Infectious keratitis after penetrating keratoplasty]

PURPOSE: To investigate the prevalence of microbial keratitis, predisposing risk factors, the spectrum of pathogens and the prognosis for graft survival and visual outcome in patients who developed microbial keratitis following penetrating keratoplasty (PK). MATERIAL: and methods: We reviewed 16 cases (15 patients) of microbial keratitis after PK. In all cases, corneal scrapings were obtained and microbiologically analyzed. Efficacy of treatment was evaluated by anatomical (clarity of graft) and visual recovery. RESULTS: Principal indications for PK were pseudophakic bullous keratopathy (50%) and microbial keratitis in the previous graft (25%). Sixty-three per cent of infections occurred within 1 year of PK. Principal predisposing risk factors were suture-related problems (44%) and microbial keratitis in the previous graft (25%). All of the scrapings were positive according to the microbiological evaluation with gram-positive cocci (64%), gram-positive rods (12%), fungi (18%), and Acanthamoeba (6%). We found 1 case of polymicrobial infection. Best visual and anatomical results were observed in nonadvanced cases and/or these treated early. After medical and surgical treatments, 8 patients (50%) had a clear graft and 10 patients (63%) had visual acuity less than 20/200. CONCLUSION: Postoperative control of risk factors and early recognition of infectious complications may decrease the incidence of severe microbial keratitis after PK.     

Profile of sight‐threatening infectious keratitis: a prospective study

Purpose: To prospectively study patients presenting with sight‐threatening corneal ulcers with a view to identify the predisposing factors, causative organisms, clinical signs and treatment outcomes. Methods: Prospectively, over 3‐year period, all cases with serious infective keratitis presenting to Queens Medical Hospital in Nottingham, UK, were recruited. Detailed information on the aetiology, culture results, signs & symptoms, the treatment given and the patient’s response was collected and statistically analysed. Results: One hundred and forty‐three eyes of 129 patients were enrolled. Thirty‐one patients were managed as out‐patients, and 98 were treated as in‐patients. The mean duration of admission was 9 ± 13 days but was significantly higher in older patients and in Acanthamoeba keratitis cases. The important risk factors were ocular surface disease (32%), contact lens wear (26%) and previous ocular surgery (20%). Old age, deep infiltration, steroid use and poor initial vision were risk factors for prolonged course of treatment in bacterial keratitis. Corneal scrapings were done in 89% of the cases, but positive results were obtained only in 41.7%. Staphylococcus aureus was the most common isolated bacteria (18.8%). Acanthamoeba and Pseudomonas aeruginosa were the second and third common causative organisms (16.6% and 15%, respectively). Overall, 8.3% needed corneal grafting, which survived in 83.3% and eradicated infection in 100%. Conclusion: Microbial keratitis is an important cause of ocular morbidity. Previous ocular disease is an important predisposing factor. Old age, steroid use and poor presenting visual acuity are important prognostic indicators. Corneal grafting is an effective option for managing recalcitrant corneal infections.     

Moraxella keratitis: predisposing factors and clinical review of 95 cases

AIM: To analyse the clinical presentation, identify predisposing risk factors and evaluate the outcome of treatment of Moraxella keratitis. METHODS: A retrospective analysis was carried out of culture-proved cases of Moraxella keratitis from hospital records during a 10-year period (from December 1995 to November 2005) at the Corneal Unit of the Royal Victorian Eye and Ear Hospital, Melbourne, Australia. RESULTS: 95 episodes of Moraxella keratitis were identified in 92 patients. 3 (3.2%) patients had recurrent keratitis. The mean age of the patients was 70 (range 17-93) years. Multiple predisposing factors were identified in 23 (24%) eyes, including corneal graft (n = 15), previous herpes keratitis (n = 15) and eye lid diseases (n = 15). Adjunctive procedures were carried out in 42 eyes. These included botulinum toxin injection (n = 17), tarsorraphy (n = 12), penetrating keratoplasty (n = 8), enucleation (n = 3), tissue adhesive and bandage contact lens (n = 4), and conjunctival flap (n = 5). Polymicrobial infection was present in 17 eyes. Final visual acuity was counting finger or less in 25 (26%) eyes. CONCLUSIONS: Local ocular predisposing factors play a major role in Moraxella keratitis. This infection has a poor visual outcome attributable to both the nature of the infection and the predisposing factors.     

