Resveratrol has neuroprotective effects and plays an anti-inflammatory role through Dectin-1/p38 pathway in Aspergillus fumigatus keratitis

PURPOSE

To determine the antifungal, anti-inflammatory and neuroprotective effects of resveratrol (RES) in Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Cytotoxicity assay and Draize eye assay were performed to assess the toxicity of RES. The antifungal effect of RES was assessed by minimal inhibitory concentration, scanning or transmission electron microscopy, propidium iodide uptake assay, and Calcofluor white staining. Phosphorylation of p38 MAPK, mRNA and protein levels of Dectin-1 and related inflammatory factors were measured by qRT-PCR, ELISA and Western blot in vitro and in vivo. Clinical score, HE staining, plate count, and myeloperoxidase test were used to observe the progress of fungal keratitis. IF staining, qRT-PCR, and the Von Frey test were selected to assess the neuroprotective effects of RES.

RESULTS

RES suppressed A. fumigatus hyphae growth and altered hyphae morphology in vitro. RES decreased the expression of Dectin-1, IL-1β and TNF-α, as well as p38 MAPK phosphorylation expression, and also decreased clinical scores, reduced inflammatory cell infiltration and neutrophil activity, and decreased fungal load. RES also protected corneal basal nerve fibers, down-regulated mechanosensitivity thresholds, and increased the mRNA levels of CGRP and TRPV-1..

CONCLUSION

These evidences revealed that RES could exert antifungal effects on A. fumigatus and ameliorate FK through suppressing the Dectin-1/p38 MAPK pathway to down-regulate IL-1β, IL-6, etc. expression and play protective effect on corneal nerves.

Cefiderocol Is an Effective Topical Monotherapy for Experimental Extensively Drug-Resistant Pseudomonas aeruginosa Keratitis

Purpose

To test cefiderocol, a siderophore-cephalosporin antibiotic for topical monotherapy treatment of experimental extensively drug-resistant (XDR) Pseudomonas aeruginosa keratitis.

Design

Preclinical study.

Subjects and Controls

Deidentified P. aeruginosa keratitis isolates, XDR P. aeruginosa from eye drop outbreak, rabbits, saline, cefiderocol 50 mg/ml, ciprofloxacin 0.3%, and tobramycin 14 mg/ml.

Methods Intervention or Testing

Cefiderocol antibacterial activity against P. aeruginosa keratitis isolates (n = 135) was evaluated by minimum inhibitory concentration (MIC) testing. Ocular toxicity/tolerability and antibacterial efficacy were tested in vivo with experimental rabbit models. Corneal concentrations and stability were assessed using a bioassay.

Main Outcome Measures

Minimum inhibitory concentration analysis for susceptibility, graded tests for ocular toxicity/tolerability, colony-forming unit (CFU) analysis for bacterial burden, corneal cefiderocol concentrations.

Results

One hundred percent of P. aeruginosa keratitis isolates were susceptible to cefiderocol (n = 135), the MIC90 was 0.125 μg/ml including the XDR isolate (MIC = 0.125 μg/ml). Topical cefiderocol 50 mg/ml was minimally toxic to the ocular surface and was well tolerated. For the XDR P. aeruginosa isolate, topical cefiderocol 50 mg/ml, significantly decreased corneal CFU compared with ciprofloxacin 0.3%, tobramycin 14 mg/ml, and saline. In addition, tobramycin 14 mg/ml was more effective than the saline control. Mean cefiderocol corneal concentrations were 191× greater than the MIC90 of the P. aeruginosa keratitis isolates. Refrigerated cefiderocol maintained antimicrobial activity over a 1-month period.

Conclusions

These results demonstrate that cefiderocol is well tolerated on rabbit corneas and is effective against P. aeruginosa keratitis isolates in vitro and was effective in vivo against an XDR isolate in a rabbit keratitis model. Given the recent outbreak of keratitis caused by this XDR P. aeruginosa, cefiderocol is a promising additional antibiotic that should be further evaluated for topical treatment of keratitis caused by antibiotic resistant P. aeruginosa.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Nigrospora oryzae causing human corneal keratitis: A case report

Purpose

We report a rare case of microbial keratitis caused by Nigrospora oryzae.

Observations

A 72-year-old Japanese woman was injured by plant debris and developed oval corneal ulcers and hypopyon in the anterior chamber. After 5 days, she complained of pain, redness, and vision loss in her left eye and was treated with antibacterial eye drops and an ointment (1.5 % levofloxacin hydrate, cefmenoxime hydrochloride, and sterilization and disinfection eye drops; SAN-IODE and ofloxacin ophthalmic ointment). Examination revealed a worsening oval corneal ulcer with Descemet's folds and a faint hypopyon. Considering the infection from soil or plants and the poor response to intensive antibacterial eye drops, topical antifungal eye drops, i.e., 1 % voriconazole eye drops, and 1 % natamycin ointment were applied. Direct microscopy of the corneal scraping with Gram staining was performed and the result was negative. Cultures from corneal scrapings showed the growth of dark colonies after several days. The colony was identified as Nigrospora oryzae by sequencing of the fungal internal transcribed spacer region. Pain and vision loss improved with improvement in corneal ulcers. The antifungal treatment was administered for 37 days. Discontinuation of the eye drops after 1 month did not result in keratitis recurrence. At the final follow-up at 70 days, the best-corrected visual acuity was 20/25, with persistent small corneal opacity.

Conclusions and importance

Here, we report a case of fungal keratitis caused by Nigrospora oryzae. Microbiological identification of the causes of rare infections is difficult in clinical laboratories, necessitating the use of advanced molecular techniques based on amplification and sequencing of appropriate phylogenetic markers. Nigrospora oryzae responds to topical voriconazole and natamycin.

Design and development of dual drug-loaded nanofibrous inserts for ophthalmic sustained delivery of AMK and VAN: Pharmacokinetic study in rabbit's eye

Bacterial corneal keratitis is a damage to the corneal tissue that if not treated, can cause various complications like severe vision loss or even blindness. Combination therapy with two antibiotics which are effective against Gram-positive and Gram-negative bacteria offers sufficient broad-spectrum antibiotic coverage for the treatment of keratitis. Nanofibers can be a potential carrier in dual drug delivery due to their structural characteristics, specific surface area and high porosity. In order to achieve a sustained delivery of amikacin (AMK) and vancomycin (VAN), the current study designed, assessed, and compared nanofibrous inserts utilizing polyvinyl alcohol (PVA) and polycaprolactone (PCL) as biocompatible polymers. Electrospinning method was utilized to prepare two different formulations, PVA-VAN/AMK and PCL/PVA-VAN/AMK, with 351.8 ± 53.59 nm and 383.85 ± 49 nm diameters, respectively. The nanofibers were simply inserted in the cul-de-sac as a noninvasive approach for in vivo studies. The data obtained from the physicochemical and mechanical properties studies confirmed the suitability of the formulations. Antimicrobial investigations showed the antibacterial properties of synthesized nanofibers against Staphylococcus aureus and Pseudomonas aeruginosa. Both in vitro and animal studies demonstrated sustained drug release of the prepared nanofibers for 120 h. Based on the in vivo findings, the prepared nanofibers' AUC0-120 was found to be 20 to 31 times greater than the VAN and AMK solutions. Considering the results, the nanofibrous inserts can be utilized as an effective and safe system in drug delivery.

Ocular manifestations of Monkeypox virus (MPXV) infection with viral persistence in ocular samples - a case series

OBJECTIVE

We describe the clinical presentation and ocular viral dynamics in patients with Monkeypox virus-related ophthalmic disease (MPXROD).

METHODS

In this case series, we investigated five consecutive patients with confirmed mpox, diagnosed through a positive Monkeypox virus (MPXV) Polymerase Chain Reaction (PCR) test and presenting with ocular symptoms. They were referred from the Reference Center for Sexually Transmitted Infections in São Paulo (CRT) to the Uveitis Sector at the Federal University of São Paulo, between August and December 2022. We performed PCR testing on ocular samples and culture supernatants for MPXV in all patients. Viral sequencing was conducted in one of the cases.

