Risk factors for perforation in microbial corneal ulcers in north India

Cell therapy in the cornea: The emerging role of microenvironment

The cornea is an ideal testing field for cell therapies. Its highly ordered structure, where specific cell populations are sequestered in different layers, together with its accessibility, has allowed the development of the first stem cell-based therapy approved by the European Medicine Agency. Today, different techniques have been proposed for autologous and allogeneic limbal and non-limbal cell transplantation. Cell replacement has also been attempted in cases of endothelial cell decompensation as it occurs in Fuchs dystrophy: injection of cultivated allogeneic endothelial cells is now in advanced phases of clinical development. Recently, stromal substitutes have been developed with excellent integration capability and transparency. Finally, cell-derived products, such as exosomes obtained from different sources, have been investigated for the treatment of severe corneal diseases with encouraging results. Optimization of the success rate of cell therapies obviously requires high-quality cultured cells/products, but the role of the surrounding microenvironment is equally important to allow engraftment of transplanted cells, to preserve their functions and, ultimately, lead to restoration of tissue integrity and transparency of the cornea.

Establishment of mouse model of neurotrophic keratopathy through TRPV1 neuronal ablation

Neurotrophic keratopathy (NK) is a challenging disease with the reduced innervation to the cornea. To establish a genetic and stable mouse model of NK, we utilized the TRPV1-DTR mice with intraperitoneal injection of diphtheria toxin (DT) to selectively eliminate TRPV1 neurons. After DT administration, the mice exhibited robust ablation of TRPV1 neurons in the trigeminal ganglion, accompanied with reduced corneal sensation and nerve density, as well as the decreased calcitonin-gene-related peptide (CGRP) and substance P levels. According to disease progression of TRPV1 neuronal ablation, tear secretion was reduced from day 3, which followed by corneal epithelial punctate lesions from day 7. From day 11 to day 16, the mice exhibited persistent corneal epithelial defects and stromal edema. By day 21, corneal ulceration and stromal melting were observed with the abundant inflammatory cell infiltration, corneal neovascularization, and enhanced cell apoptosis. Moreover, subconjunctival injection of CGRP delayed the NK progression with the characteristics of reduced severe corneal epithelial lesions and corneal inflammation. In addition, the impairments of conjunctival goblet cells, lacrimal gland, and meibomian gland were identified by the diminished expression of MUC5AC, AQP5, and PPARγ, respectively. Therefore, these results suggest that the TRPV1-DTR mice may serve as a reliable animal model for the research of NK pathogenesis.

Outcomes of N-butyl-2-Cyanoacrylate Tissue Adhesive Application in Corneal Perforation Disorders: Consecutive Case Series

INTRODUCTION

The purpose of this study was to report the success and long-term outcomes of cyanoacrylate tissue adhesive (CTA) application in the management of corneal perforation disorders.

METHODS

This retrospective case series describes the profile and outcomes of eyes that underwent CTA for corneal perforation over an 11-year period from January 2009 until January 2020 at a tertiary eye centre in the United Kingdom.

RESULTS

In total, 25 eyes underwent CTA application during the study period. Non-traumatic sterile corneal melt was responsible in more than half of the cases (56.0%; n = 14) followed by infection (32.0%; n = 8) and trauma (12.0%; n = 3). Median size of perforation was 2.0 mm (interquartile range, IQR 1.0-3.0). The most common anatomical location of corneal perforation was central (56.0%; n = 14). Ocular surface disease was seen in almost all eyes except two (92.0%; n = 23) with dry eye disease being the most common (48.0%; n = 12). Amongst 23 eyes that completed follow-up (median 27 months; IQR 9.5-46.5), single CTA application was successful in achieving intact globe in 13 (56.5%) eyes and repeat gluing sealed total of 20 (86.9%) eyes. Survival analysis showed cumulative success of 71.0% and 51.2% at 90 and 250 days, respectively. The CTA was retained in the eyes for median of 94.0 days (IQR 30.0-140.5). A total of five patients developed adverse events, including endophthalmitis (n = 2), following CTA application.

CONCLUSIONS

CTA was highly effective in sealing corneal perforations in acute setting and showed moderate long-term success. However, multiple applications are often required.

Epidemiological and microbiological profiles of microbial keratitis in a tertiary eye center in Eastern India (Bihar)

Purpose

To determine the demography, risk factors, and causative organisms of microbial keratitis (MK) in Bihar, an eastern state of India.

Design

Retrospective study.

Methods

We reviewed the demographic, clinical, and microbiological data of 2303 patients with MK (non-viral) presenting between January 2019 and December 2022.

