Fungal Keratitis Post-FemtoLASIK: A Novel Therapeutic Approach with LASIK Flap Autograft and Penetrating Keratoplasty: A Case Report

Abstract

Introduction

This case report describes a rare case of fungal keratitis following femtoLASIK. Despite targetted antifungal therapy, this case necessitated an innovative surgical approach to manage an unexpected corneal perforation.

Case Presentation

A 35-year-old male presented 3 weeks post-femtoLASIK for myopic astigmatism with discomfort and reduced vision in his right eye. He was diagnosed with fungal keratitis surgery caused by Purpureocillium lilacinum and was treated with a myriad of therapy. Unfortunately, the patient developed corneal perforation during flap lift and flap bed irrigation. An innovative approach involving a tectonic autograft using a viable LASIK flap, followed by prompt penetrating keratoplasty, was utilised.

Conclusion

This technique was effective and able to mitigate the progression to an open globe.

Introduction

Microbial keratitis is a rare but dreaded complication of refractive surgery [1]. Fungal keratitis is associated with severe decline in visual acuity [1, 2]. Notably, Purpureocillium sp.-induced fungal keratitis often necessitates corneal transplantation, owing to poor outcomes [3, 4]. We report a case of Purpureocillium lilacinum-induced keratitis after femtosecond LASIK, where unresponsiveness to antifungal therapy mandated a tectonic patch autograft using a viable LASIK flap and subsequent prompt penetrating keratoplasty within a brief 2-week period from the initial presentation. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000538062).

Case Presentation

A 35-year-old male underwent femtoLASIK for myopic astigmatism and was prescribed topical antibiotics and steroid eye drops for 2 weeks post-procedure. Three weeks post-femtoLASIK, he presented with discomfort and blurred vision in his right eye. Clinical assessment revealed an unaided visual acuity of 6/24 in the affected eye, accompanied by a central corneal infiltrate measuring less than 1 mm in diameter and an overlying pinpoint epithelial defect (Fig. 1). The initial scraping procedure yielded a negative result. The patient was initiated on hourly topical fluoroquinolone therapy with 0.3% ofloxacin.

Fig. 1.

Central corneal infiltrate on initial presentation.

On the third day after the initial presentation, signs of deterioration, such as slightly larger and fuzzy infiltrate margins with inflammatory cells at the interface, were noted, prompting the decision to lift the LASIK flap and wash the interface with antibiotics while simultaneously obtaining additional specimens for microscopy and culture. Given the lack of response to topical 0.3% ofloxacin, topical 1% vancomycin was added onto the treatment regime. The subsequent scrape returned a positive result, confirming the presence of Purpureocillium lilacinum as the causative organism (Fig. 2). Antifungal susceptibility testing generated the following minimum inhibitory concentrations: amphotericin B >8 mg/L, isavuconazole 0.5 mg/L, posaconazole 0.5 mg/L, voriconazole 0.25 mg/L, and itraconazole 1.0 mg/L. Thus, indicating that the fungal is highly sensitive to voriconazole.

Fig. 2.

Microscopy showing erect conidiophores with densely clustered, tapered phialides that gave rise to chains of ellipsoid conidia were highly suggestive of Purpureocillium lilacinum.

Soon after administration of hourly 1% voriconazole, systemic therapy of oral voriconazole was initiated with loading dose of 400 mg twice daily followed by maintenance dose of 200 mg twice daily, targeting a trough level of 3–5.5 mg/L. Consequently, the patient underwent two additional LASIK flap lifts accompanied by voriconazole washes, driven by the absence of discernible clinical improvement. An early manifestation of endothelial plaque formation on the corneal endothelium was observed at the 1-week mark, a finding corroborated by anterior segment optical coherence tomography (Fig. 3). In response, a regimen of systemic voriconazole was initiated with ongoing monitoring of systemic drug levels to ensure the maintenance of a minimum concentration of 3 mg/mL.

Fig. 3.

Anterior segment optical coherence tomography demonstrating endothelial plaque formation on the corneal endothelium.

