POST-LASIK CO-INFECTED KERATITIS (HSV, ACANTHAMOEBA, CANDIDA) WITH HYPOPYON: NEED FOR ADVANCED INTEGRATED DIAGNOSTICS

To describe the crucial usefulness of an integrated, multimodal diagnostic approach (optical and scanning electron microscopy cytology (Citosem®), in vivo confocal microscopy (IVCM), direct immunoassay on cytological sample, and culture) in the identification and management of a rare and severe corneal co-infection, in a patient who underwent LASIK.

A 38-year-old man presented with acute visual loss, severe pain, photophobia, and marked conjunctival hyperemia 4 days after LASIK surgery for myopia correction. Slit lamp examination revealed a central grayish corneal infiltrate with indistinct margins at the LASIK flap interface.

Given the recent surgical history, the presence of hypopyon, and the atypical herpetiform lesion, intensive diagnostic management was adopted:

1. Cytology and Corneal/Conjunctival Scraping: Rapid sampling for direct microscopic examination and for scanning microscopy (Citosem®).
2. In Vivo Confocal Microscopy (IVCM): Non-invasive, real-time visualization of microorganisms and corneal nerve structures.
3. Microbiological Culture: On specific media (for bacteria, fungi, Acanthamoeba).
4. Direct Immunofluorescence (IF) on Cytological Sample: For HSV type I and Chlamydia.

This integrated approach guided a targeted multi-drug treatment regimen. 

Diagnostic integration proved critical, revealing a complex picture not identifiable by culture alone:

• Optical Cytology and Citosem®: Cytology showed intense inflammation, neutrophilia, lymphocytosis, and spores. Scanning microscopy (Citosem®) revealed numerous Acanthamoeba cysts, Chlamydia, and Candida spores, in addition to cocci and Mycoplasma contamination.
• IVCM: Highlighted double-walled cysts and trophozoites compatible with Acanthamoeba along the nerve bundles (radial neuritis) and in the flap interface.
• Direct IF for HSV: Confirmed widespread Chlamydia and HSV-I infection.
• Initial Culture: Positive only for Streptococcus aureus growth, which did not fully account for the severe clinical presentation.

The final diagnosis was triple post-LASIK co-infection: Acanthamoeba keratitis, Candida keratitis, and HSV-I keratitis, with superinfection by Chlamydia and cocci, complicated by uveitis with hypopyon (exacerbated also by Mycoplasma).

Targeted treatment (systemic antivirals, topical amoebicides, and antifungals) led to the resolution of the hypopyon and a significant reduction in the infiltrate within eight weeks, with eradication of the infection after six months. 

This case illustrates the complexity and potential aggressiveness of post-LASIK infectious keratitis and underscores the fundamental importance of an advanced multi-factor diagnostic approach. Sole reliance on standard microbial culture could have led to a fatal delay in the diagnosis of Acanthamoeba and HSV-I. The combined use of IVCM and scanning microscopy cytology (Citosem®) is essential for the timely and targeted management of these rare and complex anterior segment diseases.