Results

This study revealed a predominance of males (65.0%) compared to females (34.9%), with a mean age of 48.4 ± 16.5 years. The majority of patients (63.1%) presented after 2 weeks from the onset of symptoms. The most common risk factor observed was corneal injury (58.1%), followed by ocular surface diseases (13.6%) and diabetes mellitus (13.3%). The majority of patients (73.16%) were involved in agriculture. Prior to presentation, almost all patients (92%) had received topical antibiotics. Unsupervised use of topical corticosteroids was observed in 29.2% of the patients for the median duration of 3 days (odds ratio, 0.17). At presentation, the median size of corneal ulcers was 5 mm, the best-corrected visual acuity was less than 20/400 in 51.4% of patients, and corneal perforation was in 14% of patients. The smear and culture positivity rate were 75.4% and 47.9%, respectively. The common causative organism was fungus (48.8%), followed by bacteria (17.4%). Aspergillus spp. and Staphylococcus spp. were the most commonly identified organisms; a quarter of the patients (24.5%) remained unidentified. All bacteria showed good sensitivity to vancomycin.

Conclusion

MK is a significant cause of ocular morbidity in Bihar. The knowledge of epidemiology, risk factors, and microbiological profiles of MK can provide a valuable approach to disease prevention, diagnosis, and management.

Immunity and pain in the eye: focus on the ocular surface

Most ocular diseases are associated with pain. While pain has been generally considered a mere (deleterious) additional symptom, it is now emerging that it is a key modulator of innate/adaptive immunity. Because the cornea receives the highest nerve density of the entire body, it is an ideal site to demonstrate interactions between pain and the immune response. Indeed, most neuropeptides involved in pain generation are also potent regulators of innate and adaptive leukocyte physiology. On the other hand, most inflammatory cells can modulate the generation of ocular pain through release of specific mediators (cytokines, chemokines, growth factors, and lipid mediators). This review will discuss the reciprocal role(s) of ocular surface (and specifically: corneal) pain on the immune response of the eye. Finally, we will discuss the clinical implications of such reciprocal interactions in the context of highly prevalent corneal diseases.

Impact of COVID-19 Pandemic on Infectious Keratitis Outcomes: A Retrospective Multicenter Study in Tertiary Eye Hospitals of South India

PURPOSE

The purpose of this study was to report the adverse effects of the COVID-19 pandemic on the clinical outcomes of infectious keratitis in South India.

METHODS

Two hundred fifty-eight patients presented with infectious keratitis at 6 tertiary care centers when strict travel restrictions were in place from March 24 to May 31, 2020. Case records were collected retrospectively and analyzed for demographics, type of initial treatment, length of delay in presentation, microbiological diagnosis, clinical course, and final treatment outcome.

RESULTS

The mean age of the patients was 49.2 years, with most of them (61.2%) being male. Forty-one patients (15.9%) did not receive any treatment for at least a week after the onset of symptoms. One hundred eight patients (41.9%) presented with severe ulcer (32 had a frank perforation). Resolution of the infection was achieved only in 103 patients (45.6%). A total of 90 patients (39.8%) with ulcers had a perforation, yet only 29 patients (32.2%) could receive keratoplasty because of the unavailability of donor tissues. At the end of 6-month follow-up, 47 patients had anatomical failure (loss of globe) and 12 additional patients had functional failure (total permanent vision loss).

CONCLUSIONS

Delay in presentation and acute shortage of donor corneal tissues for emergency keratoplasty because of the COVID-19 pandemic had a grave impact, resulting in irreversible blindness in a significant number of patients.

Chlorhexidine gluconate 0.2% as a treatment for recalcitrant fungal keratitis in Uganda: a pilot study

OBJECTIVE

Fungal keratitis is a major ophthalmic public health problem, particularly in low-income and middle-income countries. The options for treating fungal keratitis are limited. Our study aimed to describe the outcomes of using chlorhexidine 0.2% eye-drops as additional treatment in the management of patients with recalcitrant fungal keratitis.

METHODS

This study was nested within a large cohort study of people presenting with microbial keratitis in Uganda. We enrolled patients with recalcitrant fungal keratitis not improving with topical natamycin 5% and commenced chlorhexidine 0.2%. Follow-up was scheduled for 3 months and 1 year. The main outcome measures were healing, visual acuity and scar size at final follow-up.

RESULTS

Thirteen patients were followed in this substudy. The patients were aged 27-73 years (median 43 years). Filamentous fungi were identified by microscopy of corneal scrape samples in all cases. Isolated organisms included Aspergillus spp, Fusarium spp, Candida spp, Bipolaris spp and Acremoninum spp. At the final follow-up, nine patients (75%) had healed; three had vision of better than 6/18. Three patients lost their eyes due to infection. In the remaining nine cases, corneal scarring was variable ranging from 4.6 to 9.4 mm (median 6.6 mm, IQR 5.9-8.0 mm); of these five had dense scars, three had moderate scars and one had a mild scar. None of the patients demonstrated signs of chlorhexidine toxicity during the follow-up.