RESULTS

Replicating MPXV was identified in at least one ocular sample of all patients, between day 31 and day 145 after the onset of skin lesions. All patients presented with keratitis, 3 with uveitis (60%) and two exhibited hypopyon (40%). The onset of ocular symptoms occurred at a mean of 21,2 days after the appearance of the first skin lesion and persisted, on average, for 61,6 days, with a worsening trend observed until the initiation of tecovirimat treatment. Tecovirimat treatment was administered to all patients, with initiation occurring between 31 and 145 days after the onset of skin lesions. MPXV genome sequencing of an isolate from one patient classified it as belonging to lineage B1 in clade IIb.

CONCLUSION

This study reveals a late onset and persistence of sight threatening ocular disease, along with potential viral infectivity even after systemic resolution in mpox cases. These findings highlight the risk of ongoing transmission from individuals with prolonged ocular manifestations, particularly through ocular discharge.

In the eye of the ophthalmologist: the corneal microbiome in microbial keratitis

PURPOSE

To describe the bacterial findings by a targeted sequencing approach from corneal samples of patients with microbial keratitis and factors influencing culture outcome of indirectly inoculated corneal specimen.

METHODS

Prospective inclusion of patients fulfilling predefined criteria of microbial keratitis. Samples from the corneal lesion were collected and dispensed in liquid transport medium, from which both culture and targeted amplification and sequencing of the V3-V4 region of the 16S rRNA gene were carried out. Additional standard corneal culture from the corneal lesions was also performed. Factors influencing culture outcome of indirectly inoculated corneal samples were identified by a multivariate regression model incorporating quantitative data from sequencing.

RESULTS

Among the 94 included patients with microbial keratitis, contact lens wear (n = 69; 73%) was the most common risk factor. Contact lens wearers displayed significant differences in the bacterial community composition of the corneal lesion compared to no lens wearers, with higher abundance of Staphylococcus spp., Corynebacterium spp., and Stenotrophomonas maltophilia. Targeted sequencing detected a potential corneal pathogen in the highest proportional abundance among 9 of the 24 (38%) culture-negative patients with microbial keratitis. Age, bacterial density in the sample, and prior antibiotic treatment significantly influenced culture outcome of indirectly inoculated corneal samples.

CONCLUSION

Targeted sequencing may provide insights on pathogens in both culture negative episodes of microbial keratitis and among subgroups of patients with microbial keratitis as well as factors influencing culture outcome of indirectly inoculated corneal samples.

Unveiling the ocular battlefield: Insights into Pseudomonas aeruginosa virulence factors and their implications for multidrug resistance

The research investigates the virulence factors of Pseudomonas aeruginosa (P. aeruginosa), a pathogen known for its ability to cause human infections by releasing various exoenzymes and virulence factors. Particularly relevant in ocular infections, where tissue degeneration can occur, even after bacterial growth has ceased due to the potential role of secreted proteins/enzymes. Clinical isolates of P. aeruginosa, both ocular (146) and non-ocular (54), were examined to determine the frequency and mechanism of virulence factors. Phenotypic characterization revealed the production of alginate, biofilm, phospholipase C, and alkaline protease, while genotypic testing using internal uniplex PCR identified the presence of Exo U, S, T, Y, and LasB genes. Results showed a significant prevalence of Exo U and Y genes in ocular isolates, a finding unique to Indian studies. Additionally, the study noted that ocular isolates often contained all four secretomes, suggesting a potential link between these factors and ocular infections. These findings contribute to understanding the pathogenesis of P. aeruginosa infections, particularly in ocular contexts, and highlights the importance of comprehensive virulence factor analysis in clinical settings.

Prognostic indicators of corneal ulcer clinical outcomes at a tertiary care center in the Bronx, New York

PURPOSE

Corneal ulcers frequently result in ocular morbidity and may lead to permanent visual impairment if severe or untreated. This study aims to evaluate the association of patient factors and ocular exam findings on clinical outcomes for patients diagnosed with a corneal ulcer at a tertiary care center in the Bronx, New York.

METHODS

A retrospective chart review was conducted on all ambulatory and admitted patients diagnosed with a corneal ulcer (identified using ICD-10 code H16.0) at Montefiore Medical Center, Bronx, NY between 2016-2022. Patient demographics, presence of known risk factors, characteristics of subsequent clinical course, and microbiological studies were noted. Clinical outcomes following treatment were longitudinally evaluated and categorized based upon the following criteria: 1) 'No Surgical Intervention': No severe complications or surgery required after presentation, 2) 'Surgical Intervention': Decline in BCVA with surgery required for a severe complication.

RESULTS

The search criteria identified 205 patients (205 eyes) with the diagnosis of a corneal ulcer. Mean age was 55.3 ± 21.1 years (mean ± SD). Mean ulcer area at presentation was 7 ± 10.5 mm2. Mean LogMAR at presentation was 1.2 ± 1, and following treatment, improved to 1.0 ± 1. 'Surgical Intervention' outcome was associated with advanced age (p = 0.005), presence of ocular surface disease (p = 0.008), central location of ulcer (p = 0.014), greater ulcer area at presentation (p = 0.003), worse visual acuity at presentation (p < 0.001), and isolation of fungi (p = 0.004).

CONCLUSION

Identification of risk factors associated with a poor clinical prognosis can guide treatment and inform expectations for patients diagnosed with a corneal ulcer. Our study highlights the importance of timely diagnosis, work-up, and initiation of appropriate management, particularly in vulnerable populations where access to specialty care is logistically challenging.

Tetraspanin CD9-derived peptides inhibit Pseudomonas aeruginosa corneal infection and aid in wound healing of corneal epithelial cells

Pseudomonas aeruginosa is a leading cause of corneal infection both within India and globally, often causing a loss of vision. Increasing antimicrobial resistance among the bacteria is making its treatment more difficult. Preventing initial bacterial adherence to the host membrane has been explored here to reduce infection of the cornea. Synthetic peptides derived from human tetraspanin CD9 have been shown to reduce infection in corneal cells both in vitro, ex vivo and in vivo. We found constitutive expression of CD9 in immortalized human corneal epithelial cells by flow cytometry and immunocytochemistry. The synthetic peptides derived from CD9 significantly reduced bacterial adherence to cultured corneal epithelial cells and ex vivo human cadaveric corneas as determined by colony forming units. The peptides also significantly reduced bacterial burden in a murine model of Pseudomonas keratitis and lowered the cellular infiltration in the corneal stroma. Additionally, the peptides aided corneal wound healing in uninfected C57BL/6 mice compared to control mice. These potential therapeutics had no effect on cell viability or proliferation of corneal epithelial cells and have the potential to be developed as an alternative therapeutic intervention.

The activity of antimicrobial peptoids against multidrug-resistant ocular pathogens

BACKGROUND

Ocular infections caused by antibiotic-resistant pathogens can result in partial or complete vision loss. The development of pan-resistant microbial strains poses a significant challenge for clinicians as there are limited antimicrobial options available. Synthetic peptoids, which are sequence-specific oligo-N-substituted glycines, offer potential as alternative antimicrobial agents to target multidrug-resistant bacteria.

METHODS

The antimicrobial activity of synthesised peptoids against multidrug-resistant (MDR) ocular pathogens was evaluated using the microbroth dilution method. Hemolytic propensity was assessed using mammalian erythrocytes. Peptoids were also incubated with proteolytic enzymes, after which their minimum inhibitory activity against bacteria was re-evaluated.

RESULTS

Several alkylated and brominated peptoids showed good inhibitory activity against multidrug-resistant Pseudomonas aeruginosa strains at concentrations of ≤15 μg mL-1 (≤12 µM). Similarly, most brominated compounds inhibited the growth of methicillin-resistant Staphylococcus aureus at 1.9 to 15 μg mL-1 (12 µM). The N-terminally alkylated peptoids caused less toxicity to erythrocytes. The peptoid denoted as TM5 had a high therapeutic index, being non-toxic to either erythrocytes or corneal epithelial cells, even at 15 to 22 times its MIC. Additionally, the peptoids were resistant to protease activity.

CONCLUSIONS

Peptoids studied here demonstrated potent activity against various multidrug-resistant ocular pathogens. Their properties make them promising candidates for controlling vision-related morbidity associated with eye infections by antibiotic-resistant strains.

Applications of photodynamic therapy in keratitis

Keratitis is corneal inflammatory disease which may be caused by several reason such as an injury, allergy, as well as a microbial infection. Besides these, overexposure to ultraviolet light and unhygienic practice of contact lenses are also associated with keratitis. Based on the cause of keratitis, different lines of treatments are recommended. Photodynamic therapy is a promising approach that utilizes light activated compounds to instigate either killing or healing mechanism to treat various diseases including both communicable and non-communicable diseases. This review focuses on clinically-important patent applications and the recent literature for the use of photodynamic therapy against keratitis.

