Treatment with intrastromal and intracameral voriconazole in 2 eyes with Lasiodiplodia theobromae keratitis: case reports

Favorable outcome of Lasiodiplodia theobromae keratomycosis : a clinical case and systematic review

BACKROUD

Keratitis caused by Lasiodiplodia theobromae is rare and typically associated with a poor prognosis. Current literature lacks sufficient evidence on effective management of patients with this condition.

CASE PRESENTATION

A 74-year-old former agricultural worker presented with a red right eye, discomfort, and decreased visual acuity, progressing over three days without treatment. Examination revealed type 2 diabetes and a non-perforating, spiculated corneal abscess with a hypopyon in the right eye. Initial treatment included a triple antibiotic therapy and supportive care. Direct mycological examination identified numerous septate mycelial filaments. Antifungal treatment with natamycin and voriconazole, both topically and orally, was initiated. Cultures confirmed Lasiodiplodia theobromae. The patient showed significant improvement. Treatment continued for eight weeks, with a final visual acuity of 20/50 due to a stromal scar.

CONCLUSION

An extensive literature review conducted in November 2023, using databases such as PubMed and Google Scholar with the keywords "lasiodiplodia" and "keratitis" yielded no previous cases of this specific condition being managed solely with the combined use of natamycin and voriconazole. This antifungal combination is commonly included in most management protocols for fungal keratitis. Factors such as the use of corticosteroids and delayed diagnosis were noted to adversely affect the prognosis. This case and this systematic review underscores the potential for non-surgical management options in severe fungal keratitis.

Lasiodiplodia theobromae keratitis: A rare tropical fungal keratitis in a non-tropical climate

Purpose

We present the clinical and histopathological findings of a geographically unique Lasiodiplodia theobromae fungal keratitis case in North Carolina. L. theobromae is a rare cause of fungal keratitis, and all but one of the 51 previously reported cases have occurred in patients living in the tropics.

Observations

A man in his early 50s developed L. theobromae keratitis after being struck in the left eye by a piece of debris while using a flexible-cord weed trimmer. Intracapsular lensectomy and penetrating keratoplasty were necessary when initial antimicrobial therapy was ineffective. The best-corrected visual acuity was 20/40 four years postoperatively.

Conclusions and Importance

Our patient is only the second example of L. theobromae keratitis in a patient living in a sub-tropical climate and the first case in the U.S.A. outside of Florida. Additional in-vitro antibiotic sensitivity testing and documentation of more clinical cases are needed to define the optimal therapy for Lasiodiplodia theobromae keratitis.

Toxicity of simultaneous intrastromal and intracameral injection of voriconazole on corneal endothelium in a rabbit model

PURPOSE

To investigate the toxicity of repeated simultaneous intrastromal and intracameral injections of voriconazole in corneal endothelial cells in a rabbit model.

METHODS

Thirty-six eyes of 18 New Zealand white rabbits (six eyes per group) were divided into 6 groups according to the concentration of voriconazole (Group A, 0%; Group B, 0.05%; Group C, 0.1%; Group D, 0.25%; Group E, 0.5%; Group F, 1%). A combination of intrastromal and intracameral voriconazole injections were administrated to the eyes of each group three times on days 0, 3, and 7. Corneal clouding grades and central corneal thickness (CCT) were examined on days 0, 3, 7, 10, and 14. The endothelial cell counts (ECC) were measured on days 0 and 14. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed on day 14.

RESULTS

Group F (1%) showed more severe corneal clouding than the other groups (Groups A-E) from day 7 (p < 0.05, respectively). There were no significant differences in CCT and ECC among the six groups at any time point (p > 0.05, respectively). SEM revealed blurring of the cell border and loss of microvilli at concentrations ≥0.25% (Groups D-F). TEM revealed microstructural changes in endothelial cells at concentrations ≥0.1% (Groups C-F), and multiple vacuoles were observed at a concentration of 1% voriconazole (Group F).

CONCLUSIONS

Repeated simultaneous intrastromal and intracameral voriconazole injections at a concentration of 0.1% or higher induced microstructural endothelial damage in rabbit corneal endothelial cells.