CONCLUSION

Chlorhexidine 0.2% was found to be a useful sequential adjunctive topical antifungal in cases of fungal keratitis not responding to natamycin 5%, which warrants further evaluation.

The two-faced effects of nerves and neuropeptides in corneal diseases

Corneal nerves are instrumental to maintain cornea integrity through regulation of key physiological functions such as tear secretion, blink reflex, and neuropeptide turnover. Corneal nerve injury/stimulation can follow many insults including mechanical/chemical trauma, infections and surgeries. Nerve disruption initiates a process named neurogenic inflammation which leads to edema, pain, and recruitment and activation of leukocytes. Interestingly, leukocyte influx in the cornea can further damage nerves by releasing inflammatory mediators-including neuropeptides. The clinical outcome of neuroinflammation can be beneficial or detrimental to corneal integrity. On one side, it ensures prompt wound healing and prevents infections. On the other, prolonged and/or deranged neuroinflammation can permanently disrupt corneal integrity and impair vision. The cornea is an ideal site to study peripheral neuroinflammation and neurogenic inflammation since it receives the highest density of sensory nerves of the entire body. We will review the corneal nerve anatomy and neurochemistry, discuss the beneficial and detrimental effects of neurogenic inflammation in corneal wound healing, inflammatory processes, and pain. We will also examine the emerging remote impact of corneal nerve disruption on the trigeminal ganglion and the brain, highlighting the key role of neuropeptide Substance P. Finally, we will discuss the clinical relevance of such neuroinflammatory network in the context of severe and highly prevalent ocular diseases, including potential treatments.

Medical History, Clinical Features, Treatment Outcome and Its Predictors Among Infectious Keratitis Patients in Jimma University Medical Center, Southwest Ethiopia: Prospective Observational Study

BACKGROUND

Infectious keratitis is a major global cause of visual impairment and irreversible blindness among the corneal diseases. Its diagnosis and management remain getting challenge. The clinical and visual outcome remains poor in developing countries. The aim of this study was to determine treatment outcome and its predictors among patients with infectious keratitis.

METHODS

Prospective observational study was conducted among adult patients diagnosed with infectious keratitis at the Ophthalmology Department in Jimma University Medical Center from April 1 to September 30, 2019. The primary outcome indicator was response of the ulcer to empirical treatment. Ulcers that did not heal and required surgery had a poor outcome. Variables with a p-value of <0.25 were entered into a multivariate logistic regression model to determine the independent predictors of poor treatment outcome and variables with a p-value of <0.05 were considered statistically significant.

RESULTS

The research involved 131 adult patients. Eighty-seven (66.4%) were males. The mean age was 39.38 (±18.9) years. Eighty-three (63.4%) patients had poor treatment outcome. Mean length of hospital stay was 17.38 (±12.563) days. Poor visual outcome was observed among 71 (54.2%) participants. Evisceration was done for seven (5.3%) patients. Independent predictors of poor treatment outcome include perforation at admission (AOR=6.1, 95%CI: 1.5-25.1), presence of comorbidity (AOR=7.7, 95%CI: 2.16-27.3), poor adherence (AOR=5.3, 95%CI: 1.8-25.9), traditional medicine use (AOR=6.7, 95%CI: 1.8-25.4), ulcer depth >1/3 (AOR=7.6, 95%CI: 2.48-48.23) and farm workers (AOR=3.59, 95%CI: 1.09-11.77). Major complications occurred after admissions were perforation (14.5%), followed by endophthalmitis (7.63%) and corneal opacity (6.87%).

CONCLUSION AND RECOMMENDATION

Our study found high poor treatment outcomes and high poor visual outcomes. Presence of comorbidity, perforation at admission, traditional medicine use, working on a farm, poor adherence, and ulcer depth were the predictors of poor treatment outcome. This high poor outcome requires a nationwide interventional study and urgent intervention that may reach rural communities.