Corneal infection in Shandong peninsula of China: a 10-year retrospective study on 578 cases

AIM: To determine the epidemiological characteristics, clinical signs, laboratory findings, and outcomes in patients with corneal infection in Shandong peninsula of China. METHODS: The medical records of 578 inpatients (578 eyes) with corneal infection were reviewed retrospectively for demographic characteristics, risk factors, seasonal variation, clinical signs, laboratory findings, and treatment strategy. Patient history, ocular examination findings using slit-lamp biomicroscopy, laboratory findings resulted from microbiological cultures, and treatment. RESULTS: Fungal keratitis constituted 58.48% of cases of infectious keratitis among the inpatients, followed by herpes simplex keratitis (20.76%), bacterial keratitis (19.03%) and acanthamoeba keratitis (1.73%). The most common risk factor was corneal trauma (71.80%). The direct microscopic examination (338 cases) using potassium hydroxide (KOH) wet mounts was positive in 296 cases (87.57%). Among the 298 fungal culture-positive cases, Fusarium species were the most common isolates (70.47%). A total of 517 cases (89.45%) received surgical intervention, including 255 (44.12%) cases of penetrating keratoplasty, 74 (12.80%) cases of lamellar keratoplasty which has become increasingly popular, and 77 cases (13.32%) of evisceration or enucleation. CONCLUSION: At present, infectious keratitis is a primary corneal disease causing blindness in China. With Fusarium species being the most commonly identified pathogens, fungal keratitis is the leading cause of severe infectious corneal ulcers in Shandong peninsula of China.     

Microbial keratitis following penetrating keratoplasty.

PURPOSE: To investigate the prevalence of microbial keratitis, predisposing risk factors and treatment modalities in patients who developed keratitis following penetrating keratoplasty (PK). PATIENTS AND METHODS: The records of 285 patients who had undergone PK between January 1991 and December 1995 in a tertiary care center were reviewed. Patients who developed postoperative microbial keratitis were evaluated for predisposing risk factors, microbiological etiology, response to broad spectrum antibiotic therapy and subsequent PK. Patients were mainly treated with fortified topical antibiotics with or without repeat PK. RESULTS: Of the 285 patient records reviewed, microbial keratitis developed in 21 eyes of 21 patients (7.4%). Seventy-one percent of infections occurred within 6 months after grafting. Keratitis initially began from the donor-recipient border in 16 cases (76.2%) and were central or paracentral in 5 patients. Predisposing risk factors included loose or exposed suture (9), suture removal (1), persistent epithelial defect (3), graft failure (3), contact lens wear (1), Stevens-Johnson syndrome (1). Fifteen (71.4%) patients were culture-positive consisting of Streptococcus pneumoniae (7), Staphylococcus aureus (5), Pseudomonas aureginosa (2), and Hemophilus influenzae (1). Forty-three percent of patients were successfully treated with medical therapy only. Seven patients underwent second PK for visual rehabilitation and 4 for tectonic purposes. After medical and surgical therapy, graft clarity was achieved in 17 (81%) of patients. CONCLUSIONS: The microbial keratitis following PK is a major postoperative problem affecting the long term prognosis. Careful selection of patients, and preoperative and postoperative control of risk factors, may decrease the frequency of this complication. Several factors, including loose or exposed sutures, epithelial defects, ocular surface disorders, and graft failure, may predispose patients to develop microbial keratitis following PK.     