Elucidating the clinical, microbiological and molecular diagnostic aspects of Macrophomina phaseolina keratitis

This study reports the clinico-microbiological features of Macrophomina phaseolina keratitis. Clinically diagnosed as microbial keratitis, six patients underwent microbiological evaluation. Fungal culture isolates from cornea were subjected to DNA sequencing of the ITS region, phylogenetic analysis and reconfirmation by polymerase chain reaction (PCR). Minimum inhibitory concentrations (MICs) of six antifungal drugs were determined by microbroth dilution method against the six isolates. All patients were treated with antifungals. Failed medical therapy necessitated therapeutic penetrating keratoplasty (TPK). Corneal buttons were processed for histopathology. In all patients, the corneal scraping showed septate hyaline fungal filaments. The BLAST analysis for ITS sequences of all six fungal isolates suggested M. phaseolina, however, when limited to sequences from type material, they matched M. pseudophaseolina. Phylogenetic analysis could not differentiate between these two species and clustered in a single clade. PCR assay of specific gene sequence [MpCal (calmodulin)] reconfirmed all isolates as M. phaseolina. The MICs of voriconazole and posaconazole were lowest (0.03 to 2 and 0.1 to 2µg/mL respectively) and all isolates were susceptible to natamycin. Except for case 1, which healed with a scar on treatment, all other cases worsened, despite medical treatment, necessitating TPK. Histopathology of 3 out of 4 buttons showed the presence of fungal filaments. While direct microscopic examination of corneal scrapings is helpful in diagnosis, identification of M. phaseolina in culture is challenging. Although MICs of commonly used antifungals are low response to medical therapy is not encouraging; patients may require TPK for resolution of infection in M. phaseolina keratitis.

Voriconazole-impregnated multilayered AMT and intracorneal plus intracameral injection in recalcitrant fungal corneal ulcer

We describe the management of a referred man in his 50s with corneal ulcer in the left eye. Slit-lamp biomicroscopy revealed an infiltrate (4.5×3.5 mm), involving full corneal thickness, corneal melt less than one-third corneal thickness and hypopyon (3.0 mm). Branched septate hypha on direct microscopy and Aspergillus flavus in Sabaraud's dextrose agar confirmed the clinical diagnosis of fungal corneal ulcer. We used natamycin 5% suspension 1 hourly, voriconazole 1% 1 hourly, gatifloxacin 0.5% three times and atropine 1% three times per day, for 2 weeks. However, there was no improvement and the corneal melt increased. We used intracameral plus intracorneal voriconazole injection with voriconazole-impregnated amniotic membrane transplant. We observed a significant decrease in conjunctival congestion, size/depth of infiltrate and hypopyon at the first week of antifungal therapy. Subsequently, at 6 weeks, corneal infiltrate had decreased and superficial corneal vascularisation appeared. Later, at 12 weeks, the patient developed corneal opacity.

The Clinical Features and Prognostic Factors for Treatment Outcomes of Dematiaceous Fungal Keratitis over 9 Years at a Tertiary Eye Care in Northern Thailand

Dematiaceous fungal keratitis is an important etiology of visual loss, particularly in an agricultural society. From a retrospective review of medical records from 2012 to 2020, 50 keratitis cases of cultured-positive for dematiaceous fungi were presented at a tertiary care hospital in Northern Thailand. The study aimed to identify the isolated causative dematiaceous species using the PCR technique and to explore their related clinical features, including treatment prognoses. Sequencing of the amplified D1/D2 domains and/or ITS region were applied and sequenced. Of the 50 dematiaceous fungal keratitis cases, 41 patients were males (82%). In most cases, the onset happened during the monsoon season (June to September) (48%). The majority of the patients (72%) had a history of ocular trauma from an organic foreign body. The most common species identified were Lasiodiplodia spp. (19.35%), followed by Cladosporium spp. and Curvularia spp. (12.90% each). About half of the patients (52%) were in the medical failure group where surgical intervention was required. In summary, ocular trauma from an organic foreign body was the major risk factor of dematiaceous fungal keratitis in Northern Thailand. The brown pigmentation could be observed in only 26%. Significant prognostic factors for medical failure were visual acuity at presentation, area of infiltrate, depth of the lesions, and hypopyon.

