Obtain corneal scrapings from the affected area and send them for bacterial, fungal, and viral cultures (including atypical mycobacteria and Nocardia). [1][2]
When the flap interface is involved but no surface ulceration is visible, elevate the LASIK flap to allow direct access for scrapings. [1][2]

Initiate intensive broad‑spectrum topical antibiotics immediately after cultures are taken. [1][2]
If the infiltrate involves the flap interface and flap elevation is performed, apply the antibiotic directly onto the interface. [1][2]
Adjust the antimicrobial regimen according to culture results and the clinical response. [1][2]

Measure intra‑ocular pressure peripherally to the flap edge (not centrally) to assess for pressure‑induced stromal keratitis, as interface fluid can give falsely low central readings. 3

Lack of response to corticosteroids should raise suspicion for microbial keratitis. 3
Topical corticosteroids can worsen infection and mask its progression. 3
Prior use of intensive topical steroids may modify the clinical presentation and increase the severity of an underlying infection. [1][2]

Severe infection involving the flap or deep stromal layers may necessitate flap amputation to achieve infection control. [1][2]
When medical therapy fails to halt disease progression, surgical debridement should be considered. [1][2]
Epithelial ingrowth is a recognized risk factor for the development of microbial keratitis after LASIK. [1][2]

Infectious keratitis after LASIK follows a progressive course with worsening pain, redness, and photophobia, requiring aggressive antimicrobial treatment. [1][2]
Clinical improvement should be evident within 48–72 hours of therapy; absence of response mandates review of culture data and modification of the treatment plan. [1][2]

Post‑LASIK microbial keratitis often presents with focal infiltrates that extend beyond the lamellar interface into deeper or superficial stroma while the epithelium remains intact, so a negative fluorescein stain does not exclude infection. 4
Prior intensive topical corticosteroid therapy can mask the severity of infection and alter the clinical appearance, making diagnosis more challenging. 4

When the infection involves the flap interface but no surface ulceration is visible, the LASIK flap must be elevated to obtain scrapings directly from the interface and stromal bed. 4
Delaying flap elevation in suspected interface involvement compromises access to infected tissue and should be avoided. 4

Specimens should be taken from both the undersurface of the lifted flap and the residual stromal bed using a sterile blade, platinum spatula, or jeweler’s forceps. 5
Scraping must include material from the base and the peripheral margin of the infiltrate; collecting only purulent material yields inadequate microbiologic results. 5

The microbial spectrum of LASIK‑associated infections differs from typical corneal infections and includes atypical mycobacteria, methicillin‑resistant Staphylococcus aureus, Nocardia species, filamentous fungi (e.g., Aspergillus, Acremonium, Fusarium), and herpes simplex virus. 4

Initiate intensive broad‑spectrum topical antibiotics immediately after specimens are obtained. 4
If the infiltrate involves the flap interface, apply the antibiotic directly onto the interface to ensure drug delivery to the infected plane. 4

Do not assume that a negative fluorescein stain rules out infection; interface infections frequently lack epithelial defects. 4
Do not rely solely on clinical appearance to differentiate bacterial from fungal keratitis—culture‑based identification is necessary because specialists correctly identify the pathogen in fewer than 70 % of cases without laboratory confirmation. 4