Microbial keratitis in orthokeratology: the Australian experience

Background: This study was conducted to investigate the demographics of orthokeratology (OK) practice in Australia, to uncover any previously undocumented cases of serious adverse responses in OK, including microbial keratitis (MK), and to review the demographics of MK in OK in Australia. Methods: A questionnaire was sent to the 62 members of the Orthokeratology Society of Australia (OSA). Questions related to aspects of their OK practice, demographics of their OK patient base and any adverse responses to OK lens wear that they had encountered. Results: Thirty‐three questionnaires (53 per cent) were returned. OSA members have been fitting OK lenses for a median of 7.5 years. OK patients were predominantly female, Caucasian, aged between 15 and 39 years and wearing lenses in an overnight modality. In addition to two cases reported previously, the survey uncovered seven further cases of MK in OK patients over an eight‐year period. The infecting organism was Pseudomonas aeruginosa in four cases, Acanthamoeba spp. in two cases and unknown in three cases. There was no loss of visual acuity in seven cases. One case resulted in vision of counting fingers at one metre and another case resolved with 6/12 visual acuity. Non‐compliance with instructions on lens care and after‐care was reported in seven of nine cases of MK. Conclusion: Overall, OSA members who responded to the survey have many years of experience in OK. The typical Australian OK patient is in young adulthood, female and Caucasian. A total of nine cases of presumed MK associated with OK have been reported in Australia over an eight‐year period and seven of these were new cases uncovered by this survey. Our analysis suggests that the demographics of MK cases in OK reflect the demographics of the OK lens‐wearing population.     

Infectious keratitis related to orthokeratology

PURPOSE: To report 28 cases of infectious keratitis related to orthokeratology lens overnight wear in China. METHODS: From March 2000 to August 2001, 28 cases of infectious keratitis related to overnight orthokeratology lens wear were diagnosed in Beijing Institute of Ophthalmology. These were retrospectively reviewed with regard to the pathogens isolated, duration of wear, the time since onset of symptoms, and age. Cultures of corneal scrapes for bacteria, fungus and Acanthamoeba were performed in all of the 28 cases. RESULTS: All cases were students, including 10 males and 18 females, average age was 16 years (range 10-21 years). The duration of orthokeratology overnight wearing was from 2 weeks to 2 years. Uncorrected visual acuity (UCVA) on initial examination in our institute was from 20/200 to light perception. Of 28 isolates, 24 were culture positive (including 11 bacteria, 11 Acanthamoeba and two fungi), and four were culture negative. In two of the four culture negative cases, Acanthamoeba cysts were detected in the corneal stroma with the confocal microscope. Acanthamoeba and Pseudomonas aeruginosa accounted for 75% (21 of 28) of the cases of infectious keratitis. CONCLUSION: Infectious keratitis is a severe complication associated with overnight orthokeratology lens wear. Ophthalmologists should pay more attention to this complication in practice.     

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

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

Acanthamoeba keratitis cluster: an increase in Acanthamoeba keratitis in Australia

Background:  This study was undertaken in response to an increase in the number of patients treated for Acanthamoeba keratitis at a tertiary referral hospital in Brisbane, Australia. Incidence and patient characteristics were investigated over a 4-year period.
Methods:  A retrospective consecutive case series study was performed on patients with Acanthamoeba keratitis presenting to the Princess Alexandra Hospital between January 2003 and March 2007.
Results:  Nine cases of Acanthamoeba keratitis were identified over 12 months from March 2006 to March 2007 compared with four cases over the previous 37 months from January 2003 to February 2006. This was an increase from 0.07 cases per 1000 outpatient visits to 0.42 per 1000 ( P  = 0.003). Of the 13 cases, 11 patients used soft contact lenses of which two used monthly extended overnight wear silicone hydrogel lenses. Of the five patients who specified the type of contact lens solution they had used, three reported using AMO Complete Moistureplus Multipurpose solution, one reported using the AMO Complete Comfortplus Multipurpose solution and one was unsure which type of AMO Complete solution they were using.
Conclusions:  There has been a significant increase in incidence of cases of Acanthamoeba keratitis presenting to our institution. The type of contact lens solution and the use of silicon hydrogel lenses combined with extended overnight wear may play a role; however, the significance is unclear given the small numbers for analysis. Further study of incidence and patient characteristics is warranted to identify risk factors and causes for the rising incidence.     

Steroid sensitive Acanthamoeba keratitis

A 44-year-old woman with proven Acanthamoeba keratitis was successfully treated medically with resultant 6/9 vision. During the treatment, repeated attempts to titrate the patient off topical corticosteroids resulted in recurrent flare-up of inflammatory keratitis from which Acanthamoeba could not be recultured. It is suggested that steroid administration during the course of Acanthamoeba keratitis may need to be withdrawn extremely slowly to avoid the recurrence of what appears to be an immunological corneal reaction.     

Acanthamoeba keratitis and contact lens wear

Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens‐related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three‐year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.     

阿米巴角膜炎刮片细胞学特征

目的 探讨刮片细胞学检查诊断阿米巴角膜炎病原体形态特征.方法 实验研究.收集1991年5月至2007年12月期间,首都医科大学附属北京同仁医院、北京市眼科研究所眼微生物室诊断为阿米巴角膜炎的病例159例,对其实验室检查与临床资料进行分析.采用姬姆萨染色法和湿片检查法,对角膜刮片细胞进行观察并照相记录.结果 159例阿米巴角膜炎通过姬姆萨染色刮片细胞学检出阿米巴病原131例(82.4%),阿米巴培养阳性110例(69.2%).刮片细胞学检出率明显高于培养检出率.刮片细胞学检查可观察到典型的滋养体、包囊、包囊前期、空包囊等病原形态,对临床诊断有重要意义.刮片中水肿溶解的角膜上皮细胞、渗出细胞、丝状真菌的关节孢子或厚膜孢子、空泡、脂滴及药物结晶等需要与病原体相鉴别.通过湿片法主要观察滋养体的运动状态.结论 应用刮片细胞学检查法诊断阿米巴性角膜炎,观察到滋养体、包囊、包囊前期及空包囊典型特征对阿米巴性角膜炎有重要病原学诊断价值.     