Efficacy of adjuvant intrastromal and combination of intrastromal and intracameral voriconazole in <em>Aspergillus fumigatus</em>-induced moderate fungal keratitis in rabbits

BACKGROUND There is no in vivo evidence for the effectiveness of adjuvant intrastromal and combination of intrastromal and intracameral voriconazole (VCZ) for treating Aspergillus fumigatus keratitis. This study aimed to compare the efficacy of both agents against it.  METHODS A randomized, masked, controlled experimental study was conducted on 11 albino New Zealand white rabbits in which moderate fungal keratitis was induced by inoculating spores of A. fumigatus to the cornea. The rabbits were allocated into 3 groups: 50 μg/0.1 ml intrastromal VCZ injection, 50 μg/0.1 ml intrastromal VCZ and intracameral VCZ injections, and topical VCZ (control). The treatment was given 5 days after inoculation. Epithelial defect, infiltrate size, corneal ulcer depth, and hypopyon were evaluated clinically. Histopathological and mycological examinations were also done 14 days after treatment.  RESULTS All rabbits in the adjuvant treatment groups demonstrated a tendency of a better clinical response with decreasing size of epithelial defect (p = 0.679) and infiltrate (p = 0.755) than in the control group. Direct microscopy, corneal culture, and chop corneal tissue culture were still positive in most of the rabbits from all groups. Histopathological examination showed an increase of inflammatory cells after treatment in all groups, especially in rabbits which were inoculated with A. fumigatus spores in both eyes.  CONCLUSIONS An adjuvant combination of intrastromal and intracameral VCZ showed a tendency of better clinical response for A. fumigatus-induced moderate fungal keratitis in rabbits. 

Intrastromal voriconazole: An adjuvant approach for recalcitrant mycotic keratitis

Purpose:

To evaluate the efficacy of intrastromal voriconazole for the management of fungal keratitis not responding to conventional therapy.

Methods:

Patients having microbiologically proven fungal keratitis with poor response to 2 weeks of conventional topical therapy were included in the study. After obtaining informed consent, an intrastromal injection of voriconazole was administered around the ulcer. Response to treatment in the form reduction in the size of the ulcer and infiltration was recorded on regular follow-ups.

Results:

Out of a total of 20 patients, 14 responded to intrastromal treatment and resolved, whereas six patients progressed to perforation. Mean resolution time was 35.5 ± 9.2 days. The most common organism isolated was Fusarium in six patients while Aspergillus and Mucor were isolated in two each. The causative organism could not be isolated in eight patients. The size of the ulcer at presentation and height of hypopyon were found to be significant risk factors associated with treatment outcomes.

Conclusion:

Intrastromal voriconazole as an adjuvant therapy appeared to be effective in treatment of fungal keratomycosis not responding to conventional therapy, thus, reducing the need for therapeutic or tectonic keratoplasty.

Histological Effects of Intravitreal Injection of Antifungal Agents in New Zealand White Rabbits: An Electron Microscopic and Immunohistochemical Study

Fungal endophthalmitis is a serious and vision-threatening infection which requires an immediate and effective treatment approach. Our research aims to elucidate the histological effects of the intravitreal injection of the maximum safe dosage of voriconazole and micafungin on retina. Six albino New Zealand White Rabbits were used. In experimental animals, a solution of voriconazole (Group V) or micafungin (Group M) was intravitreally injected in the right eye, while in control animals, balanced salt solution was intravitreally injected in the left eye (Group C). Euthanasia was performed ten days post injection and the retina was removed and prepared for histological examination with a light and electron microscope. Eosin-hematoxylin staining did not reveal any pathological changes in any of the samples examined. The immunohistochemical staining for Tumor Necrosis Factor alpha (TNF-a) marker was detected as negative in all samples, while Interleukin 6 (IL-6) marker was detected as mild only in the group injected with voriconazole. Electron microscopy revealed several ultrastructural alterations in retinal layers in both groups of experimental animals. Histological retinal lesions, revealed with electron microscopy in the present investigation, raises the question of the safe usage of these antifungal agents in the treatment of fungal intraocular infections in the future.

