Pivotal Role of Corneal Fibroblasts in Progression to Corneal Ulcer in Bacterial Keratitis

Herpes Simplex Keratitis and Vitamin D Receptor Agonist: Two Case Reports

BACKGROUND

Herpes simplex keratitis (HSK) is a disease characterized by the recurrent infection of the cornea, mainly due to infection caused by herpes simplex virus type 1. The suppression of recurrence can suppress progressive corneal scarring, ulcers, and perforation. Cornea contains vitamin D receptors (VDRs). VDR agonists show antimicrobial activity.

CASE PRESENTATION

In this case report, I describe two female patients aged 76 and 85 years old in whom the administration of a VDR agonist led to the suppression of the recurrence of HSK. The former patient had repeated HSK recurrence for over 10 years after the initial infection. The latter patient developed HSK immediately after vitrectomy, and her cornea remained susceptible to infection, resulting in recurrence. Both patients were trying to suppress recurrence by applying acyclovir ophthalmic ointment, but their medication adherence was declining. So, they switched to oral treatment with 0.5 μg of the VDR agonist per day, and since then, there has been no recurrence of HSK. Oral treatment with the VDR agonist is still ongoing.

CONCLUSIONS

This report highlights the cases where ways were examined to improve medication adherence in elderly patients who had a risk of HSK recurrence. Both patients responded to VDR agonist treatment and were able to suppress recurrence.

The cellular response of lipopolysaccharide-induced inflammation in keratoconus human corneal fibroblasts to RB-PDT: Insights into cytokines, chemokines and related signaling pathways

PURPOSE

Rose Bengal Photodynamic Therapy (RB-PDT) offers dual therapeutic benefits by enhancing corneal stiffness and providing antibacterial activity, presenting significant potential for patients with keratoconus complicated by keratitis. Our purpose was to assess the effect of rose bengal photodynamic therapy (RB-PDT) on the expression of pro-inflammatory cytokines and chemokines, as well as on extracellular matrix (ECM)-related molecules, in lipopolysaccharide (LPS)-induced inflammation of keratoconus human corneal fibroblasts (KC-HCFs). Additionally, the involvement of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways which are downstream of the Toll-like receptor 4 (TLR4) pathway were examined.

METHODS

KC-HCFs were stimulated with varying concentrations of LPS (0-10 μg/ml), which was followed by RB-PDT. The expression levels of interleukin-1β (IL-1β), IL-6, IL-8, interferon alpha 2 (IFNA2), IFNB1, intercellular adhesion molecule 1 (ICAM-1), chemokine (C-C motif) ligand 4 (CCL-4), collagen I, collagen V, lysyl oxidase (LOX), transforming growth factor β 1(TGF-β1) were measured using qPCR, ELISA, or western blot. The activation of the NF-κB and MAPK pathways was assessed using qPCR and western blot.

RESULTS

In LPS-induced inflammation of KC-HCFs, the expression of IL-6 was further amplified by the treatment with RB-PDT (p = 0.001). However, the activation of the MAPK and NF-κB pathways did not increase following RB-PDT. Additionally, RB-PDT reduced the transcription of collagen I and collagen V (p≤0.03), while the transcription of LOX and TGF-β1 secretion remained unchanged in KC-HCFs exposed to LPS.

CONCLUSION

In LPS-induced inflammation of KC-HCFs treated with RB-PDT, despite the increased expression of pro-inflammatory cytokines, the activation of the TLR4 signaling pathways is lacking. RB-PDT may have no adverse effects on corneal scar formation of keratoconus corneas in the short term.

Calcifediol and paricalcitol as adjunctive therapies for HSV-1 keratitis and corneal perforation: A case report

RATIONALE

Herpes simplex virus 1 establishes a latent infection in trigeminal ganglia. Reactivation causes cold sores, as well as viral keratitis. The purpose of this study was to report potential benefits of using active vitamin D receptor ligands (VDR-agonists) as adjunctive therapies for the treatment of infectious corneal perforations, and prevention of HSV recurrence.

PATIENT CONCERNS

A 57-year-old female with a past history of episodic, poorly-healing, corneal erosions, recurring orolabial herpetic lesions, as well as PCR-confirmed recurrences of herpes simplex keratitis presented with a burning sensation and slight pain in the right eye. Examination indicated HSV keratitis. Topical antibiotic and oral antiviral treatments were prescribed. Despite these standard-of-care treatments, a perforated corneal ulcer ensued.

