Microbial keratitis complicating penetrating keratoplasty

Loose suture-related ocular surface inflammation and activation of conjunctiva-associated lymphoid tissue in patients after keratoplasty

The purpose of this study is to evaluate loose suture-related inflammation and activation of conjunctiva-associated lymphoid tissue (CALT) in patients after keratoplasty. The patients who were treated with keratoplasty at the First Affiliated Hospital of Harbin Medical University between 2015 and 2022 were recruited into the study. We evaluated the time and location of loose suture development in patients after keratoplasty. In addition, in vivo confocal microscopy was used to evaluate the activation of CALT and the accumulation of inflammatory cells around loose sutures. Meso Scale Discovery assay detection kits were used to evaluate the inflammatory cytokines in the tears of patients before and after the loose suture was removed. In this study, we collected the information from 212 cases (212 eyes) who had PK (126 eyes) and DALK-treated (86 eyes) for corneal transplantation, including 124 males and 88 females, aged 14-84 years old. The average age was 50.65 ± 16.81 years old. Corneal sutures were more prone to loose at 3 months and 6 months after keratoplasty, and the frequent sites were at 5 and 6 o'clock. An increased number of inflammatory cells could be observed around the loose sutures than normal sutures (P < 0.001). In CALT, the density of diffuse lymphocytes (P < 0.001), follicles (P < 0.001), and parafollicular lymphocytes (P < 0.001) were higher and the central reflection of the follicles (P < 0.001) was stronger when suture loosening happened. The levels of inflammatory cytokines such as IL-1β (P = 0.003), IL-8 (P = 0.012), and TNF-α (P < 0.001) were higher in the tears of the patients with loose sutures. The activation of CALT was partly settled after removing the loose sutures. In conclusion, loose sutures after corneal transplantation can lead to increased infiltration of inflammatory cells, activation of CALT, and increased secretion of inflammatory cytokines in the tears of patients. Regular follow-up to identify and solve the problem in time can avoid suture-related complications.

Post-Keratoplasty Microbial Keratitis in the Era of Lamellar Transplants-A Comprehensive Review

Microbial keratitis in a post-transplant cornea should be considered a distinct entity from microbial keratitis in a non-transplant cornea. Firstly, the use of immunosuppressive treatments and sutures in corneal transplants changes the etiology of keratitis. Secondly, corneal transplant has an impact on corneal biomechanics and structure, which facilitates the spread of infection. Finally, the emergence of lamellar transplants has introduced a new form of keratitis known as interface keratitis. Given these factors, there is a clear need to update our understanding of and management strategies for microbial keratitis following corneal transplantation, especially in the era of lamellar transplants. To address this, a comprehensive review is provided, covering the incidence, risk factors, causes, and timing of microbial keratitis, as well as both clinical and surgical management approaches for its treatment in cases of penetrating and lamellar corneal transplants.

Infectious keratitis following corneal transplantation: A long-term cohort study

BACKGROUND

To assess the long-term incidence and risk factors for post-keratoplasty infectious keratitis (IK), associated ocular pathogens, and antibiotic resistance profiles.

METHODS

Cohort study including 2553 consecutive penetrating, endothelial, and anterior lamellar keratoplasties performed between 1992 and 2020. Medical and microbiological records of patients clinically diagnosed with IK were retrospectively reviewed.

MAIN OUTCOME MEASURES

cumulative incidence of IK, infectious agent species, and antibiotics resistance profiles.

RESULTS

The average follow-up time after transplantation was 112 ± 96 months. Eighty-nine IK episodes were recorded; microbiological tests were positive in 55/89 (62%). The cumulated incidence of postoperative IK was 5.50%/10.25% at 10/20 years. The occurrence of at least one episode of IK after transplantation was associated with lower graft survival in the long term (p < 0.0001). Rejection risk (adjusted Hazard Ratio, 2.29) and postoperative epithelial complications (HR, 3.44) were significantly and independently associated with a higher incidence of postoperative IK. Infectious agents included 41 bacteria, 10 HSV, 6 fungi, and 1 Acanthamoeba. The rate of antibiotic resistance was 0% for vancomycin, 13% for fluoroquinolones, 20% for rifamycin, 59% for aminoglycosides, and 73% for ticarcillin. In 41% of cases, patients were under prophylactic topical antibiotics before the infectious episode. Topical antibiotics were significantly associated with increased resistance to penicillin, carbapenems, and aminoglycosides.

CONCLUSION

IK (mainly bacterial) is a frequent complication of corneal transplantation in the long term. Vancomycin and fluoroquinolones can be considered as first-line treatments. Prolonged postoperative antibiotic preventive treatment is not advisable as it may increase antibiotic resistance.

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.

[Penetrating keratoplasty]

Penetrating keratoplasty is a tissue transplant commonly performed around the world. For over a century, penetrating keratoplasty has been the standard method of treatment for many corneal diseases causing visual impairment. Recently, lamellar anterior keratoplasty (LAK) or lamellar endothelial (LEK) have become preferable options, resulting in fewer complications and faster functional rehabilitation. While penetrating keratoplasty is less frequently indicated, in favor of these lamellar grafts, it has not necessarily become obsolete, and its use remains appropriate for its chosen indications. Functional results are good if the indication for surgery is properly assessed, therapeutic precautions are taken in view of complications, and follow-up aims to improve initial refractive results as needed.

Update on Suture Techniques in Corneal Transplantation: A Systematic Review

Effective suturing remains key to achieving successful outcomes in corneal surgery, especially anterior lamellar keratoplasty and full thickness transplantation. Limitations in the technique may result in complications such as wound leak, infection, or high astigmatism post corneal graft. By using a systematic approach, this study reviews articles and conducts content analysis based on update 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria). The aim of this paper is to summarize the state of the art of corneal suturing techniques for every type of corneal transplant and patient age and also their outcomes regarding astigmatism and complications. Future developments for corneal transplantation will be also discussed. This is important because especially the young surgeon must have knowledge of the implications of every suture performed in order to achieve consistent and predictable post-operative outcomes and also be aware of all the possible complications.