Effect of γ-Aminobutyric Acid (GABA) on the Metabolome of Two Strains of Lasiodiplodia theobromae Isolated from Grapevine

The effect of γ-aminobutyric acid (GABA) on the metabolome of two strains of Lasiodiplodia theobromae isolated from grapevine that hold a different degree of virulence to the host plant (LA-SOL3 (more virulent), LA-SV1 (less virulent)) was investigated. The culture filtrates and crude extracts from the two strains grown in the presence and absence of 10 mM of GABA were tested for phytotoxicity on tomato plant cuttings and leaves, respectively. Considering the opportunistic nature of this fungus for humans, crude extracts were also tested for cytotoxicity on mammalian cell lines. We found that culture filtrates and crude extracts have a decreased toxicity in the presence of GABA. Metabolomic analysis, conducted on both strains at both growth conditions, revealed the production of several compounds, such as indole-3-carboxylic acid (ICA, which is the main compound produced by L. theobromae), 3-indolecarboxyaldehyde, (3R,4S)-botryodiplodin, (R)-mellein. Finally, data demonstrate that GABA both induces a decrease in the amount of ICA, and a diversification of the metabolites produced by L. theobromae.

Secondary Metabolites of Lasiodiplodia theobromae: Distribution, Chemical Diversity, Bioactivity, and Implications of Their Occurrence

Lasiodiplodia theobromae is a plant pathogenic fungus from the family Botryosphaeriaceae that is commonly found in tropical and subtropical regions. It has been associated with many hosts, causing diverse diseases and being responsible for serious damages on economically important crops. A diverse array of bioactive low molecular weight compounds has been described as being produced by L. theobromae cultures. In this review, the existing literature on secondary metabolites of L. theobromae, their bioactivity, and the implications of their occurrence are compiled. Moreover, the effects of abiotic factors (e.g., temperature, nutrient availability) on secondary metabolites production are highlighted, and possible avenues for future research are presented. Currently, a total of 134 chemically defined compounds belonging to the classes of secondary metabolites and fatty acids have been reported from over 30 L. theobromae isolates. Compounds reported include cyclohexenes and cyclohexenones, indoles, jasmonates, lactones, melleins, phenols, and others. Most of the existing bioactivity studies of L. theobromae metabolites have assessed their potential phytotoxic, cytotoxic, and antimicrobial activities. In fact, its host adaptability and its ability to cause diseases in plants as well as in humans may be related to the capacity to produce bioactive compounds directly involved in host–fungus interactions.

Fungal keratitis: Pathogenesis, diagnosis and prevention

As a kind of serious, potentially sight-threatening corneal infections with poor prognosis, fungal keratitis can bring a heavy economic burden to patients and seriously affect the quality of life, especially those in developing countries where fungal keratitis is more prevalent. Typical clinical features include immune rings, satellite lesions, pseudopods, hypha moss, hypopyon and endothelial plaques. The ideal therapeutic effects could not be achieved by current treatments for many reasons. Therefore, under the current status, understanding the pathogenesis, early diagnosis and prevention strategies might be of great importance. Here, in this review, we discuss the recent progresses that may advance our understanding of pathogenesis, early diagnosis and prevention of fungal keratitis.

Incidence of recurrent fungal keratitis after primary keratoplasty and visual outcome and prognosis after intervention for the recurrence

There are no standardized protocols or guidelines for the treatment of recurrent fungal keratitis after therapeutic keratoplasty. This study aimed to investigate the incidence of recurrent fungal keratitis after the primary keratoplasty and the visual outcome and prognosis after intervention for the recurrence.This was a retrospective study. Patients with recurrent fungal keratitis after lamellar keratoplasty (LK) or penetrating keratoplasty (PK) were treated with different antifungal regimens at Shandong Eye Hospital and Qingdao Eye Hospital between Januray 2004 and December 2015. The operative techniques included PK, focal excision, tectonic keratoplasty with a patch graft, lensectomy and vitrectomy, and combined operation. Patients were followed at 1, 2, and 3 months, and then every 6 months after surgery for 2 years. Best corrected visual acuity was assessed and recurrence was recorded. Good prognosis was defined as the presence of visual acuity.Fungal keratitis recurred in 112 of 1448 patients (112/1448, 7.7%) treated initially with PK or LK. The good prognosis rates for different sites of recurrent fungal keratitis were: overall, 93 of 112 (83.0%); recipient bed, 64 of 69 (92.8%); anterior chamber, 14 of 14 (100%); posterior segment, 10 of 16 (62.5%); and atypical, 5 of 13 (38.5%). There was no significant difference in the timing of recurrence between the good and poor prognosis groups (P = .518). Recurrence rates were similar between patients with PK (8.6%) and those with LK (6.0%; P > .05), but the good prognosis rate in patients with post-LK recurrence (96.8%) was higher than that in patients with post-PK recurrence (77.8%, P = .017).Individualized treatment according to recurrent sites of fungal keratitis can achieve a good prognosis in most patients.