Clinical and Microbiological Profile of Bacterial and Fungal Suspected Corneal Ulcer at University of Gondar Tertiary Eye Care and Training Centre, Northwest Ethiopia

Background. A corneal ulcer is a major cause of monocular blindness in developing countries, including Ethiopia. Its etiology varies based on its geographical location and climatic conditions. Therefore, the main objective of this research was to assess the clinical and microbiological profile of suspected bacterial and fungal corneal ulcers at the Tertiary Eye Care and Training Centre at Gondar University. Methods. A cross-sectional hospital-based study of corneal ulcer cases was performed from February to October 2019. Sociodemographic and clinical data were collected using a standardized questionnaire. Corneal scrapings were used to classify bacterial and fungal pathogens. The specimens were inoculated on BHI media and sub-cultured on culture media for the separate cultivation of bacteria and fungi. Biochemical tests have been carried out to classify bacteria. Following CLSI, the antimicrobial resistance pattern of bacterial isolates was carried out. Wet mounting, Lactophenol cotton blue staining, and colony characteristics on SDA were used to classify fungal species. The data were analyzed with version 20 of the SPSS. Results. A total of 30 suspected bacterial and fungal keratitis patients have been enrolled in this study. The visual acuity presented in 90% of the affected eyes was in the category of blindness (<3/60). In 71% of the cases, clinically presumed risk factors were identified. Trauma was the most common risk factor found in 46% of cases, followed by keratitis exposure (13%). Of the corneal scrape tests, 76.6% were positive for bacteria and fungi. Fungi were identified in 53.3% of corneal ulcers followed by 33.3% of bacterial growth. The commonest fungi and bacteria isolated were Aspergillus species (69%) and S. aureus, respectively. The prevalence of Methicillin-resistant S. aureus (MRSA) was 2 (40%). The identified Pseudomonas species were susceptible to Gentamicin and Ciprofloxacin but resistant to Ceftriaxone. Conclusion. The primary microbial agents for corneal ulcers were fungi, and trauma was the most significant risk factor associated with corneal ulcers. To avoid chronic ocular morbidity and blindness, early identification of the etiologic agent and the provision of adequate management are recommended.

Epidemiology of Microbial Keratitis in Uganda: A Cohort Study

Purpose

To describe the epidemiology of Microbial Keratitis (MK) in Uganda.

Methods

We prospectively recruited patients presenting with MK at two main eye units in Southern Uganda between December 2016 and March 2018. We collected information on clinical history and presentation, microbiology and 3-month outcomes. Poor vision was defined as vision < 6/60).

Results

313 individuals were enrolled. Median age was 47 years (range 18–96) and 174 (56%) were male. Median presentation time was 17 days from onset (IQR 8–32). Trauma was reported by 29% and use of Traditional Eye Medicine by 60%. Majority presented with severe infections (median infiltrate size 5.2 mm); 47% were blind in the affected eye (vision < 3/60). Microbiology was available from 270 cases: 62% were fungal, 7% mixed (bacterial and fungal), 7% bacterial and 24% no organism detected. At 3 months, 30% of the participants were blind in the affected eye, while 9% had lost their eye from the infection. Delayed presentation (overall p = .007) and prior use of Traditional Eye Medicine (aOR 1.58 [95% CI 1.04–2.42], p = .033) were responsible for poor presentation. Predictors of poor vision at 3 months were: baseline vision (aOR 2.98 [95%CI 2.12–4.19], p < .0001), infiltrate size (aOR 1.19 [95%CI 1.03–1.36], p < .020) and perforation at presentation (aOR 9.93 [95% CI 3.70–26.6], p < .0001).

Conclusion

The most important outcome predictor was the state of the eye at presentation, facilitated by prior use of Traditional Eye Medicine and delayed presentation. In order to improve outcomes, we need effective early interventions.

The management of microbial keratitis within Uganda's primary health system: a situational analysis

Background: Microbial keratitis (MK) frequently leads to sight-loss, especially when the infection is severe and/or appropriate treatment is delayed. The primary health system as an entry point plays a central role in facilitating and directing patient access to appropriate care. The purpose of this study was to describe the capacity of primary health centres in Uganda in managing MK. Methods: We carried out a rigorous assessment of primary health centres and mid-cadre training schools in South Western Uganda. Through interviews, checklists and a picture quiz, we assessed capacity and knowledge of MK management. In addition, we interviewed the heads of all the mid-cadre training schools to determine the level of eye health training provided in their curricula. Results: In total, 163 health facilities and 16 training schools were enrolled. Of the health facilities, only 6% had an Ophthalmic Clinical Officer. Only 12% of the health workers could make a diagnosis of MK based on the clinical signs in the picture quiz. Although 35% of the facilities had a microscope, none reported doing corneal scraping. None of the facilities had a stock of the recommended first line treatment options for MK (ciprofloxacin and natamycin eye drops). Among the training schools, 15/16 had an eye health component in the curriculum. However, the majority (56%) of tutors had no formal expertise in eye health. In 14/16 schools, students spent an average of two weeks in an eye unit. Conclusions: Knowledge among health workers and capacity of health facilities in diagnosis and management of MK was low. Training for eye health within mid-cadre training schools was inadequate. More is needed to close these gaps in training and capacity.