DIAGNOSES

Corneal perforation associated with HSV-1 keratitis recurrence, later confirmed by PCR analysis of corneal scrapings.

INTERVENTIONS

Corneal perforation was treated with a human fibrin glue, fortified with multilayered amniotic membrane transplant, as well as a therapeutical contact lens. Following surgery, calcifediol and paricalcitol were started as oral adjunctive therapies in an attempt to boost tissue regeneration and innate-immunity within the slow-healing cornea. Anterior segment optical-coherence tomography was used to measure corneal thickness. Frequent follow-ups with various specialists allowed for comprehensive patient evaluation, and meticulous screening for any signs indicating potential HSV-1 recurrence.

OUTCOMES

Following calcifediol-paricalcitol therapy corneal thickening, and re-epithelization ensued. During combined calcifediol-paricalcitol therapy, the patient has had no recurrence of herpes simplex keratitis, or orolabial herpes lesions.

LESSONS

Corneal stabilization avoided a high-risk, full-thickness corneal transplantation, facilitating future cataract surgery, and allowing for some degree of visual recovery in this eye.

Sodium butyrate alleviates lipopolysaccharide-induced inflammation through JAK/STAT signalling in primary human corneal fibroblasts

BACKGROUND

Bacterial keratitis is a common cause of blindness. Antibiotic treatment leads to the rapid release of lipopolysaccharide (LPS), which can activate corneal fibroblasts and cause persistent and excessive inflammatory responses. The anti-inflammatory drugs currently used to treat keratitis have serious side effects. Therefore, the ability of sodium butyrate (NaB), which can suppress the production of proinflammatory cytokines and promote the production of anti-inflammatory cytokines, to ameliorate keratitis was assessed in the present study.

METHODS

The effect of NaB on the viability of primary human corneal fibroblasts was assayed with a CCK-8 kit. Cell migration was assessed by an in vitro scratch assay. Cell phenotypes were assessed by Western blotting and immunofluorescence staining. An antibody array was used to measure the production of proinflammatory cytokines and chemokines.

RESULTS

At 0-1 mM, NaB had no significant effect on cell viability, promoted the expression of the keratocyte marker keratocan and inhibited the fibroblast marker vimentin. Inhibition of cell migration was observed in the wound healing assay. By targeting the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway, NaB decreased the levels of inflammation-related cytokines and chemokines whose expression was induced by LPS.

CONCLUSIONS

NaB maintained the keratocyte phenotype, inhibited cell migration, and relieved LPS-induced inflammatory responses through the JAK/STAT signalling pathway.

Novel ophthalmic hyaluronic acid-hydrogel with curcumin nanoparticles for enhanced healing of ulcerative keratitis in rabbit model

Corneal ulcers, whether melting or indolent, are common in humans and companion animals. Treatment involves local administration of antibiotic eye drops and corneal healing drugs. Compared to traditional treatments for ulcerative keratitis, herbal medicines offer unique advantages, such as potent anti-inflammatory effects and inhibition of proinflammatory cytokines. Curcumin, extracted from the Curcuma Longa plant, possesses extensive pharmacological properties, such as anti-inflammatory, anti-cancer, and antioxidant properties, and is used in various medicines. In this study, we developed a novel ophthalmic drop hydrogel using a formulation of Curcumin NPs encapsulated with β-cyclodextrin and hyaluronic acid, to accelerate corneal healing and improve the quality of healed structures. The formation of Curcumin NPs into Hyaluronic acid-based hydrogels was characterized by zeta, FTIR, and scanning electron microscope (SEM) analyses. A total of 25 healthy male New Zealand Albino rabbits were experimentally induced with ulcerative keratitis and treated individually with topical medication. Rabbits were divided into five groups. Fluorescein dye staining, corneal clarity score, Schirmer tear test, proinflammatory cytokine measurement, and pathologic factors assessments were used to evaluate the optimised Curcumin NPs with β-cyclodextrin in Hyaluronic acid hydrogel. Our results demonstrated that the optimized Curcumin NPs with β-cyclodextrin in hyaluronic acid hydrogel significantly reduced the frequency of medication administration compared to conventional therapies, enhancing the quality of healed structures and effectively treating ulcerative keratitis. All findings in this study provide new insight into designing and fabricating novel ophthalmic medicine for ulcerative keratitis for topical usage.