Acute keratoconjunctivitis associated with tisotumab vedotin-tftv for metastatic cervical cancer

Purpose

Tisotumab vedotin-tftv, an antibody-drug conjugate, was recently FDA-approved for metastatic or treatment-resistant cervical cancer. A high rate of ocular comorbidities was seen in pivotal clinical trials. We present a case of a 46-year-old woman who experienced prolonged ocular surface adverse effects associated with use of the drug.

Observations

Our patient was initiated on tri-weekly 2mg/kg infusions of tisotumab for metastatic cervical cancer. Baseline ophthalmic exam was unremarkable. One week after the second infusion, she developed bilateral eyelid edema and chalazia managed with initiation of lid hygiene measures. Preceding the fourth infusion, she developed unilateral pseudomembranous conjunctivitis and bilateral meibomitis that improved with topical corticosteroids. The fifth infusion was subsequently given at a reduced dosage. Despite this, she experienced decreased vision, bilateral diffuse punctate epitheliopathy, and subepithelial haze. The patient was subsequently referred to the cornea service. Symptomatic and clinical improvement was initially achieved with the addition of bandage contact lenses (BCLs). As the keratitis improved, topical steroids were tapered and BCLs removed. She is currently maintained on a regimen that includes eyelid hygiene, preservative-free artificial tears, punctal plugs, autologous serum tears, and lifitegrast. Given the severity of the ophthalmic adverse effects, however, further tisotumab infusions were held.

Conclusions and importance

This is a report of a patient with prolonged ocular surface disease following the initiation of tisotumab, significant enough to lead to discontinuation. Antibody-drug conjugates are an emerging class of therapeutics across oncology, and ophthalmologists should be aware of their potential effects on ocular health.

Dematiaceous fungal keratitis caused by Cladophialophora boppii - A case report

Purpose

To report a rare case of dematiaceous fungal keratitis caused by Cladophialophora boppii (C. boppii) in an immunocompromised patient.

Observations

An 83-year-old male with chronic renal failure was referred to the Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan due to persistent corneal epithelial defects (PEDs) in his left eye. Initial examination revealed decreased central corneal sensitivity and decreased tear secretion in that eye, both thought to be associated with herpetic keratitis. Permanent punctal-plug surgery combined with therapeutic soft contact lens wear was performed to treat the PED, which initially healed, yet recurred. Follow-up examination revealed a 1.0-mm-diameter black lesion consistent with the PED site, which subsequently increased in size, so treatment with miconazole solution eye drops, natamycin ophthalmic ointment, and systemic itraconazole was initially performed. Since the region of the lesion had progressed to corneal perforation, corneal transplantation surgery under general anesthesia was scheduled, yet the patient refused to undergo surgery. Mycological testing via DNA sequencing of the internal transcribed spacer of ribosomal DNA regions revealed that the isolate or pathogen was C. boppii. Mycotic keratitis caused by C. boppii was found to be resistant to antifungal drugs.

Conclusion and importance

This is a rare case of fungal keratitis caused by C. boppii in an elderly immunocompromised patient.

Krupple-like factor 4 (KLF4) methylation signature in host cell in active viral keratitis with epithelial manifestation

HSV1 presents as epithelial or stromal keratitis or keratouveitis and can lead to sight-threatening complications. KLF4, a critical transcription factor, and regulator of cell growth and differentiation, is essential in corneal epithelium stratification and homeostasis. Here, we want to understand the epigenetic modification specifically the methylation status of KLF4 in epithelium samples of HSV1 keratitis patients. After obtaining consent, epithelial scrapes were collected from 7 patients with clinically diagnosed HSV1 keratitis and 7 control samples (patients undergoing photorefractive keratectomy). Genomic DNA was isolated from the collected samples using the Qiagen DNeasy Kit. Subsequently, bisulfite modification was performed. The bisulphite-modified DNA was then subjected to PCR amplification using specific primers designed to target the KLF4, ACTB gene region, allowing for the amplification of methylated and unmethylated DNA sequences. The amplified DNA products were separated and visualized on a 3% agarose gel. KLF4 hypermethylation was found in 6 out of 7 (85.71%) eyes with viral keratitis, while 1 eye showed hypomethylation compared to PRK samples. Out of these 6, there were 2 each of epithelial dendritic keratitis, epithelial geographical keratitis, and neurotrophic keratitis. The patient with hypomethylated KLF4 had a recurrent case of HSV1 keratitis with multiple dendrites and associated vesicular lesions of the lip along with a history of fever. KLF4 hypermethylation in most viral keratitis cases indicated the under functioning of KLF4 and could indicate a potential association between KLF4 hypermethylation and the development or progression of HSV1 keratitis.

Polyhexanide based contact lens storage fluids frequently exhibit insufficient antifungal activity against Fusarium species

PURPOSE

Fusarium keratitis is a severe infection of the anterior eye, frequently leading to keratoplasty or surgical removal of the affected eye. A major risk factor for infection is the use of contact lenses. Inadequate hygiene precautions and mold-growth permissive storage fluids are important risk factors for fungal keratitis. The aim of this study was to comparatively analyze contact lens storage fluids disinfection efficacy against Fusarium species.

METHODS

Eleven commercially available storage fluids were tested. The storage fluids were classified according to their active ingredients myristamidopropyldimethylamine (Aldox), polyhexanide and hydrogen peroxide. Efficacy was tested against isolates belonging to the Fusarium solani and Fusarium oxysporum species complexes as the most common agents of mould keratitis. Tests were carried out based on DIN EN ISO 14729.

RESULTS

All Aldox and hydrogen peroxide (H2O2) based fluids were effective against Fusarium spp., while the majority of polyhexanide based storage fluids showed only limited or no antifungal effects. Efficacy of polyhexanide could be restored by the addition of the pH-regulating agent tromethamine - an additive component in one commercially available product.

CONCLUSIONS

In summary, the use of Aldox- or hydrogen peroxide-based storage fluids may reduce the risk of Fusarium keratitis, while polyhexanide-based agents largely lack efficacy against Fusarium.

Fungal keratitis after amniotic membrane placement

Purpose

We present two cases of fungal keratitis following amniotic membrane transplantation, including Sistotrema biggsiae and Fusarium keratitis.

Observations

A 76-year-old female with a history of anterior basement membrane dystrophy referred for reduced vision and left eye pain ten days following AMT at an outside facility. Despite topical management, the patient continued to worsen clinically, with a recalcitrant course of Fusarium keratitis requiring conjunctival flap, cryotherapy, and intracameral and intrastromal injection. The second case involved a 46-year-old male with a history of recurrent corneal erosions referred for blurry vision and pain in his left eye seven days following AMT. He was found to have Sistotrema biggsiae keratitis and had remarkable visual improvement with topical management.

Conclusions

Fungal keratitis following amniotic membrane placement has not been reported presenting within ten days after transplantation. This is the first report of Sistotrema biggsiae infection in humans. This case series highlights the risk of severe recalcitrant microbial keratitis presenting within days after AMT placement and recognizing fungal etiologies not previously reported in literature. The risk of keratitis following AMT should be considered with close patient follow up, especially in patients with monocular vision.

Impact of removing soft contact lenses 1 day versus 1 month before surgery on the outcomes of microkeratome laser in situ keratomileusis

PURPOSE

To compare the outcomes, safety, efficacy, and predictability of microkeratome laser in situ keratomileusis (LASIK) 24 h and one month or more after removing soft contact lenses.

SETTING

ULTRALASIK Eye Center, Dubai, United Arab Emirates.

METHODS

The patients were divided based on the time of discontinuation of the soft contact lenses before LASIK (Group 1 at 24 h and Group 2 at one month or longer), and the two groups were well matched. Schirmer's testing, tear break-up time, corrected distance visual acuity, uncorrected distance visual acuity, manifest refraction spherical equivalent, and infection rate were evaluated preoperatively and at one week, one month, and six months after treatment.