Post-keratoplasty Infectious Keratitis: Epidemiology, Risk Factors, Management, and Outcomes

Post-keratoplasty infectious keratitis (PKIK) represents a unique clinical entity that often poses significant diagnostic and therapeutic challenges. It carries a high risk of serious complications such as graft rejection and failure, and less commonly endophthalmitis. Topical corticosteroids are often required to reduce the risk of graft rejection but their use in PKIK may act as a double-edged sword, particularly in fungal infection. The increased uptake in lamellar keratoplasty in the recent years has also led to complications such as graft-host interface infectious keratitis (IIK), which is particularly difficult to manage. The reported incidence of PKIK differs considerably across different countries, with a higher incidence observed in developing countries (9.2-11.9%) than developed countries (0.02-7.9%). Common risk factors for PKIK include the use of topical corticosteroids, suture-related problems, ocular surface diseases and previous corneal infection. PKIK after penetrating keratoplasty or (deep) anterior lamellar keratoplasty is most commonly caused by ocular surface commensals, particularly Gramme-positive bacteria, whereas PKIK after endothelial keratoplasty is usually caused by Candida spp. Empirical broad-spectrum antimicrobial treatment is the mainstay of treatment for both PKIK, though surgical interventions are required in medically refractory cases (during the acute phase) and those affected by visually significant scarring (during the late phase). In this paper, we aim to provide a comprehensive overview on PKIK, encompassing the epidemiology, risk factors, causes, management and outcomes, and to propose a treatment algorithm for systematically managing this challenging condition.

Microbial keratitis and clinical outcomes following penetrating and endothelial keratoplasty

PURPOSE

The goal of this study was to review the incidence, risk factors and outcomes of microbial keratitis after penetrating keratoplasty (PK) and endothelial keratoplasty (EK).

METHODS

The electronic medical records at Wills Eye Hospital were queried for cases of microbial keratitis following PK or EK performed between 1 May 2007 and 1 September 2018. Charts were reviewed to obtain demographic data, transplant characteristics, details of microbial keratitis, graft survival and clinical outcomes.

RESULTS

During the study period, 2098 transplants were performed in 1601 patients. Of these, 1267 (60.4%) were PKs and 831 (39.6%) were EKs. We identified 86 (4.1%) cases of subsequent microbial keratitis. The incidence of microbial keratitis after PK was significantly higher than after EK (5.9% versus 1.3%; p = 0.005). Furthermore, the rate of infection was higher after repeat transplants (either PK or EK) compared to initial keratoplasties (5.5% versus 3.4%; p = 0.02). Twenty-six (32.1%) grafts remained clear at most recent follow-up after microbial keratitis, and the proportion of clear grafts was higher after EK than PK (66.7% versus 27.8%; p = 0.03).

CONCLUSION

Rates of microbial keratitis were significantly higher after PK compared to EK, and repeat transplantation was a risk factor for microbial keratitis. To the best of our knowledge, there is no prior study in the literature evaluating microbial keratitis rates after PK and EK and comparing outcomes.

Microbial Keratitis in Corneal Transplants: A 12-Year Analysis

Purpose

To investigate the frequencies, trends, and in vitro drug susceptibilities of the causative pathogens in corneal transplant microbial infections in Manchester Royal Eye Hospital.

Methods

Corneal scrape results recorded by the microbiology service between 2004 and 2015 were extracted from an established database. This microbiological data was matched with a separate database of all corneal transplant procedures performed in our centre over this time period. Patient records were examined to collect specific patient data and to confirm the diagnosis of microbial keratitis.

Results

A total of 1508 grafts had been performed at our centre in this period. 72 episodes of graft microbial keratitis were identified from 66 eyes that had undergone keratoplasty procedures. Mean age was 56, and 51% of subjects were male. Ninety-three percent of microbial keratitis episodes occurred in penetrating keratoplasty procedures and 6% in deep anterior lamellar keratoplasty procedures. No endothelial grafts presented with infections throughout this time period. Of the 79 organisms identified, 73% were gram positive, 23% gram negative and 4% fungi. With regard to gram-positive organisms, vancomycin and gentamicin showed 100% and 91% susceptibility, respectively. Ofloxacin had a resistance rate of 13.7%. In terms of gram-negative organisms, gentamicin and chloramphenicol showed 100% sensitivity, with cefuroxime showing 69%. Resistance rates were less than 15% in all tested gram-negative antimicrobials.

Conclusion

This paper describes the largest collection of corneal transplant infections identified within the UK. This finding may aid clinicians in predicting possible causative organisms for microbial keratitis and aid antibiotic choice.

Distribution of Microbial Keratitis After Penetrating Keratoplasty According to Early and Late Postoperative Periods

Objectives:

The aim of this study was to investigate the distribution of microbial agents in the early and late postoperative periods in patients with microbial keratitis (MK) after penetrating keratoplasty (PK).

Materials and Methods:

The records of 36 patients who were clinically diagnosed as having MK after PK were retrospectively reviewed. Culture results were obtained from microbiology records and the organisms that were produced were noted. A case was deemed as viral keratitis based on the clinical appearance, negative cultures, and response to antiviral treatment. Keratitis development times were evaluated in 2 categories: early (within the first year) and late (after year 1) postoperative period. Mann-Whitney U and Kruskal-Wallis tests were used to compare numerical variables that did not show normal distribution and chi-square test was used to compare categorical variables.

Results:

The majority of MK cases were of bacterial origin (55.5%, n=20), followed by viral (41.7%, n=15) and fungal (2.8%, n=1). Of the 15 cases of early postoperative MK, 10 were bacterial, 4 were viral, and 1 was fungal; however, among cases of late postoperative MK, 10 were bacterial and 11 were viral. The majority (65%) of early and late bacterial infections were caused by gram-positive strains (most commonly staphylococci). Gram-positive bacteria caused keratitis significantly earlier than gram-negative bacteria (p=0.037). Viral and gram-negative bacterial MK was more frequent in the late postoperative period, but the difference was not statistically significant.

Conclusion:

In our study, bacterial keratitis was more common in post-keratoplasty MK than viral and fungal keratitis. Gram-positive bacteria were the most common causative agents. The increased incidence of gram-negative bacterial agents and viral keratitis in the late postoperative period can be explained by long-term topical steroid use.

Factors predicting long-term changes in refraction after lamellar keratoscleroplasty in children with limbal dermoids

OBJECTIVES

The objective of this study is to determine the factors that predict long-term changes in refraction after lamellar keratoscleroplasty in paediatric patients with limbal dermoids.

METHODS

A retrospective study of 66 children with limbal dermoids who had lamellar keratoscleroplasty correction with more than 1-year follow-up. Univariate and multivariate regression analyses were performed to investigate factors associated with the long term in refractive parameters, including spherical equivalent, astigmatism, and mean keratometry. The change value was defined as the postoperative refractive value minus the preoperative refractive value. The lower the value of changes, the more satisfied the effects on the correction of the preoperative refraction.