Outcome of therapeutic penetrating keratoplasty in advanced infectious keratitis

Purpose

This study aimed to evaluate the anatomical, therapeutic, and functional outcome of therapeutic penetrating keratoplasty (TPK) in terms of success and failure.

Methods

In this retrospective study 57 eyes of 57 patients were reviewed. They had undergone TPK from December 2012 to June 2017. Data analyzed included the baseline demographic features and characteristics, preoperative diagnosis, and postoperative outcomes. The baseline characteristics included age, gender, laterality, indications of TPK, lens status, size of the recipient, grade of the graft, organisms identified, preoperative best corrected visual acuity (BCVA), secondary procedures, adjunctive surgical procedure, postoperative BCVA at last follow-up, intraocular pressure (IOP), and long-term complications of TPK. The ultimate outcome of TPK was observed in terms of anatomical, therapeutic, and functional outcome which indicated the success and failure.

Results

A total of 57 eyes of 57 with an age range of 2–76-year-old patients who underwent TPK were included in the study. Perforated corneal ulcer was a major indication of TPK in 32 (56.1%) cases. Anatomical success was obtained overall in 49 (85.96%) cases. Indications of TPK and preoperative visual acuity, complications of TPK, and ultimate graft clarity showed significant impact on the anatomical outcome (P = 0.03, P = 0.00, P = 0.00, and P = 0.05), respectively. The therapeutic and functional success was observed in 51 (89.47%) and 40 (70.17%) cases, respectively.

Conclusions

Perforated corneal ulcers was the major indication for TPK. Indications and complications significantly affect the anatomical, therapeutic, and functional outcome.

Epidemiology, risk factors, and clinical outcomes in severe microbial keratitis in South India

PURPOSE

Here, we report risk factors associated with outcome in severe bacterial keratitis (BK), fungal keratitis (FK), and Acanthamoeba keratitis (AK) in India.

METHODS

Prospective observational cohort study conducted in Aravind Eye Hospital, India. Adults presenting with severe microbial keratitis (MK) were enrolled (size ≥3 mm) and followed to 21 days post-enrolment. Ulcer clinical features were recorded at presentation. Outcomes by final visit were classified as good (completely healed or reduced infiltrate size) or poor (enlarged infiltrate size, perforated, or surgery performed).

RESULTS

Of 252 participants with severe MK, 191 had FK, 18 had AK, 19 had BK, 4 had mixed BK/FK, and 20 were microbiologically negative. Median age was 50 years (interquartile range [IQR]: 37-60 years), 64% were male, 63% were agriculturalists, and 45% had no formal education. Corneal trauma occurred in 72%, and median symptom duration before presentation was 7 days (IQR: 5-15 days). Clinical features associated with FK were feathery margins (p < 0.001), raised profile (p = 0.039), or dry surface (p = 0.007). Hypopyon was more likely in BK (p = 0.001) and ring infiltrate in AK (p < 0.001). Ulcers with poor outcome (n = 106/214) were more likely to be larger (odds ratio [OR]: 1.63, 95% confidence interval [CI]: 1.30-2.05, p < 0.001), involve the posterior cornea at presentation (OR: 2.31, 95% CI: 1.16-4.59, p = 0.017), involve Aspergillus sp. (OR: 3.23, 95% CI: 1.26-8.25, p = 0.014), or occur in females (OR: 2.04, 95% CI: 1.03-4.04, p = 0.04). Even after treatment, 34% (n = 76/221) had severe visual impairment by the final visit.

CONCLUSIONS

Severe MK occurred predominantly in agriculturalists post-corneal trauma and often had poor outcomes. Provision of community-based eyecare may allow earlier treatment and improve outcomes.

Outcomes of Infectious versus Sterile Perforated Corneal Ulcers after Therapeutic Penetrating Keratoplasty in the United States

Purpose. To compare the long-term outcomes of infectious versus sterile perforated corneal ulcers after therapeutic penetrating keratoplasty in the United States. Methods. The charts of 45 consecutive eyes that underwent primary therapeutic penetrating keratoplasty for a perforated corneal ulcer at a single center were retrospectively reviewed. The perforated ulcers were classified as infectious or sterile and the underlying demographics, clinical features, and 36-month outcomes were compared among the two groups. Results. Mean follow-up among subjects was 38.6 (±6.9) months. Patients presenting with sterile perforated ulcers were more likely to have a peripheral perforation location (p = 0.0333) and recurrence of the underlying disease condition (p = 0.0321), require adjunctive surgical measures in the immediate postoperative period (p < 0.0001), have reperforation after keratoplasty (p = 0.0079), have worse best corrected visual acuity (p = 0.0130), develop no light perception vision (p = 0.0053), and require enucleation/evisceration (p = 0.0252) when compared to the infectious perforated ulcer group. Conclusions. Sterile perforated corneal ulcers have a worse prognosis and may be more frequent than those caused by infectious disease in the United States compared to the developing world.