RESULTS

Group 1 (G1) comprised 1025 eyes, and group 2 (G2) had 1052 eyes. The groups were comparable preoperatively. The overall-mentioned outcomes were comparable between groups with uncorrected distance visual acuity of - 0.084 ± 0.12 logMAR in G1 and - 0.078 ± 0.17 logMAR in the G2 at 6 months (P = 0.322). Tear break-up time as well as Schirmer's testing results was also comparable with no evidence of increased risk of dry eyes or non-inflammatory complications in any of the groups on follow-up visits at 1 week (P = 0.421), 1 month (P = 0.101), and 6 months (P = 0.399) postoperatively. Finally, no infectious complications were recorded in either of the groups.

CONCLUSION

With the absence of corneal warpage, no statistical or clinical difference in microkeratome LASIK outcomes and safety was spotted between the groups despite the difference in SCL discontinuation time before the procedure.

Achromobacter xylosoxidans keratitis in a LASIK flap treated with intrastromal antibiotics: a case report

Intrastromal antibiotic injections are a type of treatment that can be very useful in bacterial keratitis refractory to topical antibiotics. We present the case of a 44-year-old woman with an infiltrate in a laser in situ keratomiuleusis (LASIK) flap and growth of Achromobacter xylosoxidans, who was treated with topical ceftazidime for 1 month. However, after discontinuation of the antibiotic, there was a worsening with growth of the same germ. Topical treatment was reintroduced and, due to suspicion of germ reservoir, it was decided to give three cycles of intrastromal ceftazidime injections, the last one also with moxifloxacin, with good results. After 4 months asymptomatic and without treatment at the moment, no signs of recurrence have been observed. This case supports the usefulness of intraestromal injections in refractory cases to the topical medication.

Preliminary observations on tear film interferometry performed in horses

This retrospective study evaluated tear film (TF) interferometry on horses examined in Northern Italy in 2019-2021. The objectives were to evaluate horses affected by keratitis, and to describe TF values in horses with no evidence of ocular disease. All horses received a complete ophthalmic examination and were examined with the Ocular Surface Analyser, Veterinary-setting, prior to eye manipulation, staining and sample collection. Eighteen horses with no evidence of ocular disease were included in the comparison group. Additionally, 46 horses displaying signs of keratitis (neovascularization, corneal opacities, ulceration, epithelial and subepithelial infiltrates) were evaluated. These horses were divided into presumed non-infectious and infectious or presumed infectious keratitis groups (one with proven bacterial origin, and the others with diagnosed or presumptive keratomycosis) with the former including immune-mediated keratitis. From the observations of TF interferometry in the comparison population the authors concluded that for non-invasive break-up time (NIBUT), the estimated preliminary reference interval was 10.4-31.2s, and for tear meniscus height (TMH), it was 0.215-0.457mm. Moreover, within the keratitis population, from an interferometric point of view punctate lesions of the ocular surface were present in all cases of active diagnosed or presumptive subepithelial keratomycosis but not in any of the non-infectious cases, either non-ulcerative or ulcerative. Limitations of the study include a relatively low number of horses examined and the fact that the diagnosis of infectious keratitis was presumptive and based on clinical improvement after treatment in some cases. To the authors' knowledge, this is the first report of TF interferometry performed in horses.

Patch endothelial keratoplasty for corneal perforations secondary to ocular surface disease: case series

BACKGROUND

Corneal perforation is an ophthalmic emergency. The conventional management of corneal perforation can be associated with severe complications especially in patients with ocular surface disease. Endothelial keratoplasty has been suggested as an alternative surgical technique for the management of corneal perforations. We present a case series of nine patients with corneal perforation and ocular surface disease managed with secondary patch endothelial keratoplasty.

METHODS

This is a retrospective case series of nine patch endothelial keratoplasties performed between 2016 and 2022 at a quaternary eye hospital in Australia. The surgical technique is similar to conventional endothelial keratoplasty except descemetorhexis was not performed.

RESULTS

A total of 9 cases were treated during the review period. Eight of the nine cases had an improvement in visual acuity. One case failed to achieve corneal tectonic objective.

CONCLUSION

Patch endothelial keratoplasty is a safe secondary procedure for the management of corneal perforations in patients with ocular surface disease.

Corneal Deposits: A Presentation of Arthrobacter Keratitis

Introduction

Infectious keratitis, an inflammatory condition of the cornea, poses a significant public health concern globally. Bacterial keratitis, the most common type, primarily involves Staphylococcus aureus and Pseudomonas aeruginosa. Timely diagnosis and treatment are crucial to prevent vision loss.

Case Presentation

This case report presents a 78-year-old male patient with a burning sensation persisting for 1 week. The patient was diagnosed with keratitis caused by Arthrobacter, a Gram-positive coccobacillus commonly found in the environment. While the literature reports a few cases of Arthrobacter species keratitis, limited data exist regarding its clinical course and outcomes. Treatment with ciprofloxacin eye drops resulted in complete resolution of symptoms and a clear cornea upon final follow-up.

Conclusion

Arthrobacter, a rare causative agent of keratitis, requires early suspicion for accurate diagnosis and treatment. Despite the limited literature on Arthrobacter keratitis, this case highlights the importance of considering uncommon pathogens in corneal infections. Further research is necessary to understand the prevalence and clinical course of Arthrobacter keratitis.

Ocular involvement secondary to Monkeypox virus infection

We present the case of a 37-year-old male patient with symptoms compatible with adenoviral conjunctivitis of 5 days' evolution. Topical corticosteroids, lubricants and removal of pseudomembranes were prescribed. PCR analysis of conjunctival exudate was positive for Monkeypox virus. During follow-up, the patient developed corneal ulcers with a torpid course, requiring admission for treatment with Tecovirimat. Ocular involvement by Monkeypox virus is usually mild and self-limiting. Cases with severe visual involvement have been described when there is corneal damage, as exemplified in this case. After admission to hospital for systemic treatment, the patient progressed favourably.

Staphylococcus aureus-derived virulent phenol-soluble modulin α triggers alarmin release to drive IL-36-dependent corneal inflammation

Methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with keratitis produces substantial amounts of phenol-soluble modulin α (PSMα). However, the role of PSMα in S. aureus keratitis remains unclear. We observed that PSMα-producing and PSMα-deficient strains could infect the cornea in our experimental mouse keratitis model; however, only the PSMα-producing strain delayed epithelial wound healing and induced stromal inflammation. PSMα induced damage to the epithelium, the release of alarmins IL-1α and IL-36α, and the expression of inflammatory chemokines by resident corneal cells in the mouse corneal organ culture. The IL-36 (but not IL-1) receptor antagonist attenuated mouse keratitis induced by PSMα-containing bacterial culture supernatants, as well as by infection with PSMα-producing S. aureus, suggesting that the corneal inflammations were dependent on IL-36. Recombinant PSMα elicited IL-36-dependent corneal inflammation in mice. Thus, PSMα and the subsequently released IL-36 are critical factors triggering inflammation during S. aureus keratitis.

Corneal ring infiltrate- far more than Acanthamoeba keratitis: review of pathophysiology, morphology, differential diagnosis and management

OBJECTIVE

Ring infiltrates usually accompany numerous infectious and sterile ocular disorders. Nevertheless, systemic conditions, drugs toxicity and contact lens wear may present with corneal ring infiltrate in substantial part. Considering its detrimental effect on vision, detailed knowledge on etiology, pathophysiology, differential diagnosis, and management should be considered essential for every ophthalmologist.

METHODS

The PUBMED database was searched for "corneal ring infiltrate" and "ring infiltrate" phrases, "sterile corneal infiltrate" and "corneal infiltrate". We analyzed articles written in English on risk factors, pathophysiology, clinical manifestation, morphological features, ancillary tests (anterior-segment optical coherence tomography, corneal scraping, in vivo confocal microscopy), differential diagnosis and management of corneal ring infiltrate.

RESULTS

Available literature depicts multifactorial origin of corneal ring infiltrate. Dual immunological pathophysiology, involving both antibodies-dependent and -independent complement activation, is underlined. Furthermore, we found that the worldwide most prevalent among non-infectious and infectious ring infiltrates are ring infiltrates related to contact-lens wear and bacterial keratitis respectively. Despite low incidence of Acanthamoeba keratitis, it manifests with corneal ring infiltrate with the highest proportion of the affected patients (one third). However, similar ring infiltrate might appear as a first sign of general diseases manifestation and require targeted treatment. Every corneal ring infiltrate with compromised epithelium should be scraped and treat as an infectious infiltrate until not proven otherwise. Of note, microbiological ulcer might also lead to immunological ring and therefore require anti-inflammatory treatment.