RESULTS

A total of 66 patients (mean surgical age: 3.5 ± 2.1 years) were assessed with at least 1-year follow-up. Amblyopia treatment duration was the only independent factor predicting the long-term changes in spherical equivalent between baseline and last follow-up visit (β = -0.030, P < 0.001). Lesion encroachment on the central and paracentral cornea (β = 0.502, P = 0.024), suture-related complications (β = 1.571, P < 0.001) and graft rejection (β = 0.983, P = 0.035) were significantly correlated with long-term changes in astigmatism. The long-term changes in refraction were not correlated with surgical age, lesion size, lesion depth, steroid-induced high intraocular pressure and changes in mean keratometry.

CONCLUSION

Suture-related complications and graft rejection should be carefully observed and appropriately treated in order to avoid the possible postoperative increase in astigmatism, especially for patients with lesion encroachment on the central and paracentral cornea. The long-duration amblyopia treatment after surgery appears to have a better correction effect on spherical equivalent in the long term, compared with astigmatism.

Approaches toward enhancing survival probability following deep anterior lamellar keratoplasty

The greatest advantage of deep anterior lamellar keratoplasty over full-thickness corneal transplantation is the elimination of graft failure caused by endothelial rejection. Despite this advantage, a deep anterior lamellar keratoplasty graft can fail because of several factors, such as complications related to the donor-recipient interface, graft epithelial abnormalities, graft vascularization, stromal graft rejection, and recurrence of herpetic keratitis. Increased deep anterior lamellar keratoplasty graft survival is mainly built upon optimization of the ocular surface to provide a hospitable environment for the graft. Any predisposing factors for graft epithelial abnormalities, corneal neovascularization, and preexisting vernal keratoconjunctivitis should be identified and treated preoperatively. Prompt recognition and appropriate treatment of interface-related complications and stromal graft rejection usually result in good anatomic outcomes, with no detrimental effects on vision.

Microbial Keratitis After Penetrating Keratoplasty

PURPOSE

To report the incidence, microbiological profile, graft survival, and determining factors of microbial keratitis after penetrating keratoplasty (PK).

DESIGN

Observational case series.

METHODS

The study involved 51 patients (52 eyes) who were treated at a single tertiary referral center during a 10-year period. Retrospective chart review included medical records of all patients diagnosed with microbial keratitis after penetrating keratoplasty at the National Taiwan University Hospital between January 2000 and December 2009. The main outcome measures were incidence of graft infection, microbial profile, and graft survival status.

RESULTS

There were 871 PKs performed and 67 episodes in 52 eyes of culture-positive microbial keratitis during the study period. There were 32 infectious episodes (47.8%) in the first year post-PK and 35 episodes (52.2%) after the first year post-PK. Forty-four gram-positive bacterial isolates (57.9%), 17 gram-negative bacterial isolates (22.4%), and 15 fungal isolates (19.7%) were found. Twenty-three (34.3%) grafts remained clear after the infection episode with a mean follow-up of 1127 days (range, 25-3962 days). There was no difference in graft survival rate regarding the original indication of PK or offending pathogen. Suture-related infection was associated with decreased risk of graft failure (P = .02), while the factor associated with increased risk of graft failure was usage of antiglaucoma agents (P = .01).

CONCLUSION

Infectious keratitis after penetrating keratoplasty leads to a high graft failure rate. Such complications can occur before or after the first year post-PK.

Shifting trends in microbial keratitis following penetrating keratoplasty in Taiwan

To investigate the clinical and microbiological profiles from microbial keratitis following penetrating keratoplasty (PKP) in a tertiary referral center in Taiwan, the medical records of 648 consecutive patients (648 eyes) undergoing PKP between January 2003 and December 2007 were retrospectively reviewed. Patients who subsequently sustained microbial keratitis were enrolled and analyzed for potential risk factors, clinical manifestations, microbiological profiles, complications, graft survival, and final visual outcome. A total number of 42 corneal graft infections (6.5%) were recruited. Mean interval between corneal transplantation and graft infection was 12 ± 9.5 months. Potential risk factors included suture-related problems (31.0%), lid abnormalities (23.8%), persistent epithelial defect (23.8%), contact lens use (14.3%), dry eye (11.9%), and prior rejection episodes (4.8%). Lesions were discovered mostly at the donor-recipient junction ([DRJ] 45.2%). Positive cultures were identified in all of the morbid eyes, of which Pseudomonas aeruginosa was the most common pathogen (38.1%). Despite mandatory hospitalization and topical fortified antibiotics management, complications ensued such as graft failure (71.4%), hypopyon (21.4%), corneal perforation (14.3%), wound dehiscence (11.9%), and endophthalmitis (4.8%). The visual outcome was dismal that graft clarity was achieved in only 12 eyes (28.6%), and that final visual acuity deteriorated to less than 20/200 in 28 eyes (66.7%). In conclusion, microbial keratitis following PKP is a devastating event that severely impairs graft survival rate and postoperative visual outcome which usually occur within the first postoperative year. The incidence of post-PKP microbial keratitis has generally decreased in recent years whilst P. aeroginosa prevails as the leading cause of graft infection in our hospital. Close follow-up by ophthalmologists and elevated self-awareness of patients for at least one year are always encouraged to prevent late-onset infection.

Factors Affecting Treatment Outcome of Graft Infection Following Penetrating Keratoplasty

Purpose

To evaluate the factors affecting treatment outcome of graft infection following penetrating keratoplasty (PKP).

Methods

In this retrospective study, 28 patients who underwent PKP between January 2005 and January 2013 and who were diagnosed with graft infection were classified into a treatment success group or a treatment failure group. Demographic and clinical characteristics, as well as the results of the microbiologic investigation, were analyzed and compared. A subsequent binary logistic regression analysis was performed to identify the prognostic factors affecting treatment outcome.

Results

Graft infection occurred at a mean of 38.29 ± 36.16 months (range, 1 to 96 months) after PKP. Seventeen patients developed bacterial keratitis, and 11 patients developed fungal keratitis. Overall, of the 28 patients, nine (32.1%) were classified in the treatment failure group. Multivariate analysis identified pre-existing graft failure (p = 0.019), interval longer than 72 hours between donor death and PKP (p = 0.010), and fungal infection (p = 0.026) as significant risk factors for treatment failure.

