Infectious keratitis in Vietnam: etiology, organisms, and management at Vietnam National Eye Hospital

AIM: To report the etiologies, risk factors, treatments, and outcomes of infectious keratitis (IK) at a major Vietnamese eye hospital. METHODS: This is a retrospective review of all cases of IK at Vietnam National Eye Hospital (VNEH) in Hanoi, Vietnam. Medical histories, demographics, clinical features, microbiological results, and treatment outcomes were reviewed. RESULTS: IK was diagnosed in 1974 eyes of 1952 patients, with ocular trauma being the greatest risk factor for IK (34.2%), frequently resulting from an agriculture-related injury (53.3%). The mean duration between symptom onset and presentation to VNEH was 19.3±14.4d, and 98.7% of patients had been treated with topical antibiotic and/or antifungal agents prior to evaluation at VNEH. Based on smear results of 1706 samples, the most common organisms identified were bacteria (n=1107, 64.9%) and fungi (n=1092, 64.0%), with identification of both bacteria and fungi in 614 (36.0%) eyes. Fifty-five of 374 bacterial cultures (14.7%) and 426 of 838 fungal cultures (50.8%) were positive, with the most commonly cultured pathogens being Pseudomonas aeruginosa, Streptococcus pneumonia, Fusarium spp., and Aspergillus spp. Corneal perforation and descemetocele developed in 391 (19.8%) and 93 (4.7%) eyes, respectively. Medical treatment was successful in resolving IK in 50.4% eyes, while 337 (17.1%) eyes underwent penetrating or anterior lamellar keratoplasty. Evisceration was performed in 7.1% of eyes, most commonly in the setting of fungal keratitis. CONCLUSION: Ocular trauma is a major risk factor for IK in Vietnam, which is diagnosed in almost 400 patients each year at VNEH. Given this, and as approximately one quarter of the eyes that develop IK require corneal transplantation or evisceration, greater emphasis should be placed on the development of prevention and treatment programs for IK in Vietnam.

PACK-CXL vs. antimicrobial therapy for bacterial, fungal, and mixed infectious keratitis: a prospective randomized phase 3 trial

Background Infectious keratitis is a major cause of global blindness. We tested whether standalone photoactivated chromophore corneal cross-linking (PACK-CXL) may be an effective first-line treatment in early to moderate infectious keratitis, compared with standard antimicrobial treatment. Methods This is a randomized, controlled, multinational phase 3 clinical trial. Participants in five centers in Egypt, India, Iran, Israel, and China, aged ≥ 18 years, with infectious keratitis of presumed bacterial, fungal, or mixed origin, were randomly assigned (1:1) to PACK-CXL, or antimicrobial therapy. Outcomes measures included healing, defined as time to re-epithelialization of the corneal epithelial defect in the absence of inflammatory activity in the anterior chamber and clearance of stromal infiltrates. Treatment success was defined as the complete resolution of signs of infection. Results Between July 21, 2016, and March 4, 2020, participants were randomly assigned to receive PACK-CXL (n = 18) or antimicrobial therapy per American Academy of Ophthalmology (AAO) guidelines (n = 21). No participants were lost to follow-up. Four eyes were excluded from the epithelialization time analysis due to treatment failure: two in the antimicrobial therapy group, and two in the PACK-CXL group. Success rates were 88.9% (16/18 patients) in the PACK-CXL group and 90.5% (19/21 patients) in the medication group. There was no significant difference in time to complete corneal re-epithelialization (P = 0.828) between both treatment groups. Conclusions PACK-CXL may be an alternative to antimicrobial drugs for first-line and standalone treatment of early to moderate infectious keratitis of bacterial or fungal origin. Trial registration This trial is registered at ClinicalTrials.gov, trial registration number: NCT02717871

Infectious Keratitis Associated with Contact Lenses

The use of contact lenses for correcting refraction, suppressing myopia progression, and cosmetic purposes is increasing steadily. Contact lenses have various effects on the corneal surface and corneal infection can occur following obstruction of tear flow, micro-damage to corneal epithelial cells, corneal hypoxia, changes in corneal immunity, and exposure to contaminants. When a patient who used to wear contact lenses presents with keratitis, it is important to distinguish whether it is an infection; if it is an infection, it is important to find the causative strain and promptly treat it appropriately. Since improper lens care is related to infection, appropriate patient education is necessary, and the risk of contact lens infection should be reduced through regular ophthalmic examinations.

Infectious Keratitis: An Update on Role of Epigenetics

Epigenetic mechanisms modulate gene expression and function without altering the base sequence of DNA. These reversible, heritable, and environment-influenced mechanisms generate various cell types during development and orchestrate the cellular responses to external stimuli by regulating the expression of genome. Also, the epigenetic modifications influence common pathological and physiological responses including inflammation, ischemia, neoplasia, aging and neurodegeneration etc. In recent past, the field of epigenetics has gained momentum and become an increasingly important area of biomedical research As far as eye is concerned, epigenetic mechanisms may play an important role in many complex diseases such as corneal dystrophy, cataract, glaucoma, diabetic retinopathy, ocular neoplasia, uveitis, and age-related macular degeneration. Focusing on the epigenetic mechanisms in ocular diseases may provide new understanding and insights into the pathogenesis of complex eye diseases and thus can aid in the development of novel treatments for these diseases. In the present review, we summarize the clinical perspective of infectious keratitis, role of epigenetics in infectious keratitis, therapeutic potential of epigenetic modifiers and the future perspective.

