Safety of retrocorneal plaque aspiration for managing fungal keratitis

Postoperative Fungal Keratitis Managed by Anterior Chamber Washout and Intracameral Amphotericin-B: A Report of Two Cases

Keratomycosis is a significant cause of mono-ocular blindness, especially in tropical regions. Fungal keratitis developing in corneal incisions is very rare. We report the experience of treating two patients diagnosed with recalcitrant candida keratitis post-phacoemulsification with anterior chamber washout and deep debridement. The first patient was a 68-year-old woman who underwent left eye phacoemulsification nine months ago with a postoperative best corrected visual acuity of 6/6. The second patient was a 73-year-old man who had uneventful right eye phacoemulsification six months prior with a postoperative best corrected visual acuity of 6/9. Both patients used topical steroids postoperatively for more than three months and noted a drop in vision. Both patients had deep stromal infiltration and endothelial plaque at the primary corneal wound. They were unresponsive to topical, intracameral, and systemic antifungal therapy. Both patients underwent anterior chamber evacuation of hypopyon and endothelial plaque removal. Evacuation of hypopyon and removal of endothelial plaque was done with a 23G vitrectomy cutter using a low-powered vacuum controlled at 200 mmHg. The fluid inside the tubing was sent for culture analysis. We used viscoelastic coating on the endothelium to minimize the damage during the operations. Intracameral amphotericin B 15 µg/0.1 ml was given at the end of the operation. Postoperatively, both patients had clear corneas. The first patient’s visual acuity improved 6/18, and the second patient’s visual acuity improved to 6/9. Both cultures isolated Candida parapsilosis sensitive to amphotericin. These patient cases highlight that evacuation of the anterior chamber infiltration in recalcitrant fungal keratitis and intracameral injection of amphotericin B can be an effective adjuvant therapy.

Endothelial Biopsy for the Diagnosis and Management of Culture-Negative Retrocorneal Fungal Keratitis With the Assistance of Optical Coherence Tomography Imaging

PURPOSE

To report a case of a culture-negative deep fungal corneal infection that was diagnosed after histopathology of an anterior segment optical coherence tomography-guided endothelial biopsy.

METHODS

A 22-year-old woman with history of contact lens wear and concomitant topical steroid use presented with a mid-stromal corneal infiltrate that failed to respond to oral acyclovir and topical fortified antibiotics. Although cornea stains, cultures, and confocal microscopy showed negative results, there was high clinical suspicion for fungal keratitis. After 2 months on topical natamycin, oral voriconazole, and serial intrastromal and intracameral voriconazole injections, the infiltrate enlarged and deepened. Imaging with anterior segment optical coherence tomography revealed that the infection had progressed to an endothelial plaque.

RESULTS

Diagnostic endothelial biopsy was performed in the operating room. Cultures showed again negative results, whereas histopathology of the removed specimen revealed fungal elements. The postoperative edema at the site of the biopsy resolved over the course of 4 weeks, and a posterior stromal scar formed. Serial intrastromal and intracameral voriconazole injections were continued for the first postoperative month. At the 1-year and the 3-year follow-up examinations, the patient's vision was 20/20 without recurrence.

CONCLUSIONS

Intraoperative scraping of the endothelial plaque and histopathologic evaluation of the specimen proved to be of utmost importance for definitive diagnosis and resolution of the culture-negative deep fungal infection in this case. This young patient's cornea was retained and vision remains excellent.

Comparison of Safety and Efficacy of Intrastromal Injections of Voriconazole, Amphotericin B and Natamycin in Cases of Recalcitrant Fungal Keratitis: A Randomized Controlled Trial

Objective

To compare the safety and efficacy of intrastromal voriconazole (IS-VCZ), amphotericin B (IS-AMB) and natamycin (IS-NTM) as an adjunct to topical natamycin (NTM) in cases of recalcitrant fungal keratitis.

Design

Prospective randomized trial.

Setting

Tertiary eye centre.

Participants

Sixty eyes of 60 patients with microbiologically proven recalcitrant fungal keratitis (ulcer size >2 mm, depth >50% of stroma, and not responding to topical NTM therapy for two weeks) were recruited.

Methods

patients were randomized into three groups of 20 eyes, each receiving ISVCZ 50ug/0.1 mL, ISAMB, 5ug/0.1 mL and ISNTM 10ug/0.1 mL (prepared aseptically in ocular pharmacology). The patients in all three groups continued topical NTM 5% every four hours until the ulcer healed. Primary outcome measure was time taken till complete clinical resolution of infection, and secondary outcome measure was best corrected visual acuity (BCVA) at six months.

Results

All three groups had comparable baseline parameters. The mean duration of healing was significantly better (p=0.02) in the ISNTM group (34±5.2 days) as compared to the ISVCZ group (36.1±4.8 days) and the ISAMB group (39.2±7.2 days). About 95%, 90% and 95% patients healed successfully in the ISVCZ, ISAMB and ISNTM groups, respectively. In terms of healing, deep vascularization was significantly greater in the ISAMB group (55%, p=0.02) when compared to the ISVCZ and ISNTM groups (31% and 26%, respectively). There were fewer repeat injections in the ISNTM group (7/20 vs 8/20 and 9/20 in the ISVCZ and ISNTM groups, respectively).

Conclusion

Intrastromal injections are a safe and effective adjunct to conventional therapy in the management of recalcitrant fungal keratitis. ISNTM had a similar visual outcome with faster healing while ISAMB had a higher rate of deep vascularization after healing.

Update on the management of fungal keratitis

PURPOSE

The aim of this article is to introduce the recent advance on the studies of fungal keratitis published over past 5 years.

METHODS

We performed literature review of articles published on PubMed, Google Scholar, CNKI and Web of Science relevant to the diagnosis, pathogenesis and novel treatment of fungal keratitis.

RESULTS

Excessive inflammation can lead to stromal damage and corneal opacification, hence the research on immune mechanism provides many potential therapeutic targets for fungal keratitis. Many researchers discussed the importance of earlier definitive diagnosis and were trying to find rapid and accurate diagnostic methods of pathogens. Develop new drug delivery systems and new routes of administration with better corneal penetration, prolonged ocular residence time, and better mucoadhesive properties is also one of the research hotspots. Additionally, many novel therapeutic agents and methods have been gradually applied in clinical ophthalmology.

CONCLUSION

The diagnosis and treatment of fungal keratitis are still a challenge for ophthalmologist, and many researches provide new methods to conquer these problems.