Conclusions

Pre-existing graft failure, extended interval between donor death and PKP, and fungal infection were important risk factors for treatment failure of graft infection following PKP.

Clinical and microbiological profile of post-penetrating keratoplasty infectious keratitis in failed and clear grafts

PURPOSE

To comparatively evaluate the clinical and microbiological profiles and treatment outcome of cases with post-penetrating keratoplasty (PK) infectious keratitis in failed and clear grafts.

DESIGN

Retrospective, matched cohort study.

METHODS

All cases of infectious keratitis following penetrating keratoplasty admitted to the Royal Victorian Eye and Ear Hospital, Melbourne, between January 1998 and December 2008 were identified through a retrospective medical chart review. Cases without any surface sutures were selected and divided into 2 groups, microbial keratitis with pre-existing graft failure and microbial keratitis in clear graft on presentation. Demographic, clinical, and microbiological profiles of cases in both groups were analyzed and compared.

RESULTS

Patients in the failed-graft group were older (P = .004) and had an early onset of graft infection (P = .049), compared with patients in the clear-graft group. All patients in the failed-graft group were on long-term corticosteroid drops at the time of presentation (vs 76% in clear-graft group; P = .005). Moraxella sp was more frequently isolated in the failed-graft group (30.4%) compared with the clear-graft group (8%). A higher number of cases in the clear-graft group required surgical intervention in the form of corneal gluing and therapeutic corneal transplantation compared with the failed-graft group (P = .03).

CONCLUSIONS

Prolonged use of corticosteroid eye drops is a major risk factor for the occurrence of postkeratoplasty infectious keratitis in failed and clear grafts. Infections in failed grafts occur earlier as compared to clear grafts, and indolent organisms like Moraxella are prevalent in patients with failed grafts in Australia.

Microbial keratitis after penetrating keratoplasty: impact of sutures

PURPOSE

To determine the impact of presence or absence of sutures in cases with post-penetrating keratoplasty (PKP) microbial keratitis.

DESIGN

A 10-year retrospective chart review of post-PKP patients admitted with microbial keratitis at the Royal Victorian Eye and Ear Hospital, Melbourne, between January 1998 and December 2008 was undertaken.

METHODS

Patients were categorized in 2 groups, "sutures present" and "sutures absent." Main parameters evaluated were clinical and microbiological profile and treatment outcome.

RESULTS

One hundred and twenty-two episodes of microbial keratitis were noted in 101 patients: 71 (58.2%) with sutures present and 51 (41.8%) with sutures absent. Overall, pseudophakic bullous keratopathy was the most common indication for keratoplasty (P=.92). Ocular surface disorder was the commonest risk factor associated with the occurrence of infection in both groups (P=.17). Infections caused by Moraxella sp. (P=.001) were significantly more common in the "sutures absent" group. Surgical interventions were required for 47 episodes (39%), with corneal gluing performed in significantly higher number of cases in the "sutures absent" group (40% vs 15%; P=.05). Multivariate analyses did not reveal any significant associations. Final mean visual acuity outcome was poorer in the "sutures absent" group (logMAR 2.10 ± 0.92 vs 1.76 ± 0.96; P=.04).

CONCLUSIONS

Corneal graft infections, in the presence and absence of sutures, share similar indications and risk factors. However, infections caused by indolent microorganisms were more prevalent in grafts without sutures. This group of patients required a higher number of surgical interventions in the form of corneal gluing and the overall visual outcome was poor.

Incidence, occurrence rate, and characteristics of suture-related corneal infections after penetrating keratoplasty

PURPOSE

To report the incidence, occurrence rate, and characteristics of suture-related infections after penetrating keratoplasty (PK).

METHODS

Patients who underwent PK at our institution between January 1, 2002, and July 1, 2006, were cross-referenced with patients diagnosed with corneal infections between January 1, 2002, and July 1, 2007. All patient charts were reviewed retrospectively for occurrence of suture-related infections, duration of follow-up, and clinical characteristics.

RESULTS

Of the 487 PKs performed in 412 patients, 22 eyes of 22 patients developed postoperative corneal infections. Of these, 5 eyes were identified as having suture-related graft infections, yielding an occurrence rate of 1.0%. The average follow-up was 3.46 years per PK, yielding an incidence of 2.96 infections per 1000 PK-years. The mean interval from surgery to infection was 8 months (range: 3-23 months). All culprit sutures were in the interpalpebral zone. No patients were using topical antibiotics at the time of infection, and all patients were using topical corticosteroid drops. Cultured organisms included Staphylococcus aureus (3 cases), coagulase-negative Staphylcoccus (1 case), and S. viridans (1 case). In 2 patients with isolated corneal involvement, topical moxifloxacin was initiated, and the patients responded favorably. In 3 patients with corneal infection and an associated hypopyon or endophthalmitis, vitreous biopsy, intravitreal injections of antibiotics, and fortified topical antibiotics were used. One patient required a repeat PK as a result of the infection. Two eyes eventually became phthisical.

CONCLUSIONS

The rate of suture-related infections after PK may be lower than previously reported. In our patients, suture-related infections all occurred within the first 2 years after surgery, and some of them resulted in significant morbidity, underscoring the importance of patient identification of symptoms and early clinical recognition.

Fungal keratitis in the United Kingdom 2003-2005

PURPOSE

To describe the incidence and current management of fungal keratitis in the United Kingdom.

METHODS

Cases were identified prospectively through the British Ophthalmologic Surveillance Unit (BOSU) from December 2003 to November 2005. Questionnaire data were requested at diagnosis and at 6 months follow-up. Inclusion criteria were a positive culture or microsopic proof from a scraping or biopsy, and a normal residence in the United Kingdom.

RESULTS

Data were available on 39 confirmed cases at diagnosis and 34 cases at follow-up. The minimum average annualised incidence was 0.32 (95% CI, 0.24-0.44) cases per million individuals. In 22 cases (56%), only Candida was isolated and 14 of these (63%) had prior ocular surface disease treated with topical steroid. A filamentary fungus infection was more common in male patients (P=0.02), often following trauma, and the differences in risk factors between types of fungal infection was statistically significant (P<0.001). One case had a mixed yeast and filamentary fungus infection. The most frequent initial topical therapies were amphotericin B (38%) or econazole (28%). In addition, oral fluconazole was used in 11 (31%) patients and oral itraconazole in six (15%). At follow-up, the vision in 15 eyes (44%) was <6/60 including three eyes eviscerated.