Antimicrobial management of presumed microbial keratitis: guidelines for treatment of central and peripheral ulcers

AIMS—To determine the quantitative relation between the major risk factors for microbial keratitis of previous ocular surface disease and contact lens wear and central and peripheral infiltration, often associated with ulceration, in order to establish a rational chemotherapeutic management algorithm.
METHODS—Data from 55 patients were collected over a 10 month period. All cases of presumed microbial keratitis where corneal scrapes had been subjected to microbiological examination were included. Risk factor data and laboratory outcome were recorded. Antimicrobial regimens used to treat each patient were documented.
RESULTS—57 episodes of presumed microbial keratitis were identified from 55 patients, 24 male and 31 female. There were 30 central infiltrates and 27 peripheral infiltrates of which 28 were culture positive (73% of central infiltrates, 22% of peripheral infiltrates). 26 patients had worn contact lenses of whom 12 had culture positive scrapes (9/14 for central infiltrates, 3/12 for peripheral infiltrates). 31 patients had an ocular surface disease of whom five previous herpes simplex virus keratitis patients developed secondary bacterial infection. Anterior chamber activity and an infiltrate size  4 mm² were more common with culture positive central infiltrates than peripheral infiltrates (χ² test = 11.98, p<0.001).
CONCLUSIONS—Predisposing factors for "presumed" microbial keratitis, either central or peripheral, were: ocular surface disease (26/57 = 45.6%), contact lens wear (26/57 = 45.6%), and previous trauma (5/57 = 8.8%). Larger ulceration (4 mm²) with inflammation was more often associated with positive culture results for central infiltration. None of these four variables (contact lens wear, ocular surface disease, ulcer size, anterior chamber activity) were of intrinsic value in predicting if a peripheral infiltrate would yield identifiable micro-organisms. Successful management of presumed microbial keratitis is aided by a logical approach to therapy, with the use of a defined algorithm of first and second line broad spectrum antimicrobials, for application at each stage of the investigative and treatment process considering central and peripheral infiltration separately.

Keywords: ulcerative keratitis; antimicrobials; ulcers     

Corneal infection in mucosal scarring disorders and Sj?gren's syndrome

We reviewed 69 episodes of microbial keratitis occurring over an 11-year period in 56 patients with a mucosal scarring disorder or Sj?gren's syndrome. Gram-positive bacterial isolates were the most common cause of infection, and accounted for almost all cases in patients with Sj?gren's syndrome. Trichiasis (cicatricial pemphigoid), topical corticosteroids, bandage contact lenses, and corneal surgery were the main predisposing factors in the development of the corneal infection. In patients with ocular cicatricial pemphigoid, infection was much less common after chemotherapeutic control had been achieved. Recurrent infections were relatively frequent. There was a high rate of major complications, particularly in microbial keratitis complicating Sj?gren's syndrome.     

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.     

Light adaptation and the luminance-response function of the cone electroretinogram

Corneal graft survival in 13 patients (14 eyes) receiving oral acyclovir following corneal transplantation for herpes simplex keratitis was compared to that in nine patients (9 eyes) who underwent penetrating keratoplasty for herpes simplex keratitis without receiving postoperative acyclovir. Mean age, duration of disease, and time of follow-up did not differ in the two groups. There were no recurrences of herpes simplex keratitis in any patient receiving acyclovir during a mean follow-up of 16.5 months compared to a 44% (4/9) recurrence rate in patients without acyclovir during a mean follow-up of 20.6 months (p < 0.01). Graft failure occurred in 14% (2/14) of acyclovir treatment eyes and in 56% (5/9) of the grafts in patients not receiving acyclovir. Long term prophylactic oral acyclovir significantly decreased the recurrence of herpes simplex keratitis and reduced corneal graft failure in patients with a history of recurrent herpes simplex keratitis who underwent corneal transplantation.Abbreviations ACV acyclovir - HSK herpes simplex keratitis - PK penetrating keratoplasty Presented as a paper at The American Academy of Ophthalmology, annual meeting in Anaheim, California 13–17 October 1991.     

