Risk factors for low vision related functioning in the Mycotic Ulcer Treatment Trial: a randomised trial comparing natamycin with voriconazole

Urgent unmet needs in the care of bacterial keratitis: An evidence-based synthesis

Bacterial corneal infections, or bacterial keratitis (BK), are ophthalmic emergencies that frequently lead to irreversible visual impairment. Though increasingly recognized as a major cause of global blindness, modern paradigms of evidence-based care in BK have remained at a diagnostic and therapeutic impasse for over half a century. Current standards of management - based on the collection of corneal cultures and the application of broad-spectrum topical antibiotics - are beset by important yet widely underrecognized limitations, including approximately 30% of all patients who will develop moderate to severe vision loss in the affected eye. Though recent advances have involved a more clearly defined role for adjunctive topical corticosteroids, and novel therapies such as corneal crosslinking, overall progress to improve patient and population-based outcomes remains incommensurate to the chronic morbidity caused by this disease. Recognizing that the care of BK is guided by the clinical axiom, "time equals vision", this chapter offers an evidence-based synthesis for the clinical management of these infections, underscoring critical unmet needs in disease prevention, diagnosis, and treatment.

Thymol Protects against Aspergillus Fumigatus Keratitis by Inhibiting the LOX-1/IL-1β Signaling Pathway

OBJECTIVE

To explore the anti-inflammatory effects and mechanisms of action of thymol in Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

The minimum inhibitory concentration of thymol against A. fumigatus was detected. To characterize the anti-inflammatory effects of thymol, mouse corneas and human corneal epithelial cells were pretreated with thymol or dimethyl sulfoxide (DMSO) before infection with A. fumigatus spores. Slit-lamp microscopy, immunohistochemistry, myeloperoxidase detection, quantitative real-time polymerase chain reaction, and Western blotting were used to assess infection. Neutrophil and macrophage recruitment, in addition to the secretion of LOX-1 and IL-1β, were quantified to evaluate the relative contribution of thymol to the inflammatory response.

RESULTS

We confirmed that the growth of A. fumigatus was directly inhibited by thymol. In contrast with the DMSO group, there was a lower degree of inflammation in the mouse corneas of the thymol-pretreated group. This was characterized by significantly lower clinical scores, less inflammatory cell infiltration, and lower expression of LOX-1 and IL-1β. Similarly, in vitro experiments indicated that the production of LOX-1 and IL-1β was significantly inhibited after thymol treatment, in contrast with the DMSO-pretreated group.

CONCLUSION

Our findings demonstrate that thymol exerted a direct fungistatic activity on A. fumigatus. Furthermore, thymol played a protective role in fungal keratitis by inhibiting LOX-1/IL-1β signaling pathway and reducing the recruitment of neutrophils and macrophages.

Foundational concepts in the biology of bacterial keratitis

Bacterial infections of the cornea, or bacterial keratitis (BK), are notorious for causing rapidly fulminant disease and permanent vision loss, even among treated patients. In the last sixty years, dramatic upward trajectories in the frequency of BK have been observed internationally, driven in large part by the commercialization of hydrogel contact lenses in the late 1960s. Despite this worsening burden of disease, current evidence-based therapies for BK - including broad-spectrum topical antibiotics and, if indicated, topical corticosteroids - fail to salvage vision in a substantial proportion of affected patients. Amid growing concerns of rapidly diminishing antibiotic utility, there has been renewed interest in urgently needed novel treatments that may improve clinical outcomes on an individual and public health level. Bridging the translational gap in the care of BK requires the identification of new therapeutic targets and rational treatment design, but neither of these aims can be achieved without understanding the complex biological processes that determine how bacterial corneal infections arise, progress, and resolve. In this chapter, we synthesize the current wealth of human and animal experimental data that now inform our understanding of basic BK pathophysiology, in context with modern concepts in ocular immunology and microbiology. By identifying the key molecular determinants of clinical disease, we explore how novel treatments can be developed and translated into routine patient care.

Fungal keratitis: Pathogenesis, diagnosis and prevention

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

Early deep anterior lamellar keratoplasty for fungal keratitis poorly responsive to medical treatment

PurposeTo investigate the efficacy of early therapeutic deep anterior lamellar keratoplasty (DALK) in eradicating fungal keratitis that is poorly responsive to medical treatment.Patients and methodsTwenty-three eyes (23 patients) underwent early therapeutic DALK within 15 to 50 days from the onset of symptoms. The adopted eligibility criteria for early DALK included the following: active fungal keratitis affecting the optical zone with ulcer confined in the 6.00 mm central cornea; deeper than 150 μm but not exceeding 300 μm; and poorly responsive to medical treatment.ResultsThe big bubble technique was accomplished in 74% (17) of eyes, whereas manual dissection was performed in the remaining 26% (6) of eyes. Histopathological examination did not show any sign of fungal colonization in the peripheral and deep stromal lamellae in any case. All grafts were transparent postoperatively, and no recurrence of infection occurred. Median best spectacle corrected visual acuity significantly improved from 2.0 (1.0 interquartile range) logMAR to 0.1 (0.1 interquartile range) logMAR (P<0.01). The mean follow-up was 32±10 months. Neither episode of rejection nor graft failure was noted during the follow-up period.ConclusionEarly DALK could represent a safe therapeutic approach to eradicate fungal keratitis that affects the optical zone and is poorly responsive to medical treatment.