CONCLUSIONS

This study provides data on the minimum incidence of fungal keratitis in the United Kingdom. It provides evidence of frequent delay in diagnosis after presentation to eye departments, inconsistent management, and poor outcome. Issues that can now be addressed.

Fungal keratitis in London: microbiological and clinical evaluation

PURPOSE

To review cases of culture-positive fungal keratitis seen at Moorfields Eye Hospital over a 13-year period to January 2007.

METHODS

Isolates were identified retrospectively from laboratory reports. The clinical records were reviewed. The fungal type, risk factors for infection, in vitro sensitivity, and clinical outcome were recorded.

RESULTS

There were 66 isolates from 65 patients (men, 53.8%). Forty (60.6%) of the isolates were subspecies of Candida. The average interval from the onset of keratitis to confirmation of fungal infection was 3.4 weeks (median, 1.0 week; range, 0-16 weeks). Prior ocular surface disease (OSD) or a penetrating keratoplasty (PK) was present in 38 (97.4%) patients with Candida infection, and 29 (74.4%) patients with Candida infection were using topical steroid at the time of diagnosis. The principal risk factors for filamentary fungal infection were trauma (8 cases, 30.8%) or cosmetic contact lens wear (8 cases, 30.8%), with OSD or a prior PK each present in 5 (19.2%) cases. The difference in the proportions of risk factors between the 2 fungal groups was statistically significant (P < 0.000). The visual outcome was similar between groups, and at final review, 27 (41.5%) eyes had a visual acuity of < or = 1/60 and 3 (4.6%) eyes were eviscerated. In vitro sensitivity testing showed full or part sensitivity in 100% of 55 isolates tested against econazole, 87.9% of 58 isolates tested against amphotericin, 75% of 40 isolates tested against itraconazole, and 100% of 20 isolates tested against voriconazole.

CONCLUSIONS

Candida was the principal isolate, usually from eyes with OSD or a prior PK treated with topical steroids.

Graft failure: II. Ocular surface complications

Risk factors for corneal transplantation failure include both immunologic factors, such as graft rejection, corneal neovascularization, and peripheral anterior synechiae, as well as non-immunologic factors, such as ocular surface disorders (OSD) and glaucoma. This review highlights the necessity of having healthy ocular surface epithelia, tears, and eyelids. It presents different types of OSD, their underlying pathology, and their impact on native cornea and corneal grafts. In addition, a range of proposed donor and surgical factors influencing surface integrity following corneal transplant are addressed. Current medical and surgical research, both pre- and post-operative that promise to further improve the outcome of corneal grafts in the context of OSD are discussed.

Microbial keratitis following corneal transplantation

PURPOSE

To determine the predisposing risk factors and analyse the clinical and microbiological profiles of microbial keratitis following corneal transplantation.

METHODS

A retrospective analysis was done of hospital records of all patients who presented with microbial keratitis in the corneal graft between July 2000 and June 2005 at the Corneal Unit of Royal Victorian Eye and Ear Hospital, Melbourne, Australia.

RESULTS

Eighty-one episodes of infection were identified in 62 patients over a 5-year period. Thirteen patients had multiple episodes of infection. The mean age of the patients was 70 +/- 16 years (range: 22-92 years). The median time interval between the graft and infection was 17 months (range: 6 days to 385 months). Twenty-two (35%) episodes of primary infection were related to sutures. The associated predisposing risk factors were failed graft (40%), dry eye (18%), Herpes simplex keratitis (8%), and ocular surface disease (8%). Forty-seven (76%) cases were culture positive for bacteria. Ten cases were positive for Herpes simplex virus (HSV) during presentation.

CONCLUSION

Failed graft is a long-term risk factor for graft infection in addition to ocular surface disease and H. simplex keratitis. All the predisposing risk factors increase the risk of recurrent graft infection.

Bacterial keratitis after primary pediatric penetrating keratoplasty

PURPOSE

To determine the prevalence, microbiological profile, and prognosis for bacterial keratitis after primary pediatric penetrating keratoplasty (PKP).

DESIGN

Retrospective case series.

METHODS

Retrospective review of all cases of primary PKP performed in children 12 years of age or younger at the King Khaled Eye Specialist Hospital between January 1, 1990 and December 31, 2005 and inclusion of all postoperative cases of culture-positive, bacterial keratitis.

RESULTS

Culture-positive bacterial keratitis developed in 35 (17.3%) of 202 primary keratoplasties. Gram-positive organisms were cultured in 91.4% of infected eyes and accounted for 77.6% of isolates. Streptococcus pneumoniae was the most common organism. No eyes achieved a final visual acuity of 20/40 or better, while 65.7% had hand motions or worse.

CONCLUSIONS

Bacterial keratitis after pediatric keratoplasty is a serious complication that is associated with a high risk of graft failure and poor visual outcome.

Bacterial Keratitis after Penetrating Keratoplasty

PURPOSE

To determine the incidence, microbiological profile, graft survival, and factors influencing graft survival after the development of bacterial keratitis after penetrating keratoplasty (PK).

DESIGN

Retrospective case series.

PARTICIPANTS

One hundred two patients (102 eyes) treated at a single center during a 5-year period.

METHODS

Retrospective review of the medical records of every patient treated for culture-positive keratitis between January 1, 1998 and December 31, 2002 who previously had undergone penetrating keratoplasty at the King Khaled Eye Specialist Hospital.

MAIN OUTCOME MEASURES

Graft survival and visual outcome.

RESULTS

There were 2103 PKs performed and 102 (4.9%) cases of culture-positive keratitis during the study period. There were 168 bacterial isolates, of which 140 (83.3%) were gram positive, 28 (16.7%) were gram negative, and 1 (0.6%) was acid fast. Only 38 (37.3%) grafts remained clear after a mean follow-up of 985 days (range, 82-2284). The best graft survival was in eyes with PK for keratoconus (83.7%), whereas the poorest grat survival was for previously failed grafts (5.6%). By Kaplan-Meier analysis, there was an immediate steep decline in graft survival to 54.9%, followed by a slow decline to 47.2% by 1 year and 35.8% after 4 years. Factors associated with an increased risk of graft failure were the surgical indication for PK (P<0.001), increasing patient age (P = 0.004), smaller donor (P = 0.001) and recipient (P = 0.0003) graft size, history of previous microbial keratitis (P = 0.02) or endothelial rejection episodes (P = 0.02), and coexisting glaucoma (P = 0.001). The visual outcome was > or =20/40 in only 8 (8.2%) eyes and better than 20/200 in only 21 (21.6%) eyes.