Substance P promotes transforming growth factor-β-induced collagen synthesis in human corneal fibroblasts

Corneal fibroblasts maintain homeostasis of the corneal stroma by mediating the synthesis and degradation of extracellular collagen, and these actions are promoted by transforming growth factor-β (TGF-β) and interleukin-1β (IL-1β), respectively. The cornea is densely innervated with sensory nerve fibers that are not only responsible for sensation but also required for physiological processes such as tear secretion and wound healing. Loss or dysfunction of corneal nerves thus impairs corneal epithelial wound healing and can lead to neurotrophic keratopathy. The sensory neurotransmitter substance P (SP) promotes corneal epithelial wound healing by enhancing the stimulatory effects of growth factors and fibronectin. We have now investigated the role of SP in collagen metabolism mediated by human corneal fibroblasts in culture. Although SP alone had no effect on collagen synthesis or degradation by these cells, it promoted the stimulatory effect of TGF-β on collagen type I synthesis without affecting that of IL-1β on the expression of matrix metalloproteinase-1. This effect of SP on TGF-β-induced collagen synthesis was accompanied by activation of p38 mitogen-activated protein kinase (MAPK) signaling and was attenuated by pharmacological inhibition of p38 or of the neurokinin-1 receptor. Our results thus implicate SP as a modulator of TGF-β-induced collagen type I synthesis by human corneal fibroblasts, and they suggest that loss of this function may contribute to the development of neurotrophic keratopathy.NEW & NOTEWORTHY This study investigates the role of substance P (SP) in collagen metabolism mediated by human corneal fibroblasts in culture. We found that, although SP alone had no effect on collagen synthesis or degradation by corneal fibroblasts, it promoted the stimulatory effect of transforming growth factor-β on collagen type I synthesis without affecting that of interleukin-1β on the expression of matrix metalloproteinase-1.

Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

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.

Structure and properties of the acellular porcine cornea irradiated with electron beam and its in-situ implantation

Different sterilization doses of the electron beam (E-beam) will change the properties of biomaterials and affect their clinical application. Acellular porcine cornea (APC) is a promising corneal substitute to alleviate the shortage of corneal resources. The residual DNA was significantly reduced to 18.50 ± 3.19 ng/mg, and the clearance rate of α-Gal was close to 100% after the treatment with freezing-thawing combined enzyme, indicating that the decellularization was effective. The effects of different E-beam doses at 0, 2, 8, 15, and 25 kGy on the APC were studied. With the increase in irradiation dose, the transmittance, tensile strength, and swelling ratio of APC gradually decreased, but the resistance to enzymatic degradation was stronger than that of non-irradiated APC, especially at 8 kGy. The structure of APC was denser after irradiation, but the dose of 25 kGy could cause partial collagen fiber fracture and increase the pore size. The cell viability of the APC irradiated by 15 and 25 kGy were greater than 80%. After the implantation in rabbit corneas, there was no obvious neovascularization and inflammation, but the dose of 25 kGy had a more destructive effect on the chemical bonds of collagen, which made the APC easier to be degraded. The thickness of APC in the 25 kGy group was thinner than that in the 15 kGy group 1 year after surgery, and the epithelium grew more slowly, so the E-beam dose of 15 kGy might be more suitable for the sterilization of APC.

Glutamine alleviates Lipopolysaccharide-induced corneal epithelial inflammation and oxidative stress in dogs

Pseudomonas aeruginosa is a common pathogenic bacteria in canine ophthalmology. Lipopolysaccharide (LPS), a component in the cell wall of gram-negative bacteria, is released following bacterial lysis and causes pathology and inflammation of the cornea. Antibiotics are used to treat bacterial keratitis, and the reuse of antibiotics can easily cause bacterial resistance. Research has shown that glutamine (GLN) has anti-inflammatory and antioxidant biological functions. Herein, we explored the effects and underlying mechanisms of GLN and established an LPS-induced cornea inflammation model. Treatment groups comprised: control check (CK), LPS, LPS + GLN, and Sham groups. Topical GLN treatment alleviated corneal opacity, reduced corneal injury, and accelerated corneal wound healing. Furthermore, GLN treatment altered the uniform distribution of corneal epithelial cells and transformed the healing approach of these cells in the corneal wound from crawling to filling. The expression of Toll-like receptor 4 (TLR4), IL-6, TNF-α, and p-p65 and the activity of myeloperoxidase and superoxide dismutase decreased while the content of malondialdehyde increased in the LPS + GLN group compared with those in the LPS group. Thus, our study suggests that LPS-induced inflammation and oxidative stress may be suppressed via the TLR4/NF-κB signaling pathway by GLN and that GLN could be used as an adjunct therapy to reduce antibiotic use.