CONCLUSION

Corneal ring infiltrate might be triggered not only by ocular infectious and non-infectious factors, but also by systemic conditions. Clinical assessment is crucial for empirical diagnosis. Furthermore, treatment is targeted towards the underlying condition but should begin with anti-infectious regimen until not proven otherwise.

Cell death of Acanthamoeba castellanii following exposure to antimicrobial agents commonly included in contact lens disinfecting solutions

Several antimicrobial agents are commonly included in contact lens disinfectant solutions including chlorhexidine diacetate (CHX), polyhexamethylene biguanide (PHMB) or myristamidopropyl dimethylamine (MAPD); however, their mode of action, i.e. necrosis versus apoptosis is incompletely understood. Here, we determined whether a mechanism of cell death resembling that of apoptosis was present in Acanthamoeba castellanii of the T4 genotype (NEFF) following exposure to the aforementioned antimicrobials using the anticoagulant annexin V that undergoes rapid high affinity binding to phosphatidylserine in the presence of calcium, making it a sensitive probe for phosphatidylserine exposure. The results revealed that under the conditions employed in this study, an apoptotic pathway of cell death in this organism at the tested conditions does not occur. Our findings suggest that necrosis is the likely mode of action; however, future mechanistic studies should be accomplished in additional experimental conditions to further comprehend the molecular mechanisms of cell death in Acanthamoeba.

Case report: Concomitant use of nightly vitamin A ointment with daily PROSE wear for ocular surface disease associated with chronic Stevens-Johnson syndrome

Purpose

To describe a case of chronic ocular surface disease associated with Stevens-Johnson Syndrome (SJS) in which the addition of nightly topical ophthalmic preservative free vitamin A ointment to the daily use of a customized ocular surface prosthetic device (PROSE) appears to mitigate disease progression.

Observations

A 51-year-old female with SJS secondary to lamotrigine use presented for follow up evaluation. Ocular history was significant for acute SJS twenty-four years prior with chronic ocular surface sequelae predominantly affecting the left eye. The condition had been stabilized without progression by utilizing long term PROSE daytime wear along with nightly application of topical ophthalmic vitamin A ointment. The patient reported non-compliance with vitamin A ointment use for the prior three months. The ocular surface examination of the left eye was notable for significantly progressed inferior keratinization and neovascularization which had been unchanged over the course of the three prior annual exams. After restarting nightly topical ophthalmic vitamin A ointment and continuing regular PROSE use, there was no further ocular surface disease progression in the ensuing 4 years of follow up.

Conclusion and Importance

The use of nightly topical ophthalmic vitamin A ointment may be a viable adjuvant therapy alongside daily PROSE use for progressive chronic SJS ocular surface disease.

Successful treatment of an extensively drug-resistant pseudomonal ulcer associated with contaminated artificial tears

PURPOSE

To report a case of bacterial keratitis caused by an extensively drug-resistant (XDR) Pseudomonas aeruginosa strain linked to contaminated artificial tears in the United States. The ulcer was successfully treated without perforation or extracorneal spread.

OBSERVATIONS

An 81-year-old patient presented with a corneal ulcer of the right eye. The patient had a notable complex ocular history including glaucoma and corneal edema from corneal decompensation after prolonged retained lens fragment. Despite starting hourly fortified tobramycin and vancomycin eye drops, the infiltrate grew significantly by the next day. Bacterial culture grew Pseudomonas aeruginosa that was resistant to all tested antibiotics except for intermediate susceptibility to colistin and susceptibility to cefiderocol. Tobramycin-soaked collagen shields were applied daily for three days, and the patient was started on fortified colistin eye drops. The ulcer improved and, after seven weeks of therapy, the infiltrate resolved and resulted in a large central corneal scar.

CONCLUSIONS AND IMPORTANCE

A combination of fortified colistin and tobramycin (administered via a combination of fortified eye drops and tobramycin-soaked collagen shields) appears to be an effective treatment option for extensively drug-resistant Pseudomonas aeruginosa corneal ulcers.

The gene expression and proteomic profiling of Acanthamoeba isolates

INTRODUCTION

The free-living protozoan Acanthamoeba can cause severe keratitis known as Acanthamoeba Keratitis (AK) and granulomatous amoebic encephalitis (GAE). The pathogenesis of Acanthamoeba includes intricate interactions between the organism and the host's immune system. The downstream analysis of a well-annotated genome assembly along with proteomic analysis can unravel several biological processes and aid in the identification of potential genes involved in pathogenicity.

METHODS

Based on the next-generation sequencing data analysis, genes including lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein were selected as probable pathogenic targets that were validated by conventional PCR in a total of 30 Acanthamoeba isolates. This was followed by real-time PCR for the evaluation of relative gene expression in the keratitis and amoebic encephalitis animal model induced using keratitis (CHA5), encephalitis (CHA24) and non-pathogenic environmental isolate (CHA36). In addition, liquid chromatography-mass spectrometry (LC-MS/MS) was performed for keratitis, encephalitis, and non-pathogenic environmental isolate before and after treatment with polyhexamethylene biguanide (PHMB).

RESULTS

The conventional PCR demonstrated the successful amplification of lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein genes in clinical and environmental isolates. The expression analysis revealed phospholipase, lysophospholipase, and mannose-binding genes to be significantly upregulated in the keratitis isolate (CHA 5) during AK in the animal model. In the case of the amoebic encephalitis model, phospholipase, lysophospholipase, S8/S53 peptidase, and carboxylesterase were significantly upregulated in the encephalitis isolate compared to the keratitis isolate. The proteomic data revealed differential protein expression in pathogenic versus non-pathogenic isolates in the pre and post-treatment with PHMB.

CONCLUSION

The gene expression data suggests that lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein (MBP) could play a role in the contact-dependent and independent mechanisms of Acanthamoeba pathogenesis. In addition, the proteomic profiling of the 3 isolates revealed differential protein expression crucial for parasite growth, survival, and virulence. Our results provide baseline data for selecting possible pathogenic targets that could be utilized for designing knockout experiments in the future.

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.

Innovative cold atmospheric plasma (iCAP) decreases corneal ulcer formation and bacterial loads and improves anterior chamber health in methicillin resistant Staphylococcus aureus keratitis

Bacterial keratitis is a vision-threatening infection of the cornea that is typically treated with antibiotics. However, antibiotics sometimes fail to eradicate the infection and do not prevent or repair the damage caused directly by the bacteria or the host immune response to the infection. Our group previously demonstrated that treatment of Pseudomonas aeruginosa keratitis in rabbits with innovative cold atmospheric plasma (iCAP) resulted in reduced edema, ulcer formation, and bacterial load. In this study, we investigated the efficacy of iCAP treatment in methicillin-resistant Staphylococcus aureus (MRSA). New Zealand white rabbits were infected intrastromally with MRSA then treated with iCAP, moxifloxacin, vancomycin, or combination of iCAP with each antibiotic to assess the safety and efficacy of iCAP treatment compared to untreated controls and antibiotics. iCAP treatment significantly reduced bacterial loads and inflammation, improved anterior chamber clarity, and prevented corneal ulceration compared to untreated controls and antibiotic treatment. Safety assessments of grimace test scores and tear production showed that iCAP was not significantly different from either antibiotic treatment in terms of distress or tear production. Combination iCAP/antibiotic treatment did not appear to provide significant added benefit over iCAP alone. Our findings suggest that the addition of iCAP may be a viable tool in reducing damage to the cornea and anterior chamber of the eye following S. aureus keratitis.

Corynebacterium oculi-related bacterium may act as a pathogen and carrier of antimicrobial resistance genes in dogs: a case report

BACKGROUND

The genus Corynebacterium comprises well-known animal and human pathogens as well as commensals of skin and mucous membranes. Species formerly regarded as contaminants are increasingly being recognized as opportunistic pathogens. Corynebacterium oculi has recently been described as a human ocular pathogen but has so far not been reported in dogs.

CASE PRESENTATION

Here we present two cases of infection with a novel Corynebacterium sp., a corneal ulcer and a case of bacteriuria. The two bacterial isolates could not be identified by MALDI-TOF MS. While 16 S rRNA gene (99.3% similarity) and rpoB (96.6% identity) sequencing led to the preliminary identification of the isolates as Corynebacterium (C.) oculi, whole genome sequencing revealed the strains to be closely related to, but in a separate cluster from C. oculi. Antimicrobial susceptibility testing showed high minimal inhibitory concentrations of lincosamides, macrolides, tetracycline, and fluoroquinolones for one of the isolates, which also contained an erm(X) and tet-carrying plasmid as well as a nonsynonymous mutation leading to an S84I substitution in the quinolone resistance determining region of GyrA.