Post penetrating keratoplasty infectious keratitis: Clinico-microbiological profile and predictors of outcome

Purpose To study the clinico-microbiological profile, outcomes and prognostic factors of post penetrating keratoplasty (PKP) infectious keratitis. Methods Retrospective review of medical records of 78 patients with post PKP infectious keratitis presenting between January 2014 and December 2018. Demographic, clinical and microbiological profile was documented and predictors of treatment and graft success were evaluated using univariate and subsequent multivariate logistic regression analysis. Results Mean age of patients was 52.17 ± 15.51 years and mean infiltrate size was 19.39 ± 19.68 mm2. Mean duration of presentation with infection post PKP was 11.66 ± 10.65 months. Culture positivity was seen in 64 eyes (82.05%). Bacterial growth was observed in 47 eyes (60.25%), fungal growth in 17 (21.79%) and no microbiological growth in 14 eyes (17.94%). At 3 months the visual acuity (VA) improved in 37 eyes (47.44%), did not change in 27 (34.62%) and deteriorated in 14 (17.95%). Graft failure was noted in 53 eyes (73.08%). Surgical intervention was needed in 47 (60.25%) eyes of which most common was therapeutic PKP in 32 eyes (41.02%). Treatment failure was noted with fungal infection ( p = 0.05), poorer vision at presentation ( p = 0.02), larger infiltrate area ( p = 0.002) and graft infection developing before 1 year ( p = 0.02). Graft failure was noted with associated endophthalmitis ( p = 0.02), poorer VA at presentation ( p = 0.01) and larger infiltrate area ( p = 0.02). Conclusion Post PKP infectious keratitis is a sight threatening ocular condition. It is associated with high incidence of graft failure and frequently requires surgical intervention. Fungal etiology, larger infiltrate size, poorer vision at presentation and associated endophthalmitis carries a poorer prognosis.

Fusarium Keratitis—Review of Current Treatment Possibilities

In many parts of the world, fungi are the predominant cause of infectious keratitis; among which, Fusarium is the most commonly isolated pathogen. The clinical management of this ophthalmic emergency is challenging. Due to the retardation of the first symptoms from an injury and the inability to differentiate fungal from bacterial infections based on clinical symptoms and difficult microbial diagnostics, proper treatment, in many cases, is postponed. Moreover, therapeutical options of Fusarium keratitis remain limited. This paper summarizes the available treatment modalities of Fusarium keratitis, including antifungals and their routes of administration, antiseptics, and surgical interventions.

Determination of probability of causative pathogen in infectious keratitis using deep learning algorithm of slit-lamp images

Corneal opacities are important causes of blindness, and their major etiology is infectious keratitis. Slit-lamp examinations are commonly used to determine the causative pathogen; however, their diagnostic accuracy is low even for experienced ophthalmologists. To characterize the “face” of an infected cornea, we have adapted a deep learning architecture used for facial recognition and applied it to determine a probability score for a specific pathogen causing keratitis. To record the diverse features and mitigate the uncertainty, batches of probability scores of 4 serial images taken from many angles or fluorescence staining were learned for score and decision level fusion using a gradient boosting decision tree. A total of 4306 slit-lamp images including 312 images obtained by internet publications on keratitis by bacteria, fungi, acanthamoeba, and herpes simplex virus (HSV) were studied. The created algorithm had a high overall accuracy of diagnosis, e.g., the accuracy/area under the curve for acanthamoeba was 97.9%/0.995, bacteria was 90.7%/0.963, fungi was 95.0%/0.975, and HSV was 92.3%/0.946, by group K-fold validation, and it was robust to even the low resolution web images. We suggest that our hybrid deep learning-based algorithm be used as a simple and accurate method for computer-assisted diagnosis of infectious keratitis.

Population-based study on the prevalence, clinical characteristics and vision-related quality of life in patients with corneal opacity resulting from infectious keratitis: results from the Corneal Opacity Rural Epidemiological study

AimTo estimate prevalence and characterise clinical features and vision-related quality of life (VR-QoL) of corneal opacities (COs) resulting from infectious keratitis in a rural North Indian population.MethodsThe Corneal Opacity Rural Epidemiological study was a cross-sectional study conducted in 25 randomly selected clusters of rural Gurgaon, Haryana, India to determine prevalence of corneal disease across all age groups. During house-to-house visits, sociodemographic details, presence, type and clinical characteristics of corneal disease, laterality and resultant visual impairment (VI) was noted. Subgroup analysis of data was performed to understand the prevalence, clinical characteristics, VR-QoL in patients with CO due to infectious keratitis. VR-QoL scores were compared with healthy controls.ResultsOverall, 65 of 12 113 participants had evidence of infectious keratitis-related CO with a mean age of 63.3 (±14.7 SD) years. Prevalence of infectious keratitis-related CO, including both bilateral (12/65) and unilateral (53/65) cases was 0.54% (95% CI 0.41 to 0.66) seen in a total of 77 eyes of 65 participants. Mean visual acuity was 1.18±0.80 with 30/77 (38.9%) eyes having a presenting visual acuity <3/60. Most of the CO due to infectious keratitis was <3 mm in size (61.03%; 47/77), nebular (42.85%; 33/77) and central (49.35%; 38/77) in location. These participants had significantly higher VR-QoL scores and hence poorer VR-QoL across all three domains of vision function (scores of 28 vs 22, 7.5 vs 5 and 15.5 vs 9, respectively; p<0.0001) when compared with healthy controls.ConclusionThe data from this study give an insight into the burden and clinical characteristics of COs resulting from infectious keratitis. VR-QoL is significantly impaired in patients with CO resulting from infectious keratitis, both in bilateral and unilateral cases.