马来西亚大学医学中心角膜溃疡的回顾分析

目的：分析角膜溃疡的病例分布、危险因素、临床特点、微生物检查及预后结果。方法：对2003-07／2006-04就诊于马来西亚大学医学中心的84例（87眼）患者进行研究，其中1例双眼发病，另1例曾因疱疹性角膜炎复发3次就诊。选入标准包括角膜上皮缺损、角膜基质浸润及炎症。结果：患者84例中有男46例，女38例。主要是马来人（52％）。3个主要的危险因素是角膜接触镜的配戴（47％），眼外伤（25％）及眼表疾病（24％）。在老年患者中，糖尿病（8％）及高血压（9％）是重要的系统性疾病。阳性为25％，而微生物培养阳性为73％。在各危险因素组中，绿脓杆菌是最常见的致病菌，在角膜接触镜配戴者中最高。耐庆大霉素革兰染色阴性菌有2例，耐青霉素表皮葡萄球菌有1例。75％的患者溃疡愈合，遗留角膜混浊。2mo后，54％的患眼最佳矫正视力〉6／18，14％〈3／60。3例患者需要行眼球摘除或剜除术。结论：角膜接触镜配戴和眼外伤是青年人群中主要的可预防性危险因素，相反，眼疾是老年人中不可预防的危险因素。超过60％的培养阳性病例为革兰染色阴性菌。     

单纯疱疹病毒性角膜炎的发病机制

单纯疱疹病毒性角膜炎(herpes simplex keratitis,HSK)是一种常见的眼部疾病,由单纯疱疹病毒(herpes simplex virus,HSV)感染引起。人群中超过90%的人曾经感染过HSV。HSV可以在神经组织及角膜组织长期潜伏。在适宜的刺激下,如紫外线照射、发热、精神压力、高温、低温、手术等,病毒活化增殖导致HSK。HSV感染引起的免疫反应是造成角膜组织损害的主要机制。HSK的免疫反应主要是由CD4+细胞介导的,而CD8+细胞对病毒感染具有保护作用。     

Contact lens-related microbial keratitis: how have epidemiology and genetics helped us with pathogenesis and prophylaxis

Contact lens wear is a common predisposing factor in microbial keratitis and is one of the two preventable risk factors for corneal infection in a working age population. Our understanding of the prevention and prophylaxis of contact lens-related corneal infection is informed by recent epidemiological studies describing the incidence of and risk factors for the disease, the effect of causative organism on disease severity, and an appreciation of individual immune profiles in susceptibility to and severity of the disease. Although contemporary contact lenses have not reduced the overall incidence of keratitis, a reduction in morbidity may be achievable through recognition of appropriate risk factors in severe disease, including avoiding delays in presenting for appropriate treatment, and attention to storage case hygiene practise. Severe keratitis is most commonly associated with an environmental causative organism, and daily disposable lenses are associated with less severe disease. Pseudomonas aeruginosa remains the commonest cause of contact lens-related corneal infection probably because of its unique virulence characteristics and ability to survive in the contact lens/storage case/ocular environment. In two recent outbreaks of contact lens-related infections, there has been a strong association demonstrated with particular contact lens solutions. Since the recall of these specific contact lens solutions, the rate of Acanthamoeba keratitis has remained above the expected baseline, indicating unidentified risk factors that may include environmental exposures. Individual differences in susceptibility to microbial keratitis may be partly explained by differences in single-nucleotide polymorphisms in certain cytokine genes, particularly those with a proven protective role in corneal infection.     

Corneal ulceration in the elderly in Hyderabad, south India

AIMS: To report demographic, microbiological, therapeutic, anatomical, and visual results of corneal ulceration in the elderly patients seen at a tertiary eye care centre in south India. METHODS: 102 consecutive cases of microbial keratitis in patients 65 years and older were studied. Inclusion criteria were: (i) presence of corneal stromal infiltrate upon slit lamp examination; and (ii) microbiological evaluation of corneal scrapings for suspected microbial keratitis. RESULTS: The principal predisposing factors identified in this study were ocular disease (38.2%), previous ocular surgery in the same eye (29.4%), trauma (17.6%), and severe systemic disease (16.7%). Contact lens wear was associated with only two cases (2.0%). 99 organisms were isolated in cultures of corneal scrapings from 74 (72.5%) of the 102 cases. Staphylococcus epidermidis (31.1%), filamentous fungi (25.7%), and Streptococcus pneumoniae (13.5%) were the most common isolates. 12 eyes (11.8%) required surgery, 15 (14.7%) eventually required evisceration, and nine (9.6%) of the 94 followed patients achieved an unaided vision of 20/60 or better at last follow up. CONCLUSIONS: This work represents the largest recent single centre study on (non-viral) microbial keratitis in the elderly, its management, and outcomes of therapy. While the predisposing factors differ from those of general population, the spectrum of microbes responsible for keratitis in the elderly appears to reflect the local microbial flora rather than a predilection for elderly patients. Delay in diagnosis and systemic conditions associated with advancing age probably contribute to poorer outcome from therapeutic measures.     