CONCLUSION

The development of bacterial keratitis after PK is a serious complication that is associated with a high incidence of graft failure and poor visual outcome.

Infectious keratitis following keratoplasty

Infectious keratitis following corneal transplantation is one of the leading causes of failure of a corneal graft. The incidence of graft infection is variable, with developing countries having a higher incidence. The majority of the graft infections occur within 1 year of the corneal transplantation. Suture-related problems and persistent epithelial defect are the most common risk factors predisposing to graft infection. Pneumococcus species and Staphylococcus aureus have been found to be the commonest microorganisms in the developed world, whereas Staphylococcus epidermidis is the most often detected microorganism in corneal graft infection in the developing world. The early identification of predisposing risk factors in patients and their appropriate management at the earliest may prevent the occurrence of graft infection and might improve graft survival. Visual prognosis in eyes with post-keratoplasty graft infection is poor even after optimal therapy and there is a high rate of graft decompensation.

Ulcerative Keratitis Caused by Haemophilus Influenzae

PURPOSE

To report the clinical course, treatments, antibiotic sensitivities, and visual outcomes for eyes with ulcerative keratitis caused by Haemophlilus influenzae.

METHODS

The medical records of 10 patients with culture-proven H. influenzae-associated corneal ulcer in a tertiary referral center in a 5-year period (1998-2003) were retrospectively reviewed.

RESULTS

The median age was 61 years (range, 2-83 years). The mean follow-up time was 9.4 months (range, 2-31 months). Risk factors such as previous surgeries (5), herpes simplex keratitis (2), leukoma adherens with calcification (1), and exposure keratitis (1) were identified in 9 patients. In vitro testing of the H. influenzae isolates showed that 6 of 10 were resistant to ampicillin; all were sensitive to amoxicillin/clavulanic acid, ceftriaxone, and cefuroxime. All cases responded well to medical antibiotic treatment. Final best spectacle-corrected visual acuity ranged from no light perception to 20/30.

CONCLUSION

H. influenzae is a rare cause of corneal ulceration. Predisposing factors for infection are usually present. Accurate diagnosis and treatment may preserve ocular integrity and visual acuity.

Amniotic Membrane Transplantation for Persistent Corneal Ulcers and Perforations in Acute Fungal Keratitis

PURPOSE

To report the therapeutic effect and complications of amniotic membrane transplantation (AMT) in acute fungal keratitis.

METHODS

Diagnosis of fungal keratitis was confirmed by cultures in 23 eyes of 23 patients. The indications to perform AMT were to promote reepithelialization in non-healing ulcers or to prevent corneal perforation. Antifungal agents were administered throughout the whole course of hospitalization. Repeated cultures were performed immediately before AMT. The main outcome measurements were epithelial healing rate, necessity of therapeutic penetrating keratoplasty (TPK), and persistence of infection.

RESULTS

During a mean follow-up time of 20.6 months +/- 23.22 (6-65 months) AMT was performed during the active phase of the keratitis (fungal culture was still positive) in 16 patients (69.6%), and during the inactive phase (fungal culture negative) in 7 patients (30.4%). Single-layer AMT was performed in 17 patients, and double-layer AMT was performed in 6 patients with corneal perforation and anterior chamber collapse. Complete epithelialization was observed in 12 patients (75%) in the active group and in 7 patients (100%) in the inactive group. Treatment failure requiring TPK was experienced in 4 patients (25%) in the active group. Persistent fungal keratitis was noted in 2 patients (8.7%) in that group. The final visual acuity improved in 17 cases, worsened in 2 cases, and remained unchanged in 4 cases. Twelve of the 23 eyes (52.2%) in this study preserved useful vision (20/400 and better) with or without subsequent surgeries.

CONCLUSION

AMT is effective in promoting epithelialization and preventing corneal perforations in acute fungal keratitis, and there is no risk of rejection. However, the risk of persistent or recurrent infection necessitates continued antifungal treatment and patient monitoring.

Successful Topical Application of a New Antifungal Agent, Micafungin, in the Treatment of Refractory Fungal Corneal Ulcers

PURPOSE

To report the efficacy of topical application of a new antifungal agent, micafungin (MCFG), in the treatment of yeast-related corneal ulcers.

DESIGN

Noncomparative interventional case reports.

PARTICIPANTS

Three patients with yeast-related corneal ulcer after keratoplasty recalcitrant to conventional antifungal treatment for 4 weeks were recruited in this study.

METHODS

Topical 0.1% antifungal MCFG eye drops were applied in 3 patients with yeast-related corneal ulcer every hour while awake until epithelialization. After epithelialization, the frequency of eye drops was reduced to 5 times a day. MCFG eye drops were discontinued 1 month after the disappearance of stromal infiltration in each case. The patients underwent best corrected visual acuity (BCVA) measurements, slit-lamp examination, fluorescein-dye staining, and anterior segment photography. Corneal scrapings and cultures of surgical materials were also performed.

MAIN OUTCOME MEASURES

Changes in ulcer size, stromal infiltration, fluorescein dye staining, and BCVA were looked for.

RESULTS

All corneal ulcers epithelialized within 14 days after commencement of application of 0.1% MCFG eye drops. Yeasts were detected from corneal smears in all eyes. Two cases revealed positive culture isolates for Candida albicans and Candida parapsilosis. No recurrence of fungal keratitis was observed in any of the cases throughout the follow-up periods.

CONCLUSION

Topical 0.1% MCFG eye drops seem to be an effective and a promising option in the treatment of refractory yeast-related corneal ulcers.

Penetrating keratoplasty for macular corneal dystrophy

PURPOSE

To determine the prognosis of penetrating keratoplasty (PK) for macular corneal dystrophy (MCD).

DESIGN

Single-center, retrospective, interventional, noncomparative case series.

PARTICIPANTS

One hundred forty-one patients (229 eyes) with MCD.

INTERVENTION

Retrospective review of the medical record of every patient who underwent primary PK for histopathologically confirmed MCD at the King Khaled Eye Specialist Hospital between January 1, 1983 and December 31, 2002 and for whom at least 12 months of follow-up is available.

MAIN OUTCOME MEASURES

Visual acuity (VA), graft survival, and postoperative complications.