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.

Complement-mediated inflammation and mitochondrial energy metabolism in the proteomic profile of myopic human corneas

Myopia is one of the most common causes of visual impairment worldwide. To identify proteins related to myopiagenesis, data-independent acquisition proteomic analysis was performed using corneal lenticules of myopic patients who underwent small incision lenticule extraction surgery. A total of 19 lenticules from 19 age and sex-matched patients were analyzed, 10 in high refractive error (HR, spherical equivalent over -6.00 D) group and 9 in low refractive error (LR, spherical equivalent between -3.00 and - 1.00 D) group. Differentially expressed proteins (DEPs) were identified by comparing the corneal proteome between the two groups. Functional analyses were performed to explore the biological pathways and interactions of the DEPs. 107 DEPs (67 upregulated and 40 downregulated in HR group, compared to LR) were identified from 2138 quantified proteins. Functional analyses indicated that upregulated proteins were primarily involved in the complement pathways and extracellular matrix (ECM) remodeling, while downregulated proteins were involved in mitochondrial energy metabolism. Western blot analysis confirmed increased complement C3a and apolipoprotein E in HR samples, further supporting the proteomics data. In conclusion, this proteomic study reveals that proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism might be key effectors in myopiagenesis. SIGNIFICANCE: Myopia has become one of the most prevalent causes of visual impairment, especially in Asia. The underlying mechanism of myopia development is still up for debate. This study compares the proteomic profiles of high and low myopic corneas, identifying differentially expressed proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism. The findings of this study could provide novel insights into the pathogenesis of myopia. The complement system and mitochondrial energy metabolism may provide potential therapeutic targets in the treatment and prevention of myopia.

Targeting collagen damage for sustained in situ antimicrobial activities

Antimicrobial peptides (AMPs) are promising anti-infective drugs, but their use is restricted by their short-term retention at the infection site, non-targeted uptake, and adverse effects on normal tissues. Since infection often follows an injury (e.g., in a wound bed), directly immobilizing AMPs to the damaged collagenous matrix of the injured tissues may help overcome these limitations by transforming the extracellular matrix microenvironment of the infection site into a natural reservoir of AMPs for sustained in situ release. Here, we developed and demonstrated an AMP-delivery strategy by conjugating a dimeric construct of AMP Feleucin-K3 (Flc) and a collagen hybridizing peptide (CHP), which enabled selective and prolonged anchoring of the Flc-CHP conjugate to the damaged and denatured collagen in the infected wounds in vitro and in vivo. We found that the dimeric Flc and CHP conjugate design preserved the potent and broad-spectrum antimicrobial activities of Flc while significantly enhancing and extending its antimicrobial efficacy in vivo and facilitating tissue repair in a rat wound healing model. Because collagen damage is ubiquitous in almost all injuries and infections, our strategy of targeting collagen damage may open up new avenues for antimicrobial treatments in a range of infected tissues.

Corticosteroid-Antibiotic Interactions in Bacteria that Cause Corneal Infection

Purpose

Although a comprehensive knowledge of antibiotic/corticosteroid combinations is essential for the appropriate treatment of eye infections, the impact of their co-administration has not been well studied to date. A systematic pharmacodynamic/pharmacokinetic study to determine the effects of cotreatment with various antibiotics and corticosteroids was conducted.

Methods

Four bacterial strains, seven antibiotics, and four corticosteroids were used in the analyses. Drug interactions were evaluated by considering antibacterial effects with a checkerboard assay and intracellular concentrations in human corneal epithelial cells.