二次穿透性角膜移植术后失败原因分析

目的探讨二次穿透性角膜移植术（PKP）术后失败的原发病因及直接原因。方法回顾性病例研究。选择2003年1月至2010年1月于山东省眼科研究所青岛眼科医院行二次PKP患者的临床资料100例（100只眼）,统计分析失败患者的原发病因及直接原因。结果本文中行二次PKP术后病例共计100例,其中失败病例37例,失败率为37%。不同原发病因行二次PKP术后失败的数量依次为：化脓性角膜炎（11只眼,29%）、眼外伤（10只眼,27%）、单纯疱疹病毒性角膜炎（7只眼,19%）、蚕食性角膜溃疡（5只眼,14%）、大泡性角膜病变（2只眼,5%）、角膜变性及营养不良（1只眼,3%）、角膜白斑（1只眼,3%）。引起二次PKP术后失败的直接原因依次为：植片免疫排斥（17只眼,45%）、角膜内皮细胞功能失代偿（8只眼,22%）、角膜植片溃疡（7只眼,19%）、原发病复发（4只眼,11%）、角膜植片溶解（1只眼,3%）。结论二次PKP术后失败的原发病因以化脓性角膜炎为主,直接原因主要是免疫排斥。     

Risk factors for perforation in microbial corneal ulcers in north India

AIM: To identify predisposing factors leading to corneal perforation in patients with microbial keratitis. METHOD: Two groups of 60 patients each, with perforated corneal ulcers and healed/healing corneal ulcers, respectively, were recruited in a case-control study conducted in northern India. The cases and controls were matched by age and time of presentation. A standardised proforma was used to identify potential predisposing factors for demographic, social, medical, ocular, and treatment history. All participants underwent a detailed ocular examination. Corneal scrapings were performed where relevant. RESULTS: The characteristics associated with corneal perforation in microbial keratitis were outdoor occupation (p = 0.005), illiteracy (p = 0.02), excessive alcohol use (p = 0.03), history of "something falling into eye" (p = 0.003), trauma with vegetable matter (p = 0.008), vision less than counting fingers at referral (p<0.001), central location of ulcer (p<0.001), lack of corneal vascularisation (p<0.001), delay in starting initial treatment (p<0.001), failure to start fortified antibiotics (p<0.001), and monotherapy with fluoroquinolones (p = 0.002). The lack of corneal vascularisation (OR 6.4, 95% CI 4.2 to 13.5), delay in starting initial treatment (OR 35.6, 95% CI 6.9 to 68.2), and failure to start fortified antibiotics (OR 19.9, 95% CI 2.7 to 64.7) retained significance on a logistic regression model. CONCLUSIONS: This study characterises microbial keratitis cases at increased risk of corneal perforation and reinforces the need for standardised referral and treatment protocols for patients with corneal ulcer on their first contact at primary care level in the developing world.     