Antifungal Susceptibility, Morphological and Molecular Characterization of Lasiodiplodia theobromae Isolated from a Patient with Keratitis

Lasiodiplodia theobromae is a rare ocular pathogen. We report a patient with fungal keratitis caused by L. theobromae. The patient was a 75-year-old male, a farmer with diabetes type II, and no previous history of ocular trauma. Histopathology analysis revealed the presence fungi invading Descemet's membrane of the cornea. The fungus was characterized by septate, highly bulged fungal filaments involving full corneal thickness in the corresponding histopathology specimens. A dematiaceous mold was isolated and initally identified as L. theobromae by microscopic and macroscopic morphology, and further confirmed by PCR-based determination of internal transcribed spacer (ITS) regions of ribosomal DNA. Antifungal susceptibility tests showed sensitivity to amphotericin B (AMB) and voriconazole ( VRC), and resistance to other azoles, including itraconazole (ITC) and fluconazole (FLC). Corneal transplant was performed. Despite in vitro itraconazole resistance, the patient was successfully treated with oral itraconazole, topical voriconazole and natamycin, combined with ocular injections of amphotericin B and voriconazole.

Recent advances in diagnosis and management of Mycotic Keratitis

Mycotic keratitis is a major cause of corneal blindness, especially in tropical and subtropical countries. The prognosis is markedly worse compared to bacterial keratitis. Delayed diagnosis and scarcity of effective antifungal agents are the major factors for poor outcome. Over the last decade, considerable progress has been made to rapidly diagnose cases with mycotic keratitis and increase the efficacy of treatment. This review article discusses the recent advances in diagnosis and management of mycotic keratitis with a brief discussion on rare and emerging organisms. A MEDLINE search was carried out for articles in English language, with the keywords, mycotic keratitis, fungal keratitis, emerging or atypical fungal pathogens in mycotic keratitis, investigations in mycotic keratitis, polymerase chain reaction in mycotic keratitis, confocal microscopy, treatment of mycotic keratitis, newer therapy for mycotic keratitis. All relevant articles were included in this review. Considering the limited studies available on newer diagnostic and therapeutic modalities in mycotic keratitis, case series as well as case reports were also included if felt important.

Molecular and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based Characterization of Clinically Significant Melanized Fungi in India

Melanized or black fungi are a heterogeneous group of fungi causing cutaneous to systemic diseases with high mortality. These fungi are rarely reported as agents of human infections, primarily due to difficulties in their classical identification. In this study, we examined, using molecular methods and matrix-assisted laser desorption ioniazation-time of flight mass spectrometry (MALDI-TOF MS), the diversity of melanized fungi (MF) isolated from patients in 19 medical centers in India. Overall, during a 4-year period, 718 (5.3%) clinical specimens yielded MF. Of these, 72 (10%) isolates had clinical significance and were identified primarily by sequencing the internal transcribed spacer and large subunit (LSU) regions. MF represented 21 genera comprising 29 species, the majority of them belonging to the orders Pleosporales (50%) and Chaetothyriales (22%). Among the 29 fungal species identified in this study, only 6 (20%) species were identified by the MALDI-TOF MS due to the limited commercial database of Bruker Daltonics for MF. However, a 100% identification rate of 20 additional species identified in this study was obtained by constructing an in-house database using 24- to 96-h-old liquid cultures. Further, the CLSI broth microdilution method revealed low MICs for posaconazole (≤1 μg/ml) and voriconazole (≤2 μg/ml) in 96% and 95% of isolates, respectively. Skin/subcutaneous and sino-nasal and pulmonary phaeohyphomycosis due to MF were diagnosed in 21.4% (n = 15) and 28.5% (n = 20) of cases. Also, 10% of patients had central nervous system involvement (n = 7), and 3 cases of fungal osteomyelitis due to Cladophialophora bantiana and Corynespora spp. were observed.

Review of clinical and basic approaches of fungal keratitis

Fungal keratitis (FK) is a serious disease which can cause blindness. This review has current information about the pathogenesis, limitations of traditional diagnosis and therapeutic strategies, immune recognition and the diagnosis and therapy of FK. The information of this summary was reviewed regularly and updated as what we need in the diagnosis and therapy of FK nowadays.