Results

The drug combinations that showed the most stable effects against Pseudomonas aeruginosa was levofloxacin-prednisolone. Stable combinations against the three types of Gram-positive bacteria were neomycin-prednisolone, ofloxacin-dexamethasone, ofloxacin-prednisolone, and polymyxin-dexamethasone. The cellular concentrations were changed for the gatifloxacin-fluorometholone, moxifloxacin-fluorometholone, tobramycin-dexamethasone, and tobramycin-prednisolone combinations.

Conclusions

Loteprednol and fluorometholone reduced the antibacterial effects of all of the tested antibiotics in this study. Dexamethasone and prednisolone showed various effects in this regard, depending on the co-administered antibiotic. Prior knowledge of specific antibiotic/corticosteroid interactions provides valuable information to clinical practitioners by combining data on the antibacterial and intracellular uptake effects of their co-administration.

Translational Relevance

When using antibiotics and corticosteroids, drug combinations can be selected by referring to the results of this study.

Urokinase-type plasminogen activator (uPA) negatively regulates α-smooth muscle actin expression via Endo180 and the uPA receptor in corneal fibroblasts

Corneal fibroblasts are embedded within an extracellular matrix composed largely of collagen type 1, proteoglycans, and other proteins in the corneal stroma, and their morphology and function are subject to continuous regulation by collagen. During wound healing and in various pathological conditions, corneal fibroblasts differentiate into myofibroblasts characterized by the expression of α-smooth muscle actin (α-SMA). Endo180, also known as urokinase-type plasminogen activator (uPA) receptor-associated protein (uPARAP), is a collagen receptor. Here we investigated whether targeting of Endo180 and the uPA receptor (uPAR) by uPA might play a role in the regulation of α-SMA expression by culturing corneal fibroblasts derived from uPA-deficient (uPA^-/-) or wild-type (uPA^+/+) mice in a collagen gel or on plastic. The expression of α-SMA was upregulated, the amounts of full-length Endo180 and uPAR were increased, and the levels of both transforming growth factor-b (TGF-β) expression and Smad3 phosphorylation were higher in uPA^-/- corneal fibroblasts compared with uPA^+/+ cells under the collagen gel culture condition. Antibodies to Endo180 inhibited these effects of uPA deficiency on a-SMA and TGF-b expression, whereas a TGF-b signaling inhibitor blocked the effects on Smad3 phosphorylation and a-SMA expression. Our results suggest that uPA deficiency might promote the interaction between collagen and Endo180 and thereby increase a-SMA expression in a manner dependent on TGF-β signaling. Expression of α-SMA is thus negatively regulated by uPA through targeting of Endo180 and uPAR.

Comparison of 16S rDNA Amplicon Sequencing With the Culture Method for Diagnosing Causative Pathogens in Bacterial Corneal Infections

Purpose

The purpose of this study was to explore if 16S rDNA amplicon sequencing can improve the conventional diagnosis of causative pathogens for bacterial corneal infection.

Methods

Corneal scraping and conjunctiva and eyelid margin swab samples from infected eyes of patients diagnosed with "bacterial corneal infection" and conjunctiva and eyelid margin swab samples from a random eye of healthy participants were collected. Each swab was used for both aerobic and anaerobic cultures and 16S rDNA amplicon sequencing. The V3 to V4 region of the 16S rDNA was amplified using polymerase chain reaction (PCR) and sequenced on the Illumina HiSeq 2500 Sequencing Platform.

Results

The overall culture positivity rate for all 72 samples was 69% (72% in the bacterial keratitis group and 67% in the healthy control group), whereas 1719 operational taxonomic units in total were generated using 16S rDNA amplicon sequencing with each sample showing 123 to 337 different genera. Staphylococcus, Corynebacterium, Propionibacterium, and Micrococcus most frequently appeared in culture, whereas Streptococcus, Acinetobacter, and Lactobacillus were the most common genera, with large ratios in 16S rDNA amplicon sequencing. The causative pathogens detected by the two methods were inconsistent for most samples, except for several corneal samples.

Conclusions

We suggest that a combination of different techniques, such as clinical observation, microscopic analysis, culture, and next-generation sequencing techniques including 16S rDNA amplicon sequencing, should be used to comprehensively analyze pathogens in corneal and external ocular infections.

Translational Relevance

This paper uses a basic research methodology for studying the microbiome in ocular samples to help improve the diagnostic accuracy of corneal and external ocular infections.