RESULTS

After a mean follow-up period of 5.9+/-3.8 years (range, 1-17), the mean best-corrected VA was 20/50. At the most recent visit, 206 (90.0%) grafts were clear, and 23 (10.0%) had failed. Probabilities of graft survival were 98.1% at 1 year, 89.8% at 5 years, 82.1% at 10 years, and 74.1% at 15 years. There was a statistically significant increased likelihood of graft failure if the patient was older than 40 years at the time of surgery (P<0.00003). The differences in graft failure between patients older than 40 and those younger were not attributable to statistically significant differences in duration of follow-up, donor age, or donor endothelial cell counts. Corneal endothelial rejection episodes occurred in 47 (20.0%) grafts, but resulted in irreversible graft failure in only 8 (3.5%) eyes. Eighteen (27.3%) of 66 eyes with a recipient size of > or =7.5 mm developed a graft rejection episode, compared with 27 (16.6%) of 163 eyes with a recipient size of <7.5 mm (P = 0.04). Microbial keratitis occurred in 14 (6.1%) grafts and was more likely to occur in patients over 40 (14.0% vs. 3.0%, P = 0.01). Clinically significant recurrence was observed in 12 (5.2%) grafts, after a mean interval of 84+/-48.2 months, and was directly related to patient age (P = 0.04) and inversely related to donor graft size (P = 0.04).

CONCLUSIONS

Good visual results and excellent graft survival can be achieved after PK for MCD. The risk of graft failure is higher in patients older than 40 years.

Photochemical keratodesmos as an adjunct to sutures for bonding penetrating keratoplasty corneal incisions

PURPOSE

To evaluate the benefit of photochemical keratodesmos (PKD) in acute wound closure of penetrating keratoplasty (PKP) corneal incisions in vivo.

SETTING

Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA.

METHODS

Penetrating keratoplasty incisions were performed in both eyes of 6 New Zealand white rabbits, followed by application of 1.5 mM rose bengal dye at the wound edges. The incision in 1 eye of each rabbit was irradiated with neodymium:YAG laser light at 532 nm and fluence of 40 J/cm2; the contralateral control eye was untreated. Intraocular pressure at which fluid leaked at the edges (IOPL) was determined immediately after surgery.

RESULTS

The mean IOPL was 410 mm Hg +/- 70 (SD) in the PKD-treated eyes and 250 +/- 150 mm Hg in the unirradiated eyes. The difference was statistically significant by paired t test (P<.05).

CONCLUSIONS

Photochemical keratodesmos may be a useful adjunct to sutures for approximating PKP corneal incisions in the immediate postoperative period. This process does not induce high temperature, and thus denaturation can be avoided and structural integrity restored.

Microbial Keratitis Following Lamellar Keratoplasty

OBJECTIVE

To determine the predisposing factors, etiologic agents, and clinical and visual outcomes in infectious keratitis following lamellar keratoplasty (LK).

METHODS

One hundred thirty-five eyes (135 patients) that had undergone LK were retrospectively analyzed for the occurrence of infectious keratitis following LK. The parameters evaluated were predisposing factors, seasonal variation, indications and type of LK, time interval between LK and infection, site and depth of infection, etiologic organisms, type of treatment, outcome in terms of graft status, secondary surgery, visual acuity, and the donor tissue profile.

RESULTS

The incidence of infectious keratitis following LK was 11.11%. The most significant predisposing factor was persistent epithelial defect (3 eyes) and suture abscesses (3 eyes). Most cases occurred between May and August (9/15). Twelve cases developed infection within 2 weeks of surgery (80%). Seven cases (7/15) occurred with onlay grafts, 6 with inlay grafts, and 2 with large-diameter LK. Cultures of corneal scrapings were positive in 11 eyes (73.3%), and the most common isolated organism was coagulase-negative Staphylococcus (CNS). Only 2 eyes responded to medical therapy, and graft sloughing occurred in 9 cases. Six eyes underwent penetrating keratoplasty to either salvage the integrity of globe or for visual rehabilitation of cases where infection resulted in corneal opacity.

CONCLUSIONS

Infections after LK may not be amenable to antimicrobial therapy and may necessitate the removal of the graft or a therapeutic penetrating keratoplasty.

Therapeutic penetrating keratoplasty in severe fungal keratitis using cryopreserved donor corneas

AIMS

To investigate whether cryopreserved donor cornea could be used for therapeutic penetrating keratoplasty (PKP) to eradicate the infection, obviate complications, and preserve anatomical integrity in severe fungal keratitis.

METHODS

In this retrospective, consecutive case series, 45 eyes of 45 patients with severe fungal keratitis, which exhibited anterior chamber collapse, corneal perforation, and/or large suppurative corneal infiltrate, received therapeutic PKP after removal of the infected corneal tissue, irrigation of the anterior chamber by 0.2% fluconazole solution, iris dissection of fibrinoid membrane, and iridectomy and therapeutic PKP using corneas cryopreserved at -20 degrees C.

RESULTS

Among 45 eyes, 39 eyes (86.7%) were successfully eradicated the fungal infection without recurrence and maintained their anatomical integrity without any complication. Four of 45 eyes (8.9%) showed postoperative rise of intraocular pressure, of which three were controlled with subsequent antiglaucoma surgeries, whereas one eye needed additional antiglaucoma medications. Two of 45 eyes (4.4%) were enucleated because of uncontrollable fungal infection and secondary retinal detachment, respectively. 23 eyes received subsequent optical PKP and, among them, 21 maintained clear corneal grafts and two suffered from graft failure due to allograft rejections.

CONCLUSION

Cryopreserved donor corneas are effective substitutes in therapeutic PKP to control severe fungal corneal infection and preserve the global integrity, and may offer additional advantages over conventional PKP in reducing allograft rejection, eradicating fungal infection during the postoperative period, and improving the success of optical PKP for visual rehabilitation.

Clinico-microbiological correlation of suture-related graft infection following penetrating keratoplasty

PURPOSE

To report the clinical and microbiological profiles of suture-related graft infections following penetrating keratoplasty.

DESIGN

Interventional case series.

METHODS

The medical and microbiology records of all patients who presented with suture-related graft infections and were seen between January 1999 and December 2001 were reviewed.