CONCLUSIONS

While the clinical signs of both dogs were alleviated by antimicrobial treatment, the clinical significance of these isolates remains to be proven. However, considering its close relation with C. oculi, a known pathogen in humans, pathogenic potential of this species is not unlikely. Furthermore, these bacteria may act as reservoir for antimicrobial resistance genes also in a One Health context since one strain carried a multidrug resistance plasmid related to pNG3 of C. diphtheriae.

Photoactivated chromophore-corneal cross-linking accelerates corneal healing in fungal keratitis: an updated meta-analysis

AIM

To determine the effectiveness and safety of photoactivated chromophore-corneal cross-linking (PACK-CXL) adjuvant in infectious keratitis by April 5, 2022.

METHODS

We searched randomized controlled trials (RCTs) comparing standard antibiotic treatment (SAT) plus PACK-CXL to SAT in infectious keratitis in Embase, MEDLINE with PubMed, Web of Science, and Cochrane Library. We independently screened and extracted data using predesigned tables. Cochrane's risk-of-bias tool was utilized to examine the quality of RCTs. A random-effects model was employed to determine the overall effect size of the meta-analyses. Grading of Recommendations, and Assessment, Development and Evaluations (GRADE) was also performed to examine the quality of evidence.

RESULTS

Seven eligible RCTs with 283 patients were acquired. Adjuvant PACK-CXL reduced the time needed to perform corneal healing in fungal keratitis (- 1.33 months; 95% CI, - 1.83 to - 0.42, I2 = 0%, P < 0.05) as compared to SAT alone. The risks of adverse events were not significantly different both in fungal and bacterial keratitis. Due to the substantial heterogeneity among studies, such as population, the type and severity of infectious keratitis, drug regimens of SAT, PACK-CXL protocol, and the judgment of subjective outcomes, the evidence grade was low.

CONCLUSION

Adjuvant PACK-CXL accelerates fungal keratitis healing as compared to SAT alone. But more rigorous RCTs are required to determine the clinical effectiveness and safety.

In praise of povidone-iodine application in ophthalmology

Polyvinyl pyrrolidone or povidone-iodine (PVP-I) is a water-soluble complex formed by the combination of iodine and a water-soluble polymer, polyvinyl pyrrolidone. This complex exerts bactericidal, fungicidal, and virucidal action by gradually releasing free iodine at the site of application to react with pathogens. In ophthalmology, PVP-I is used as a disinfectant and antiseptic agent for preoperative preparation of the skin and mucous membranes and for treating contaminated wounds. PVP-I has been shown to reduce effectively the risk of endophthalmitis in various ocular procedures, including cataract surgery and intravitreal injections; however, it has also been used in the treatment of conjunctivitis, keratitis, and endophthalmitis, with promising results especially in low-resource situations. PVP-I has been associated with complications such as postoperative eye pain, persistent corneal epithelial defects, ocular inflammation, and an attendant risk of keratitis. In cases of poor PVP-I tolerance, applying PVP-I at lower concentrations or using alternative antiseptics such as chlorhexidine should be considered. We provide an update on the efficacy of PVP-I in the prophylaxis and treatment of conjunctivitis, keratitis, and endophthalmitis and a comprehensive analysis of the current literature regarding the use of PVP-I in the management of these ocular conditions. Also, PVP-I-related adverse effects and toxicities and its alternatives are discussed. The goal is to present a thorough evaluation of the available evidence and to offer practical recommendations for clinicians regarding the therapeutic usage of PVP-I in ophthalmology.

Quercetin protects against Aspergillus fumigatus keratitis by reducing fungal load and inhibiting TLR-4 induced inflammatory response

PURPOSE

To investigate the antifungal and anti-inflammatory effects of quercetin in Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Draize eye test was performed in mice to evaluate the toxicity of quercetin, and the antifungal effects on A. fumigatus were assessed via scanning electron microscopy (SEM), propidium iodide uptake, and adherence assay. In fungal keratitis (FK) mouse models, immunostaining was performed for investigating toll-like receptor 4 (TLR-4) expression and macrophage infiltration. Real-time PCR, ELISA, and Western blot were used to evaluate the expression of pro-inflammatory factors IL-1β, TNF-α, and IL-6 in infected RAW264.7 cells. Cells were also treated with TLR-4 siRNA or agonist CRX-527 to investigate mechanisms underlying the anti-inflammatory activity of quercetin.

RESULTS

Quercetin at 32 μM was non-toxic to corneal epithelial and significantly inhibited A. fumigatus growth and adhesion, and also altered the structure and reduced the number of mycelia. Quercetin significantly reduced macrophage infiltration in the mouse cornea, and attenuated the expression of TLR-4 in the corneal epithelium and stroma of mice with keratitis caused by A. fumigatus. In RAW264.7 cells infected by A. fumigatus, quercetin downregulated TLR-4 along with pro-inflammatory factors IL-1β, TNF-α, and IL-6. RAW cells with TLR-4 knockdown had reduced expression of factors after A. fumigatus infection, which was decreased even further with quercetin treatment. In contrast, cells with CRX-527 had elevated inflammatory factors compared to control, which was significantly attenuated in the presence of quercetin.

CONCLUSION

Quercetin plays a protective role in mouse A. fumigatus keratitis by inhibiting fungal load, disrupting hyphae structure, macrophage infiltration, and suppressing inflammation response in macrophages via TLR-4 mediated signaling pathway.

Late-onset distal-apical intracorneal ring-segments keratopathy: an analysis of a large sample in a multicenter study

PURPOSE

To review the prevalence and describe the characteristics, of cases with late-onset intracorneal ring segments (ICRS) keratopathy in a multicenter study.

METHODS

A retrospective multicentric case-series study was performed in a specialized keratoconus service, from Buenos Aires, Argentina. An electronic clinical chart from patients with ICRS keratopathy between January 1999 and January 2019 was reviewed. We included cases with late-onset distal-apical ICRS keratopathy, which was defined as a persistent corneal lesion developed 12 months or later after implantation, located over, around, or closer to the ICRS. All the surgeries were performed by a manual corneal tunnel creation technique. Samples were taken to rule out infectious etiology.

RESULTS

From 5217 eyes that underwent ICRS implantation, 13 cases (0.24%) were detected. The keratopathy onset was 72 ± 42.98 months (29-133) after ICRS implantation. Cultures were negative in all cases. An ICRS exchange was made for five cases in stage I and four in stage II. Four cases presented with partial ICRS extrusion in stage III. ICRS exchange was possible in two of them and a penetration keratoplasty was necessary for the rest. All cases remained stable 1 year after surgical procedures.

CONCLUSIONS

A late-onset distal-apical ICRS keratopathy was detected with low prevalence (0.24%) in a large sample. It was classified into three stages according to its severity. Different treatments were selected for each stage, obtaining stable results 1 year after treatment.

Emerging Roles of cGAS-STING Signaling in Mediating Ocular Inflammation

Cyclic GMP-AMP (cGAMP) synthase (cGAS), a sensor of cytosolic DNA, recognizes cytoplasmic nucleic acids to activate the innate immune responses via generation of the second messenger cGAMP and subsequent activation of the stimulator of interferon genes (STINGs). The cGAS-STING signaling has multiple immunologic and physiological functions in all human vital organs. It mediates protective innate immune defense against DNA-containing pathogen infection, confers intrinsic antitumor immunity via detecting tumor-derived DNA, and gives rise to autoimmune and inflammatory diseases upon aberrant activation by cytosolic leakage of self-genomic and mitochondrial DNA. Disruptions in these functions are associated with the pathophysiology of various immunologic and neurodegenerative diseases. Recent evidence indicates important roles of the cGAS-STING signaling in mediating inflammatory responses in ocular inflammatory and inflammation-associated diseases, such as keratitis, diabetic retinopathy, age-related macular degeneration, and uveitis. In this review, we summarize the recently emerging evidence of cGAS-STING signaling in mediating ocular inflammatory responses and affecting pathogenesis of these complex eye diseases. We attempt to provide insightful perspectives on future directions of investigating cGAS-STING signaling in ocular inflammation. Understanding how cGAS-STING signaling is modulated to mediate ocular inflammatory responses would allow future development of novel therapeutic strategies to treat ocular inflammation and autoimmunity.