Predictors of Corneal Perforation or Need for Therapeutic Keratoplasty in Severe Fungal Keratitis: A Secondary Analysis of the Mycotic Ulcer Treatment Trial II

Importance

Identifying patients with infectious keratitis who are at risk of experiencing a poor outcome may be useful to allocate resources toward high-risk patients, particularly in resource-poor settings.

Objective

To determine baseline patient and ulcer characteristics that predict a high risk of developing corneal perforation and/or the need to undergo therapeutic penetrating keratoplasty (TPK).

Design, Setting, and Participants

This is a secondary analysis of Mycotic Ulcer Treatment Trial II, a multicenter, double-masked, placebo-controlled randomized clinical trial that enrolled 240 patients with smear-positive filamentous fungal corneal ulcers who enrolled between May 2010 and August 2015. Participants had a baseline visual acuity of 20/400 or worse and were randomized to receive oral voriconazole or a placebo (all participants received topical voriconazole, 1%). After 39 participants (16.3%) were enrolled, topical natamycin, 5%, was also added.

Main Outcomes and Measures

The primary outcome of this secondary analysis was the rate of corneal perforation or the need to undergo TPK.

Results

The mean (SD) age at enrollment was 49 (13) years, 104 participants (43.3%) were women, and all were of Southeast Asian descent. The presence of hypopyon at baseline indicated 2.28 times the odds of the patient developing corneal perforation and/or needing TPK (95% CI, 1.18-4.40; P = .01). Study participants whose infiltrate involved the posterior one-third had a 71.4% risk of developing corneal perforation and/or needing TPK. For each 1-mm increase in the geometric mean of the infiltrate, there was 1.37 (95% CI, 1.12-1.67; P = .002) increased odds of developing perforation and/or needing TPK. Other clinical features such as visual acuity, baseline culture positivity, type of filamentous fungal organism and duration of symptoms, and demographic characteristics, such as sex and occupation, were not significant predictors in the multivariable regression analysis.

Conclusions and Relevance

These results suggest that risk stratification from baseline ulcer characteristics can identify those at highest risk for developing corneal perforation and/or needing TPK.

Trial Registration

clinicaltrials.gov Identifier: NCT00996736.

Quality-of-Life Outcomes From a Randomized Clinical Trial Comparing Antimetabolites for Intermediate, Posterior, and Panuveitis

PURPOSE

To evaluate the changes in quality of life in noninfectious uveitis patients treated with 2 of the most commonly prescribed antimetabolite treatments.

DESIGN

Secondary analysis of a multicenter, block-randomized clinical trial.

METHODS

Eighty patients at Aravind Eye Hospitals in Madurai and Coimbatore, India, with noninfectious intermediate, posterior, or panuveitis were randomized to receive oral methotrexate, 25 mg weekly, or oral mycophenolate mofetil, 1 g twice daily, and were followed up monthly for 6 months. Best-corrected visual acuity, Indian Vision Function Questionnaire (IND-VFQ), and Medical Outcomes Study 36-item Short Form Survey (SF-36) were obtained at enrollment and at 6 months (or prior, in the event of early treatment failure).

RESULTS

IND-VFQ scores, on average, increased by 9.2 points from trial enrollment to 6 months (95% confidence interval [CI]: 4.9, 13.5, P = .0001). Although the SF-36 physical component summary score did not significantly differ over the course of the trial, the mental component summary score decreased by 2.3 points (95% CI: -4.4, -0.1, P = .04) and the vitality subscale decreased by 3.5 points (95% CI: -5.6, -1.4, P = .001). Quality-of-life scores did not differ between treatment arms. Linear regression modeling showed a 3.2-point improvement in IND-VFQ score for every 5-letter improvement in visual acuity (95% CI: 1.9, 4.3; P < .001).

CONCLUSIONS

Although uveitis treatment was associated with increased vision and vision-related quality of life, patient-reported physical health did not change after 6 months of treatment, and mental health decreased. Despite improved visual outcomes, uveitis patients receiving systemic immunosuppressive therapy may experience a deterioration in mental health-related quality of life.

Review of clinical and basic approaches of fungal keratitis

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