Angiopoietin 2 expression in the cornea and its control of corneal neovascularisation

PURPOSE

To define proangiogenic angiopoietin 2 (ANG2) expression and role(s) in human and mouse vascularised corneas. Further, to evaluate the effect of ANG2 inhibition on corneal neovascularisation (CNV).

METHODS

CNV was induced in FVB mice by means of intrastromal suture placement. One group of animals was sacrificed 10 days later; corneas were immunostained for ANG2 and compared with (i) mouse non-vascularised corneas and (ii) human vascularised and non-vascularised corneas. A second group of CNV animals was treated systemically with an anti-ANG2 antibody. After 10 days, the corneas were whole-mounted, stained for CD31 and LYVE1 and lymphatic/blood vessels quantified. In another set of experiments, the corneal basal Bowman membrane was either (i) removed or (ii) left in place. After 2 or 10 days the corneas were removed and immunostained for collagen IV, ANG2, CD31, LYVE1, CD11b and MRC1 markers.

RESULTS

In human beings and mice, ANG2 is expressed only in the epithelium, and, mildly, in the endothelium, of the avascular cornea. Instead, it is expressed in the epithelium, endothelium and stroma of vascularised corneas. Disruption of the Bowman membrane is associated with a significant increase of (i) ANG2 stromal expression and (ii) proangiogenic macrophage infiltration in the corneal stroma. Finally, blocking ANG2 significantly reduced hemangiogenesis, lymphangiogenesis and macrophage infiltration.

CONCLUSIONS

Balancing proper healing and good vision is crucial in the cornea, constantly exposed to potential injuries. In this paper, we suggest the existence of a mechanism regulating the onset of inflammation (and associated CNV) depending on injury severity.

Management of inflammatory corneal melt leading to central perforation in children: a retrospective study and review of literature

PURPOSE

To assess the outcome of early therapeutic penetrating keratoplasty (PKP) for corneal melt leading to perforation in children.

METHODS

Case notes of all the consecutive patients presenting with acute corneal perforation that underwent urgent therapeutic PKP between 2000 and 2010 to the practice of one of the authors, both NHS at Great Ormond Street Hospital for Children and private, were retrospectively reviewed. Onset of perforation, underlying cause, medical and surgical treatment, pre- and post-operative visual acuity, graft clarity, length of follow-up, and post-operative complications were recorded.

RESULTS

Four eyes of four consecutive patients (mean age of 9.5 years and median 8.5 years, range 4-17 years) were treated for acquired acute onset corneal perforations. There were three females and one male. Etiologies included herpes simplex keratitis secondary to immune recovery disease post bone marrow transplantation, acanthamoeba keratitis, recessive dystrophic epidermolysis bullosa, and blepharokeratoconjunctivitis with acne rosacea. Pre-operative visual acuity ranged from hand movements to 6/150. All the patients had severe anterior chamber inflammation. All eyes improved in visual acuity ranging from 6/9 to 6/18 with clear grafts at last follow-up. There was no recurrence of melt or perforation. Mean follow-up was 67 months (median 44 months).

CONCLUSION

PKP during the acute phase together with aggressive medical therapy and close follow-up may achieve good visual outcomes in children with corneal melt with perforation and should be considered. Waiting may sometimes allow the marked inflammatory response seen in children to cause irreversible structural and/or functional damage.

Microbial Profile of Corneal Ulcers in a Tertiary Care Hospital in South India

PURPOSE

To identify the prevalence and microbial profile of infectious keratitis in a tertiary eye care hospital, and to test for the in vitro antimicrobial resistance of the bacterial isolates.

METHODS

A total of 312 patients presenting to a tertiary eye care hospital with infected corneal ulcer were enrolled in this study. Their socio-demographic data and risk factors were recorded. Corneal scrapings collected from the edge of the ulcer were processed for direct gram stain and KOH mount. Culture was recovered on blood agar, chocolate agar, MacConkey agar and Sabouraud's dextrose (SDA) agar in multiple C shaped streaks. After overnight incubation, bacterial culture was followed by standard biochemical tests and antimicrobial sensitivity according to the clinical and laboratory standards institute (CLSI) guidelines. Inoculated SDA was inspected daily for up to 10 days and the growth was identified by its colony morphology, pigment production and lacto-phenol cotton blue mount examination.