Successful Treatment of Lasiodiplodia theobromae Keratitis - Assessing the Role of Voriconazole

Purpose

The aim of this paper is to report the successful management of the first case of Lasiodiplodia theobromae keratitis in Hong Kong.

Methods

We conducted a case report.

Results

A 43-year-old Chinese male with a history of diabetes developed left eye keratitis after a trauma during tree felling. Fungal keratitis was diagnosed using a confocal microscope on day 1, and L. theobromae was confirmed from the culture. He was given oral voriconazole, topical natamycin, and topical and intracameral amphotericin B. The patient's condition improved after the initial treatment. However, there was a slow progression to descemetocele formation and impending perforation due to corneal melting. Penetrating keratoplasty was performed at 8 weeks after presentation. Final visual recovery was good with no recurrence of infection. The cornea remained clear.

Conclusions

We report the first case of L. theobromae keratitis in Hong Kong, and it is the only case so far that involved the use of oral voriconazole in the combination therapy. Early recognition with the aid of confocal microscopy allowed the early start of treatment. The use of newer antifungal voriconazole topically and orally combined with topical amphotericin B appeared to be useful in the eradication of the fungus and prevention of recurrence. Intracameral antifungals might have improved the clinical management.

Invasive Fungal Sinusitis by Lasiodiplodia theobromae in an Patient with Aplastic Anemia: An Extremely Rare Case Report and Literature Review

Human Lasiodiplodia theobromae infection has not been reported frequently. We report the first case of invasive L. theobromae nasal and neck infection. A 66-year-old male visited our hospital with anemia and general weakness. He showed pancytopenia, and his bone marrow examination revealed markedly decreased hematopoietic cells. The patient was presumed to have iatrogenic aplastic anemia due to mushroom toxicity. He began treatment for multiple organ infections with broad-spectrum antibiotics and antifungal agents. During hospitalization, he complained of nasal obstruction and left neck lymph node enlargement. A mass-like lesion was observed, and a nasal mass biopsy was performed. The mass was identified as a fungal ball. He underwent surgical excision for the nasal mass and the neck lymph node. The pathologic examination indicated an invasive fungal infection, and the lymph node revealed chronic granulomatous inflammation with fungal infection. 18s rRNA sequencing revealed that the sequence shared 99 % identity with L. theobromae. The nasal mass fungus was identified by internal transcribed spacer region sequencing from pathologic paraffin sections. The obtained sequence corresponded to Lasiodiplodia or Macrophoma. The sequence corresponded to the neck discharge sequence results. Hence, the patient was diagnosed with invasive fungal sinusitis with neck lymph node involvement caused by L. theobromae. To our knowledge, this is the first report of L. theobromae infection in Korea and the first report of invasive L. theobromae fungal sinusitis in the literature. We should include more precise evaluations of additional novel fungal species as possible candidates.

Lasiodiplodia species fungal osteomyelitis in a multiple myeloma patient

Lasiodiplodia species are environmental fungi that have been reported as a cause of infection in both immunocompetent and immunocompromised patients. We present a case of fungal osteomyelitis caused by Lasiodiplodia species in a patient with multiple myeloma after autologous stem cell transplant. The patient was successfully treated with a combination of surgery and oral voriconzole. To the best of our knowledge, this is the first reported case of fungal osteomyelitis caused by Lasiodiplodia species.

Established and emerging ancillary techniques in management of microbial keratitis: a review

Microbial keratitis is a sight-threatening condition and an ocular emergency, because of the potential for rapid progression. Intensive topical antimicrobials are the mainstay and the gold standard of treatment for microbial keratitis. However, despite appropriate diagnosis and therapy, treatment failure is still common, and can result in significant morbidity due to corneal perforation and/or scarring. For this reason, clinicians continue to seek novel treatment techniques in order to expand the armamentarium of tools available to manage microbial keratitis, and in doing so improve clinical outcomes. In this review, we examine the evidence for some established, as well as a few emerging ancillary techniques used to manage microbial keratitis. These include topical corticosteroids, corneal collagen cross-linking, intrastromal antimicrobials, amniotic membrane transplantation and miscellaneous other techniques. Of these, collagen cross-linking shows some promise for selected cases of infectious keratitis, although more research in the area is required before it is accepted as mainstream treatment for this potentially blinding condition.