穿透性角膜移植排斥反应的临床分析

目的探讨导致穿透性角膜移植术后排斥反应的高危病种及危险因素。方法对86例90眼穿透性角膜移植患者术后排斥反应发生率进行回顾性分析。结果各病种排斥反应发生率不同，角膜溃疡为42．86％(9／21)；粘连性角膜白斑为39．13％(9／23)；单纯性角膜白斑为28．57％(8／28)；角膜变性或营养不良为11．11％(1／9)；先天性角膜白斑为100．00％(1／1)；圆锥角膜5眼及大泡性角膜病变3眼无排斥反应发生。术前角膜新生血管形成、虹膜前粘连、术前高眼压、术后高眼压、无晶状体状态、术式增多、大植片使排斥反应发生率增高。结论高危病种有角膜溃疡、粘连性角膜白斑、单疱病毒性角膜炎及化学伤导致的单纯性角膜白斑。术前角膜新生血管形成，虹膜前粘连，术前、术后高眼压，无晶状体，多术式联合，大植片是排斥反应发生的危险因素。     

Management of descemetocele: Our experience and a simplified treatment algorithm

Purpose:To formulate a treatment algorithm for the management of descemetocele.Methods:This was a prospective interventional study that was conducted at a tertiary eye-care center. All consecutive cases of descemetocele during the study period (April 1, 2017–March 31, 2018) were evaluated for the following parameters: age, sex, previous medical or surgical therapy, risk factors, preexisting ocular diseases, location, site and size of descemetocele, interventions undertaken, visual acuity, and the fellow eye status. The surgical modalities and fellow eye status were correlated individually with therapeutic and functional outcomes, based on which a treatment algorithm was formulated.Results:The study included 24 eyes of 24 patients (19M, 5F) with a median age of presentation of 45 years. The mean follow-up duration was 6.79 ± 3.97 months (3–12 months). The most common cause of descemetocele was microbial keratitis (66.66%), and most cases were central (50%), small (58.33%), and non-perforated (79.16%). The surgical interventions undertaken were cyanoacrylate glue (CG, 37.5%), penetrating keratoplasty (PKP, 33.33%), patch graft (16.66%), and deep anterior lamellar keratoplasty (DALK, 12.5%). Therapeutic success was noted in 13/24 eyes (54.16%). Final visual acuity > 3/60 was seen in 25% cases. Suboptimal therapeutic (P = 0.07) and visual (P = 0.34) outcomes were noted in subjects with non-functional fellow eye.Conclusion:PKP was preferred for descemetoceles with active microbial keratitis and extensive infiltrates, while CG and DALK were undertaken for healed microbial keratitis, neurotrophic keratitis, and ocular surface disorders with partial limbal stem cell deficiency (LSCD). For total LSCD, amniotic membrane graft was preferred.     

Six-year review of Acanthamoeba keratitis in New South Wales, Australia: 1997-2002

AIM: To assess the incidence and risk factors for Acanthamoeba keratitis (AK), the diagnostic interval, and the efficacy and outcome of current treatment among the population of New South Wales, Australia. METHODS: A retrospective review was carried out of all cases of AK treated at the Sydney Eye Hospital between January 1997 and December 2002. RESULTS: Twenty patients were identified with a mean follow up of 24.8 +/- 21.5 months. Acanthamoeba keratitis constitutes 4.7% of severe infective keratitis treated at Sydney Eye Hospital. The mean interval from first presentation to diagnosis was 26.6 +/- 35.1 days overall; 17.2 +/- 33.1 days for those presenting directly to our unit (69% being diagnosed within 72 h of presentation), and 44.1 +/- 34.0 days for those first presenting elsewhere. Of those with a diagnostic delay >1 month, 57% had been mistakenly diagnosed with Herpes simplex keratitis. Sixteen (80%) wore contact lenses, and eight (40%) had additional risk factors including poor lens hygiene. Complications occurred in 16 (80%), with seven (35%) requiring surgical intervention. Visual acuity improved in 18 (90%), worsened in two patients (10%), and 75% achieved 6/12 or better at last follow up. CONCLUSIONS: Acanthamoeba keratitis is a rare infection, and contact lens wear remains the commonest association, with poor hygiene constituting significant additional risk. The visual outcome has improved with the availability of effective amoebicidal agents, but patients with a diagnostic delay and non-contact lens wearers are at increased risk of recurrent disease. A high index of clinical suspicion remains the most effective strategy in implementing early treatment, and enabling a favourable outcome.     

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.