Severe KIDAR syndrome caused by deletion in the AP1B1 gene: Report of a teenage patient and systematic review of the literature

Autosomal recessive keratitis-ichthyosis-deafness syndrome (KIDAR MIM #242150) is a very rare disorder caused by pathogenic loss-of-function variants in the AP1B1 gene. So far, nine patients have been reported in the literature and more clinical descriptions are essential to further delineate the phenotype of KIDAR. Here we report a new patient with KIDAR and compare the clinical findings with those from the other published cases with molecular confirmation. We describe a 14-year-old male born to non-consanguineous parents with unremarkable family history. The patient had fetal ascites, neonatal pancreatic insufficiency with consequent failure to thrive, feeding difficulties, recurrent infections and sepsis. The skin examination was remarkable for an ichthyosis with conspicuous palmoplantar keratoderma, sparse and brittle hair with alopecia on the vertex and slight bilateral ectropion. He had short stature, thin build, frontal bossing, small teeth and prominent abdomen. Additional features were congenital profound bilateral sensorineural deafness, photosensitivity and photophobia. Mild global developmental delay was noted. Persistent mild anemia, neutropenia, thrombocytopenia, and low serum copper, ceruloplasmin and growth hormone were also present. Brain magnetic resonance imaging (MRI) showed cerebral atrophy and thin corpus callosum. Genetic testing revealed a homozygous deletion in the AP1B1 gene, possibly including the same exons as a previously reported deletion. Comparing the phenotypes of all reported individuals, they are highly concordant and major features are enteropathy with feeding difficulties, failure to thrive, ichthyosis, palmoplantar keratoderma, sensorineural deafness and sparse and brittle hair. Here we report other features present in more than one patient that could be part of the phenotypic spectrum and suggest copy number variation analysis to be performed alongside sequencing of the AP1B1 gene in case of suspicion.

Microbiological spectrum and antibiotic susceptibility patterns of non-viral conjunctivitis over 16 years at a tertiary eye care center in Southern India

PURPOSE

To determine the trends in the microbial spectrum and antibacterial susceptibility patterns of non-viral conjunctivitis over 16 years.

METHODS

Microbiology data were reviewed from 2006-2021 for all the patients with clinically and culture-proven infectious conjunctivitis. Conjunctival swabs and/or conjunctival scrapings were collected for microbiological workup, and the demographic and antibiotic susceptibility data were extracted from the EMR (Electronic Medical Record). For statistical analysis, χ2-test was performed.

RESULTS

Of the 1711 patients, 814 (47.57%) were culture positive and 897 (52.43%) were culture negative. Of the total culture-proven conjunctivitis cases, 775/814 (95.20%) were bacteria, and 39/814 (4.80%) were fungi. Among these bacterial isolates, 75.74% were gram-positive bacteria, while 24.26% were gram negative. The predominant gram-positive pathogens isolated were S. epidermidis (16.7%), S. aureus (17.9%) (p < 0.05), and S. pneumoniae (18.2%), while Haemophilus spp. (36.2%) (p < 0.05) was the most often isolated gram-negative bacteria (36.2%), and Aspergillus spp. was the most commonly isolated fungus (50%). The susceptibility of gram-positive bacteria to cefazoline increased from 90.46 to 98% (p = 0.01), whereas the susceptibility for gatifloxacin decreased in both gram-positive (81-41%; p < 0.0001) and gram-negative bacteria (73-58%; p = 0.02).

CONCLUSIONS

Increasing resistance of ocular isolates to mainstay antibiotics is a concern, and this data can assist healthcare practitioners in making informed choices regarding the treatment of ocular infections with ophthalmic antibiotics.

Post-laser refractive surgery keratitis: A concise narrative review

Laser refractive surgery (LRS) is a specialized surgical discipline within ophthalmology that focuses on vision correction via laser techniques. LRS requires a high rate of accuracy and exactitude to improve the visual outcome and minimize complications, which may lead to delayed visual recovery. Keratitis, either infectious or noninfectious, is a post-LRS complication that requires early diagnosis and proper interventional measures. In this narrative review, we summarize different aspects of keratitis following LRS. This literature review aims to provide a thorough understanding of the causes of post-LRS infectious keratitis and its appropriate management for successful outcomes.

3-month post-procedural evaluation of a combined intense pulsed light and photo-biomodulation system in the treatment of meibomian gland dysfunction

PURPOSE

Meibomian gland dysfunction (MGD) is the leading cause of dry eye syndrome. It is a frequent and underdiagnosed condition with a significant socioeconomic impact. We propose here the evaluation of a platform combining intense pulsed light and photo-biomodulation in the treatment of Meibomian gland dysfunction.

METHODS

We conducted a retrospective study at Brest University Hospital analyzing a cohort of 74 eyes (37 patients) at 1 month and 3 months after a protocol of 3 Eye-Light® (Espansione Group, Italy) sessions 14 days apart between January 2019 and April 2020. The primary outcome was the change in OSDI quality of life score. Secondary outcomes were the SPEED questionnaire score; tear break-up time (BUT), Oxford score, non-invasive break-up time (NIBUT), lipid layer thickness, lacrimal meniscus height and Meibomian gland atrophy rate. Tolerance of the treatment was also evaluated.

RESULTS

We found a significant improvement in OSDI scores at 1 month (-17.32; 95% CI (-25.84; -8.79), P<0.0001) and 3 months (-16.95; 95% CI (-25.26; -8.64), P<0.0001). The SPEED score, BUT, Oxford score, Meibomian gland atrophy and NIBUT were also statistically significantly improved. Tolerance to treatment was very good despite two cases of herpetic keratitis, which resolved on treatment.

CONCLUSION

Treatment with the Eye-Light® in three sessions every two weeks significantly reduced symptoms and ocular surface damage in patients with MGD. This data suggests that the use of Eye-Light® may represent a good option for patients with MGD.

Successful treatment of multidrug-resistant Pseudomonas aeruginosa keratitis with meropenem eye drops - a case report

BACKGROUND

This case report describes the course and therapeutic management of a fast-spreading bacterial keratitis caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa).

CASE PRESENTATION

A 27-year-old male contact lens wearer presented with a multi-resistant, fast spreading P. aeruginosa keratitis. After initial resistance to various antibiotic therapies, testing revealed a MDR P. aeruginosa. The keratitis was treated successfully with specially prepared 50 mg/ml off-label meropenem eye drops for 18 days as well as systemic meropenem for seven days with rapid improvement of the corneal infiltrate.

CONCLUSION

This case report demonstrates the combination of topical and systemic meropenem as a useful treatment option for corneal ulcers caused by MDR P. aeruginosa.

The role of matrix metalloproteinases in infectious corneal ulcers

During infectious keratitis, the production of collagenolytic and inflammatory substances, along with increased corneal matrix metalloproteinase (MMP) activity, induces the degradation of corneal collagen and may cause postkeratitis complications, such as opacity, thinning, and corneal perforation. MMPs, especially MMP-2 and MMP-9, are overexpressed in infectious keratitis and sustained over time by inflammatory and nonmicrobial mechanisms. The high MMP levels are correlated with excessive corneal destruction in bacterial, herpetic, fungal, and acanthamoeba infections. Nonspecific treatments, such as tetracyclines, particularly doxycycline, or corticosteroids, are used as adjuvants to antimicrobials to alleviate the disproportionate degradation and inflammation of the corneal layers caused by corneal MMPs and decrease the recruitment and infiltration of inflammatory cells. Treatments showing inhibition of specific MMPs (Galardin, ZHAWOC7726), interfering with pro-MMP activation (EDTA, ascorbic acid), or showing anticytokine effect (epigallocatechin-2-gallate, TRAM-34) have been reported. Other treatments show a direct action over corneal collagen structure such as corneal cross-linking or have been associated with reduction of MMP levels such as amniotic membrane grafting. Although the use of these drugs has been shown in studies to be effective in controlling inflammation, especially in experimental ones, robust studies are still needed based on randomized and randomized clinical trials to demonstrate their potential effect as adjuvants in the management of infectious keratitis.