RESULTS

Of 105 patients (105 eyes) who developed corneal infiltrates following penetrating keratoplasty, 37 patients (24 optical and 13 therapeutic) were identified as having suture-related graft infection. The median onset of infiltrates after penetrating keratoplasty was 87 days for 31 patients who presented within one year. Gram-stained smears of corneal scrapings were positive in 27 (73%) of 37 patients, whereas cultures were positive in 32 (only bacteria, 30; mixed bacteria and fungi, 2). Thirty-seven isolates were obtained from 32 patients (gram-positive bacteria, 32; gram-negative bacteria, 3; fungus, 2). All gram-positive isolates were sensitive to cefazolin, chloramphenicol, and vancomycin, whereas one of three gram-negative isolates (Pseudomanas species) was resistant to all the antibiotics tested. Of 32 patients, 30 (82%) responded satisfactorily to medical management.

CONCLUSIONS

Suture-related graft infections are usually caused by bacteria that are sensitive to ciprofloxacin, cefazolin, and gentamicin, and the patients respond satisfactorily to medical therapy.

Epicorneal aspergilloma after penetrating keratoplasty

PURPOSE

To report an epicorneal aspergilloma in a postkeratoplasty patient with a bandage soft contact lens.

METHODS

Case report of a 77-year-old postkeratoplasty patient who presented with an epicorneal mass under a bandage soft contact lens placed for a nonhealing epithelial defect. On removal of the contact lens, a 4 x 4-mm placoid mass fell free from the corneal surface and was sent for culture and histopathology.

RESULTS

Gram stain demonstrated septated branching hyphae, and cultures confirmed the diagnosis of Histopathologic sections of the epicorneal mass revealed a full-thickness aspergilloma.

CONCLUSION

Contact lens removal and aggressive antimycotic treatment resulted in epithelial healing and resolution of the keratomycosis. The patient remained stable for 6 months followed by a successful repeat penetrating keratoplasty.

Deep suturing technique for penetrating keratoplasty

PURPOSE

To evaluate the effect of a new suturing technique on postkeratoplasty visual rehabilitation time and refractive error.

METHODS

Penetrating keratoplasty was performed on 17 eyes with keratoconus using a modified suturing technique. A donor button 8.0 mm in diameter was sutured into a 7.75-mm recipient bed with both deep and superficial sutures. The deep sutures consisted of either a single 16-bite 10-0 nylon running suture (n = 7) or eight interrupted 10-0 nylon cross-stitches (n = 10). These sutures were passed into the mid-stroma of the donor cornea and exited through the donor endothelium, then passed through the endothelium of the recipient cornea and exited from its mid-stroma. Thereby all parts of the deep sutures remained below the corneal surface. To further secure the surgical wound, in each case a running 16-bite 10-0 nylon superficial suture was also placed. Care was taken to maintain the bites of the superficial suture above the level of the deep sutures. The superficial suture was removed 3 months after surgery. Vision and refraction were recorded 1 day and 1 month postoperatively and 1 and 3 months after suture removal. A paired Student test was used to verify the significance of changes in visual acuity and refraction recorded at different examination times.

RESULTS

As early as 1 month after surgery, spectacle best-corrected visual acuity 20/40 or more and refractive astigmatism less than 4 diopters (D) were recorded in each eye and maintained with two exceptions at the later examination times. In two patients, postoperative astigmatism increased from 4.5 to 5 D after suture removal.

CONCLUSIONS

Deep suturing allowed quick visual rehabilitation while minimizing postkeratoplasty astigmatism in the patients with keratoconus operated on in this series.

The relationship between first postoperative day epithelial status and eventual health of the ocular surface in penetrating keratoplasty

PURPOSE

To determine a possible relationship between donor epithelial status on the first postoperative day after keratoplasty and the eventual health of the corneal surface.

METHODS

We analyzed 91 patients who underwent penetrating corneal transplantation between January 1998 and January 2000, monitoring the epithelial status of the corneas with fluorescein staining using slit-lamp biomicroscopy. Recipient pre- and postoperative variables and donor characteristics were recorded. Macroepithelial defects were classified into three groups according to the extent of the epithelial defect. The results on the first postoperative day were compared with the first and third operative month. Donor and recipient variables were compared with the epithelial status on the first and third month as well.

RESULTS

On the first postoperative day, 64.84% of the patients had epithelial defects, 10.99% had defects at the 1-month postoperative visit, and none had defects at the third month. Graft recipients with macroepithelial defects in the first postoperative month were older, had a higher prevalence of blepharitis, higher prevalence of inadequate eye hydration, and slightly increased corneal sensation compared with the group without epithelial defects; however, none of these trends were statistically significant. Patients with macroepithelial defects in the first postoperative month received older donor tissue, and the average preservation-to-surgery time was longer. These donor variables, however, were not significant statistically (p value >0.10) in determining outcome of the epithelial status at the first or third months.

CONCLUSIONS

Our results suggest that the epithelial status on the first postoperative day is not predictive of surface integrity at 1-month postoperative (p value is 0.2676 for the likehood ratio test). The epithelial status on the first postoperative day is not predictive of the status of the third month after keratoplasty, because none of the 91 patients had epithelial defects after 3 months.

Risk factors for graft infection in India: a case-control study

AIM

To study the demographic, clinical, and microbiological profile and the risk factors for graft infection following penetrating keratoplasty.

METHODS

50 eyes of 50 consecutive patients with graft infection after an optical penetrating keratoplasty were included as cases; 50 eyes of 50 patients with no graft infection were included as controls. The main variables evaluated in this study included the clinical and microbiological profile, sociodemographic status, suture related problems, persistent epithelial defects, and ocular surface disorders.

RESULTS

Cultures were positive in 43 (86%) eyes and Staphylococcus epidermidis (67.4%) was the most common organism isolated. Infection could be resolved with treatment in 37 (74%) eyes. In eight (16%) eyes the graft melted and a repeat penetrating keratoplasty had to be performed. Only 6% of the cases could achieve a best corrected visual acuity of 6/18 or better after resolution of the infection. In multivariate logistic regression analysis persistent epithelial defect (OR (95% CI): 3.0 (1.17 to 8.33)), suture related problems (OR (95% CI): 3.6 (1.39 to 9.25)), and ocular surface disorders (OR (95% CI): 2.4 (0.93 to 6.03)) were found to be statistically significant risk factors for graft infection following an optical penetrating keratoplasty.

CONCLUSIONS

Staphylococcus epidermidis is the commonest organism responsible for post-keratoplasty microbial keratitis. Persistent epithelial defects, suture related problems, and ocular surface disorders are the major risk factors predisposing to graft infection.