RESULTS

Of 312 patients, a microbial etiology was established in 117 cases (37.5%). Of these, 72 (61.5%) were male. The age range of 41-60 years was the most affected group. Of 117 positive cases, 52 (44.5%) were bacterial, 58 (49.5%) were fungal and 7 (6%) patients showed mixed bacterial and fungal infection. The most common isolated fungus was Fusarium which was detected in 36 (31%) cases, followed by Aspergillus spp in 13 (11%) subjects. Staphylococcus aureus was the most common isolated bacteria. All Gram positive cocci were susceptible to vancomycin followed by gatifloxacin, whereas all Gram negative bacilli were susceptible to gatifloxacin.

CONCLUSION

Routine microbiological examination of patients with corneal ulcer is necessary in order to analyze and compare the changing trends of the etiology and their susceptibility patterns.

Filamentous fungal infections of the cornea: a global overview of epidemiology and drug sensitivity

Fungal keratitis is a serious suppurative, usually ulcerative corneal infection which may result in blindness or reduced vision. Epidemiological studies indicate that the occurrence of fungal keratitis is higher in warm, humid regions with agricultural economy. The most frequent filamentous fungal genera among the causal agents are Fusarium, Aspergillus and Curvularia. A more successful therapy of fungal keratitis relies on precise identification of the pathogen to the species level using molecular tools. As the sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster (rDNA) is not discriminative enough to reveal a species-level diagnosis for several filamentous fungal species highly relevant in keratitis infections, analysis of other loci is also required for an exact diagnosis. Molecular identifications may also reveal the involvement of fungal species which were not previously reported from corneal infections. The routinely applied chemotherapy of fungal keratitis is based on the topical and systemic administration of polyenes and azole compounds. Antifungal susceptibility testing of the causal agents is of special importance due to the emergence and spread of resistance. Testing the applicability of further available antifungals and screening for new, potential compounds for the therapy of fungal keratitis are of highlighted interest.

Resistant Microbial Keratitis in South Nile Delta, Egypt: Influence of Regional Risk Factors

PURPOSE

This study was conducted in an attempt to identify the regional, geographic, climatic, socioeconomic, and other risk factors for microbial keratitis in south Nile Delta, Egypt.

METHODS

This is a prospective cross-sectional study that was carried out on 340 eyes of 340 patients with microbial keratitis attending at the outpatient clinic of Ophthalmology Department of Menoufia University Hospital during a period of three years between March 2010 and March 2013.

RESULTS

Epidemiological factors, lines of management, and follow-up results were recorded and statistically analyzed and there were regional variations in the prevalence, risk factors, and outcome in resistant corneal ulcers.

CONCLUSION

Higher incidence of affections and complications has appeared in farmers, rural area residents, and illiterates which are considered the main predisposing factors for ulcer resistance. According to culture results, bacterial organisms (especially Staphylococcus aureus) were the main cause of resistant corneal ulcers.

Diversity of microbial species implicated in keratitis: a review

Background:

Microbial keratitis is an infectious disease of the cornea characterised by inflammation and is considered an ophthalmic emergency requiring immediate attention. While a variety of pathogenic microbes associated with microbial keratitis have been identified, a comprehensive review identifying the diversity of species has not been completed.

Methods:

A search of peer-reviewed publications including case reports and research articles reporting microorganims implicated in keratitis was conducted. Search engines including PubMed, Scopus and Web of Science with years ranging from 1950-2012 were used.

Results:

232 different species from 142 genera, representing 80 families were found to be implicated in microbial keratitis. Fungi exhibited the largest diversity with 144 species from 92 genera. In comparison, 77 species of bacteria from 42 genera, 12 species of protozoa from 4 genera and 4 types of virus were identified as the infectious agents. A comparison of their aetiologies shows reports of similarities between genera.

Conclusions:

The diversity of microbial species implicated in keratitis has not previously been reported and is considerably greater than suggested by incidence studies. Effective treatment is heavily reliant upon correct identification of the responsible microorganisms. Species identification, the risk factors associated with, and pathogenesis of microbial keratitis will allow the development of improved therapies. This review provides a resource for clinicians and researchers to assist in identification and readily source treatment information.

Intraocular cysticercosis: case series and comprehensive review of the literature

PURPOSE

To analyze the demographics and clinical characteristics in patients with intraocular cysticercosis.

METHODS

Retrospective case series and comprehensive literature review.

RESULTS

Intraocular cysticercosis was diagnosed in 21 of 21,079 patients (0.10%) seen by the uveitis service at Aravind Eye Hospital. At presentation, visual acuity was 20/200 or worse in 14 eyes (63.6%). Inflammation was unilateral in all but one patient (95.2%). The cyst was located in the vitreous cavity in 36.4% of eyes and in the subretinal space in 63.6% of eyes. In the literature review, most patients were affected unilaterally (98.5%); visual acuity at presentation was 20/200 or worse in 82.3% of eyes; and the cyst was located in the vitreous cavity in 59.5% of eyes.

