Very late onset LASIK flap Acremonium fungal keratitis confirmed by metagenomic deep sequencing

Abstract

Purpose: To describe a unique case of LASIK flap fungal keratitis confirmed by next generation sequencing.

Observations: A 56-year-old female presented with refractory keratitis involving her LASIK flap 21 years after surgery. Confocal was positive for filamentous structures. The patient underwent immediate flap amputation followed by topical antifungal treatment. Corneal culture was positive for Acremonium sp. Metagenomic deep sequencing confirmed Acremonium as the primary source of infection and also identified Fusarium as a likely contributor of a mixed fungal infection. Sequencing also identified hay as the likely source of the infection. Treatment resulted in eradication of the infection. The patient's final best corrected visual acuity was 20/30 with rigid contact lens overrefraction.

Conclusions: Metagenomic deep sequencing is a novel diagnostic tool that is increasingly being utilized for diagnosis of refractory keratitis. This case demonstrates the diagnostic potential of deep sequencing for identifying post-LASIK keratitis and reinforces the utility of LASIK flap amputation in the setting of tectonic flap instability due to keratolysis.

Importance: This case highlights several important clinical points for treating LASIK flap keratitis and highlights the emerging role metagenomic sequencing has in the diagnosis of infectious keratitis. This is first known case using next generation sequencing to diagnose a post-LASIK infectious keratitis.

Keywords: LASIK Flap amputation; LASIK Fungal keratitis; Metagenomic deep sequencing.

Fig. 1

Slit lamp photograph showing dense infiltrate with loculated hypopyon (1A). Anterior segment optical coherence tomography revealing hyperreflectivity in the LASIK flap interface and along the endothelium (1B). Confocal microscopy (depth 55 μm) demonstrating numerous branching filamentous structures consistent with filamentous fungi (1C).

Fig. 2

External photo of flap lift with central buttonhole from infectious keratolysis (2A). Surgical pathology evaluation revealing fungal elements on the posterior edge of the amputated flap (2×B) (PAS stain, 20× magnification). Identification of Acremonium and Fusarium Sp. from the corneal flap and polymicrobial colonization of hay by metagenomic deep sequencing (MDS). Organisms are plotted as a function of matched read pairs per million read pairs (rM) at the species level based on nucleotide alignment (2C).