Bacterial keratitis in a tertiary hospital in São Paulo: a 21-year review of the epidemiological, laboratory, and clinical data

Infectious keratitis is a sight-threatening condition that is usually an ocular emergency. The visual outcome depends on prompt and accurate clinical management as well as geographic and epidemiological awareness. We conducted a retrospective observational study to define the epidemiological and laboratory profile, as well as the clinical course of bacterial keratitis in a tertiary hospital in São Paulo over 21 years. Information about age, sex, predisposing factors, topical and surgical treatment, visual acuity, ulcers' classification, bacterioscopy, culture, and antibiotic sensitivity tests were collected. This study included 160 patients. The mean age was 65.1 ± 18.4 years and risk factors were identified in 83.1 % of the patients. Empirical topical fortified cephalosporin with an aminoglycoside or fourth-generation fluoroquinolone was curative for 66.2 % of the cases. The mean treatment duration was 22.5 ± 9 days. The mean variation of visual acuity was -0.25 logMAR, p < 0.001. Culture revealed 64 % of Gram-positive bacteria. All Gram-positive bacteria were sensitive to cephalothin, vancomycin, and quinolones. All Gram-negative bacteria were sensitive to gentamicin, tobramycin, amikacin, and ciprofloxacin. These findings reinforce the importance of prompt empirical treatment of severe corneal ulcers with a fortified cephalosporin and aminoglycoside or a fourth-generation fluoroquinolone as there are equally effective. Collected data was insufficient to evaluate resistance of ocular infections over time in this population.

Pediatric herpes zoster ophthalmicus: a systematic review

PURPOSE

While typically affecting older adults and immunocompromised individuals, herpes zoster ophthalmicus (HZO) has been reported with varying manifestations and complications in children. In this review, we evaluate reported cases of pediatric HZO in the literature and discuss the epidemiology, risk factors, clinical presentation, treatment and outcomes.

METHODS

A literature search on PubMed, Scopus, and Web of Science databases was performed using the terms "pediatric herpes zoster ophthalmicus" and "herpes zoster ophthalmicus children." Publications that were not specific to HZO or pediatric populations were excluded, as were publications that were not available to review or not published in the English language.

RESULTS

Fifty-seven reports describing 130 cases of HZO or HZO-related complications were reviewed. Major risk factors for pediatric HZO included intrauterine exposure to varicella or primary varicella infection at a young age; HZO also occurred in patients who had received varicella vaccination. Both healthy and immunocompromised children were affected, with the majority of affected children being immunocompetent. The diagnosis of HZO is primarily clinical. Children appear to have good vision recovery and resolution of symptoms if they are treated promptly and if they adhere to treatment regimens, except for irreversible vision loss related to uncommon complications such as optic neuritis.

CONCLUSION

HZO occurs in both healthy and immunocompromised children. Recognizing this treatable condition is essential for reducing ocular and systemic morbidity. Long-term follow-up and assessments of the impact on health in adulthood are lacking. More systematic study is needed to determine the incidence of HZO in children and appropriate diagnostic and treatment protocols for the care of pediatric patients with HZO.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Therapeutic contact lens-related infection by a novel pathogenic fungus Coniochaeta hoffmannii-a case report

This study aims to report a rare instance of corneal decompensation brought on by Coniochaeta hoffmannii fungus invasion of a bandage contact lens (BCL). A 71-year-old man with pseudophakic bullous keratopathy (PBK) had BCL treatment for four months to symptomatically reduce pain and itching in his right eye. However, the patient unexpectedly lost his vision. The slit-lamp examination revealed an edematous cornea; the extensive direct inspection raised suspicion of BCL. For morphological characterization, the BCL extracted was inoculated onto 5% sheep blood agar and PDA. By Sanger sequencing method the isolate's genomic DNA was molecularly identified as C. hoffmannii.

Keratouveitis and conjunctivitis caused by Euphorbia ingens: A case review

Euphorbia ingens is a ubiquitous plant who has a milky sap. It can accidentally harm human´s eye by its caustic nature, causing conjunctivitis, keratitis, uveitis, anterior staphyloma and corneal scarring in untreated patients. We present the case of a patient whose eye came into contact with the milky sap. He suffered conjunctivitis, corneal epithelial defect and uveitis. After intensive treatment, his eye made a complete recovery. We recommend gloves and protecting glasses before handling these types of plants.

Candida species causing fungal keratitis: molecular identification, antifungal susceptibility, biofilm formation, and clinical aspects

The study aimed to evaluate the clinical aspects, molecular identification, biofilm formation, and antifungal susceptibility profile of Candida species isolated from fungal keratitis. Thirteen Candida isolates from 13 patients diagnosed with Candida keratitis were retrieved and grown in pure culture. Species identification was performed by micromorphology analysis and ITS-rDNA sequencing. The broth microdilution method tested the minimum inhibitory concentration (MIC) of four antifungal drugs (fluconazole, amphotericin B, voriconazole, and anidulafungin). The biofilms were cultured and incubated with antifungal drugs for 24 h. The XTT reduction assay measured the biofilm activity. Biofilm MICs were calculated based on a 50% reduction in metabolic activity compared with the activity of the drug-free control. Among isolates, two were C. albicans, 10 were C. parapsilosis (sensu stricto), and one was C. orthopsilosis. All isolates were classified as susceptible or intermediate to all four antifungal drugs. Four isolates were very low biofilm producers (30%). Nine isolates were biofilm producers, and all biofilm samples were unsusceptible to all drugs tested. Previous ocular surgery was the most common underlying condition for fungal keratitis (84.6%), and C. parapsilosis was the most frequent Candida species (76.9%). Four patients (30.7%) needed keratoplasty, whereas two (15.3%) required evisceration. The biofilm formation ability of Candida isolates decreased antifungal susceptibility compared with planktonic cells. Despite in vitro antifungal susceptibility, almost half of the patients were unresponsive to clinical treatment and needed surgery.

Eye fungal infections: a mini review

Ocular fungal infections annually affect more than one million individuals worldwide. The management of these infections is problematic, mainly due to the limited availability of effective antifungal agents. Thus, ocular infections are increasingly recognized as important causes of morbidity and blindness, especially keratitis and endophthalmitis. Thus, this review aims to demonstrate the importance of fungal eye infections through the description of the main related aspects, with emphasis on the treatment of these infections. For this purpose, a search for scientific articles was conducted in databases, such as Medline, published from 2000 onwards, addressing important aspects involving fungal eye infections. In addition, this work highlighted the limited therapeutic arsenal available and the severity associated with these infections. Thus, highlighting the importance of constantly updating knowledge about these pathologies, as it contributes to agility in choosing the available and most appropriate therapeutic alternatives, aiming at positive and minimally harmful results for that particular patient.

Diagnostic performance of deep learning in infectious keratitis: a systematic review and meta-analysis protocol

INTRODUCTION

Infectious keratitis (IK) represents the fifth-leading cause of blindness worldwide. A delay in diagnosis is often a major factor in progression to irreversible visual impairment and/or blindness from IK. The diagnostic challenge is further compounded by low microbiological culture yield, long turnaround time, poorly differentiated clinical features and polymicrobial infections. In recent years, deep learning (DL), a subfield of artificial intelligence, has rapidly emerged as a promising tool in assisting automated medical diagnosis, clinical triage and decision-making, and improving workflow efficiency in healthcare services. Recent studies have demonstrated the potential of using DL in assisting the diagnosis of IK, though the accuracy remains to be elucidated. This systematic review and meta-analysis aims to critically examine and compare the performance of various DL models with clinical experts and/or microbiological results (the current 'gold standard') in diagnosing IK, with an aim to inform practice on the clinical applicability and deployment of DL-assisted diagnostic models.

METHODS AND ANALYSIS

This review will consider studies that included application of any DL models to diagnose patients with suspected IK, encompassing bacterial, fungal, protozoal and/or viral origins. We will search various electronic databases, including EMBASE and MEDLINE, and trial registries. There will be no restriction to the language and publication date. Two independent reviewers will assess the titles, abstracts and full-text articles. Extracted data will include details of each primary studies, including title, year of publication, authors, types of DL models used, populations, sample size, decision threshold and diagnostic performance. We will perform meta-analyses for the included primary studies when there are sufficient similarities in outcome reporting.

ETHICS AND DISSEMINATION

No ethical approval is required for this systematic review. We plan to disseminate our findings via presentation/publication in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022348596.