CONCLUSIONS

Intraocular cysticercosis usually affects young patients unilaterally. The cyst may be in either the vitreous cavity or the subretinal space, and visual acuity at presentation is often poor.

Corticosteroids for bacterial corneal ulcers

AIMS

The aim of the study was to conduct a preliminary clinical trial to assess whether adjunctive topical corticosteroids improve outcomes in bacterial keratitis and, if no difference was found, to determine the feasibility and sample size necessary for conducting a larger trial to answer this question.

METHODS

In this single centre, double-masked clinical trial, 42 patients with culture-confirmed bacterial keratitis at Aravind Eye Hospital in India were randomised to receive either topical prednisolone phosphate or placebo. All patients received topical moxifloxacin. The primary outcome was best spectacle-corrected visual acuity (BSCVA) at 3 months, adjusting for enrolment BSCVA and arm. Other pre-specified outcomes included re-epithelialisation time, infiltrate/scar size and adverse events.

RESULTS

Compared with placebo, patients in the steroid group re-epithelialised more slowly (hazard ratio 0.47, 95% CI 0.23 to 0.94). There was no significant difference in BSCVA or infiltrate/scar size at 3 weeks or 3 months. To have 80% power to detect a two-line difference in acuity, 360 cases would be required.

CONCLUSIONS

Although corticosteroid treatment resulted in a statistically significant delay in re-epithelialisation, this did not translate to a significant difference in visual acuity, infiltrate/scar size or adverse events. To assess the effect of steroids on acuity, a larger trial is warranted and feasible.

Clinical outcomes of keratitis

OBJECTION

To analyse the patient, clinical and microbiological variables associated with poor outcomes from keratitis in patients presenting to a major public hospital in Australia.

METHODS

A retrospective audit of the records of all patients who had a corneal scraping in 5 years at Princess Alexandra Hospital (Brisbane, Australia) was carried out. The outcome of a patient's episode of keratitis was classified as poor if they had final visual acuity of 6/60 or worse; had vision loss during treatment; or a complication of keratitis; or needed surgical intervention.

RESULTS

A final outcome was established in 207 cases during the 5-year period. Final vision of 6/12 or better was found in 48% (100) of cases while a poor outcome was seen in 28% (58). Linear regression showed poor outcomes were directly associated with age (P < 0.001) and disease severity (P < 0.001). Univariate analysis indicated that poor outcomes were more likely in patients who had had prior ocular surgery (P = 0.005) or ocular surface disease (P = 0.01) and were also associated with presenting visual acuity of worse than 6/60 (P < 0.001) and isolation of Streptococcus pneumoniae (P = 0.002). While patients with traumatic keratitis, contact lens-related keratitis or negative corneal cultures (P = 0.009) were more likely to have good outcomes. Multivariate analysis showed that the relative risk of a patient having a poor outcome was 4.3x (CI 2.0-9.5) if they had severe keratitis, 4.1x (CI 1.8-9.5) if they had keratitis related to ocular surface disease and 3.8x (CI 1.8-8.3) if they were over 50 years old.

CONCLUSIONS

An outcome of poor vision, vision loss during treatment, surgical intervention or complication of keratitis is more likely in patients with severe keratitis, keratitis related to prior ocular surface disease or older age.

Infectious keratitis

PURPOSE OF REVIEW

Infectious keratitis is a medical emergency. Improper management can lead to marked loss of vision. This review identifies recent trends in the study of infectious keratitis.

RECENT FINDINGS

A multicountry outbreak of Fusarium keratitis emphasizes that contact lens wear is a major risk factor for infectious keratitis. Acanthamoeba and fungal keratitis are the most expensive forms of infectious keratitis to treat. Noninvasive methods and molecular techniques have improved diagnosis of infectious keratitis. Fortified topical antibiotics and fluoroquinolones are still the mainstay of bacterial keratitis therapy. Voriconazole and new routes of administration of conventional antifungals appear promising for fungal keratitis. Antivirals and amelioration of host inflammatory response are promising for viral keratitis; the host response is also crucial in pathogenesis of Pseudomonas aeruginosa keratitis. Trauma-induced bacterial and fungal keratitis and contact lens-associated keratitis are preventable entities.

SUMMARY

Improved modalities of diagnosis and treatment have improved the outcome of infectious keratitis, but therapy of acanthamoebal, fungal and P. aeruginosa keratitis is still a challenge. Effective strategies must neutralize potential risk factors and counter host response overactivity without impairing killing of infecting microorganisms. Trauma-induced bacterial and fungal keratitis can be prevented.