A few days later, the patient returned to the operating theatre for a planned flap amputation and intrastromal voriconazole injection. While lifting the flap, unexpected stromal perforation was encountered, necessitating prompt intervention. Given the unavailability of fresh corneal tissue and limited cyanoacrylate efficacy, a tectonic graft was crafted from patient’s amputated LASIK flap. The LASIK flap was amputated at the hinge, flush at the residual stromal bed, utilising Westcott scissors. Subsequently, the amputated flap was carefully positioned on a Teflon block, and the visibly infiltrated area was delineated with a surgical marker. To create a patch graft, a 4-mm skin biopsy punch was employed, targeting the clear area of the flap. This graft was then affixed onto the perforated residual stromal bed using fibrin glue and further reinforced with 7, 10-0 nylon sutures (Fig. 4), effectively covering the perforation.

Fig. 4.

LASIK flap secured in place using cyanoacrylate glue and interrupted sutures.

Penetrating keratoplasty was performed 2 days thereafter utilising high-quality donor tissue and simultaneous intracameral voriconazole injection. Both systemic and topical voriconazole regimens were continued for two and 3 months, respectively, after penetrating keratoplasty. There were no instances of infection recurrence (Fig. 5). At the 3-month postoperative mark, the patient’s unaided visual acuity improved to 6/18, correcting for the best corrected visual acuity of 6/12.

Fig. 5.

Anterior segment photograph after penetrating keratoplasty demonstrating clear cornea with no recurrence of infiltrate.

Discussion

Keratorefractive surgery is commonly performed and is associated with high patient satisfaction rates [5]. The incidence of microbial keratitis following refractive surgery is relatively low but displays significant variation, with reported rates ranging from 0% to 0.15% per procedure in a major review [1]. To our knowledge, this is the first report of post-refractive surgical microbial keratitis caused by Purpureocillium lilacinum. We also describe a unique approach utilising a corneal autograft derived from the amputated LASIK flap to address an unexpected perforation. The limitation of this case report is that it was a single case study and suffers from the limited possibility of generalising the validity of the technique in other cases.

Purpureocillium lilacinum, previously known as Paecilomyces lilacinus, is a soil saprophyte ubiquitously present in the environment [6]. This hyaline mould can cause disease in both immunocompetent and immunocompromised patients, leading to clinical syndromes such as pulmonary, skin, soft tissue, and endovascular infections [6]. Although standardised antifungal breakpoints are lacking, voriconazole minimum inhibitory concentration falls within the wild-type distribution in this case [7]. Notably, despite adequate topical and systemic voriconazole treatment, no clinical improvement was observed.

Managing corneal perforations encompasses a range of techniques including tissue adhesion, conjunctival flaps, amniotic membrane transplantation, Tenon’s patch graft, and keratoplasty [8]. Amniotic membrane transplantation combined with conjunctival flap covering surgery has been described to be a method for treatment of corneal perforations in fungal keratitis [9]. It appears to achieve good outcomes; however, it is associated with corneal neovascularisation and longer visual penalisation. Long-term outcomes are indeterminate and difficult to predict as there are no comparative studies, and the case counts are low. Case series conducted by Bhandari et al. [10] showcased the utilisation of small incision lenticule extraction-derived glued lenticule patch grafts for managing micro-perforations and intricate corneal defects. It is crucial to acknowledge that the refractive lenticules employed in this approach exhibit distinct structural and compositional characteristics when compared to LASIK flaps. Moreover, it is noteworthy that our specific case entails an autograft employing the LASIK flap, presenting a notable departure from the use of allografts. In our context, owing to the unavailability of fresh corneal tissue or amniotic membranes, we employed a novel technique. This approach involves the utilisation of the corneal epithelium and stroma from a viable LASIK flap as a patch graft. This strategy-maintained globe integrity affords us the time to procure a high-quality corneal graft and plan for elective penetrating keratoplasty, thereby mitigating the potential adverse consequences of an open globe.

Statement of Ethics

This case report conforms to the principles of the Declaration of Helsinki 2013. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images. Ethical approval was not required for this study in accordance with the local or national guidelines.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

This research received no specific grants from any funding agency in the public, commercial, or not-for-profit sectors.

Author Contributions

J.L. wrote the manuscript and performed a literature review of the case reports. Y.S., H.G., and G.B. supervised the writing and submission of this case report. The patient received direct clinical care for J.L., Y.S., H.G., and G.B., J.L., Y.S., H.G., and G.B. reviewed the manuscript before submission.

Funding Statement

This research received no specific grants from any funding agency in the public, commercial, or not-for-profit sectors.

Data Availability Statement

All data generated or analysed during this study are included in this article and its online supplementary material. Further enquiries can be directed to the corresponding author.