Medical treatment for combined Fusarium and Acanthamoeba keratitis

Purpose: Acanthamoeba and fungal keratitis are rare ocular infections. We report cases of combined Fusarium and Acanthamoeba keratitis and the clinical course of medical treatment. Methods: We reviewed the medical records of patients treated for culture‐proven Acanthamoeba keratitis at a referral centre, during 2001?2006. Results: Eleven consecutive patients were treated for culture‐proven Acanthamoeba keratitis during the 5 years, two of whom had combined fungal infections. A 29‐year‐old man presented with ground‐glass corneal oedema and epitheliopathy caused by contact lens use. The other patient, a 7‐year‐old girl, had eye trauma that led to a feathery corneal infiltrate. Both cases were treated with topical 0.02% polyhexamethylene biguanide (PHMB), 0.1% propamidine, 1% clotrimazole and 5% natamycin. Therapeutic keratoplasty was not required in either case. Conclusions: Timely identification of the pathogen, with repeated culture and smear if necessary, as well as adequate dosage to prevent recurrence is highly recommended in order to preclude the need for therapeutic penetrating keratoplasty.     

Bilateral acanthamoeba keratitis and treatment strategy based on lesion depth

CASE REPORT: This report summarizes a case of bilateral acanthamoeba keratitis in an 18-year-old male contact-lens wearer. Early diagnosis is important and combination treatment is recommended, tailored to the depth of the lesions. COMMENTS: Treatment can be difficult, particularly since amoebic cysts are especially resistant. Surgery may be required for advanced cases. Suggestions for reducing corneal toxicity to antiamoebic therapy are included.     

棘阿米巴角膜炎的感染免疫及防治

棘阿米巴角膜炎是棘阿米巴属引起的角膜表面的感染。通常由粘附于软性接触镜的棘阿米巴滋养体所传递。当寄生虫粘附于角膜上皮细胞表面时可触发感染。后来的过程包括：寄生虫介导的细胞病理效应、诱导凋亡和通过产生各种蛋白酶入侵角膜基质层。滋养体也可浸润角膜神经，造成放射状角膜神经炎。棘阿米巴包囊即具有免疫原性又具有抗原性。然而，诱导针对棘阿米巴抗原的细胞介导的免疫应答对棘阿米巴角膜炎即无减轻作用又无预防效应。但是，普通粘膜免疫系统对于棘阿米巴角膜炎却具有显著的预防作用。其机制是通过IgA抗体阻断感染性滋养体与上皮层的结合。局部使用糖皮质激素对于缓解疼痛和减轻炎症反应具有显著效果，但可通过诱导静止包囊的脱包囊、增加滋养体的细胞病理效应以及麻痹初始免疫系统使疾病复燃。因此．糖皮质激素的使用是一把“双刃剑”。     

我国致病性自生生活阿米巴性角膜炎的研究进展

1992年金秀英等首次报道了我国棘阿米巴性角膜炎病例.十余年来,国内对这一致盲性角膜病的研究不断展开,研究范围涉及了病原学、生物学、虫株培养和保存方法、致病性和毒力、感染模型建立、病理学和免疫学、临床诊断及治疗等诸多方面.     

The effect of propolis in experimental Acanthamoeba keratitis

PURPOSE: To examine the effect of propolis in a rat model of Acanthamoeba keratitis and to determine its in vitro cytotoxicity in cultured corneal epithelial cells. METHODS: Eighteen Wistar albino rats were used. Cultured corneal epithelial cells obtained from two healthy rats for in vitro cytotoxicity of propolis. Corneal stromal inoculation was performed in 16 rats with amoebic culture containing 1 x 10(6) amoeba/mL. Rats with Acanthamoeba keratitis 5 days later after the inoculation were divided randomly into four groups, and eight eyes of each group were treated with study drugs. The propolis, chlorhexidine (CHX), propolis plus CHX and control eyes were treated with topical propolis, 0.002% CHX, propolis plus 0.002% CHX and lubricant eye drops, respectively. The study drugs were instilled every one hour for 10 days. All eyes were examined and keratitis graded by slit-lamp biomicroscopy on days 2, 5 and 10 during the administration of the study drugs. After the completion of keratitis grading, all the 16 rats were humanely killed and their corneas were excised and used for Acanthamoeba culture to evaluate presence of Acanthamoeba growth after treatment 14 days later. RESULTS: Concentrations of propolis higher than 7.81 mg/mL cause damage to corneal epithelial cells in the experiment of in vitro cytotoxicity of propolis on corneal epithelial cells. The keratitis grade on day 2 in the CHX eyes was significantly lower than that in the control eyes (P < 0.05). The keratitis grades on days 5 and 10 in the propolis, CHX and propolis plus CHX eyes were significantly lower compared with those on days 5 and 10 in the control eyes (P < 0.05). In the propolis eyes, the keratitis grade on day 5 was significantly lower than that on day 2 (P < 0.05), and it was significantly lower on day 10 compared with that on day 5 (P < 0.05). In the CHX and propolis plus CHX eyes, the keratitis grade on day 10 was significantly lower compared with that on days 2 and 5 (P < 0.05). In the control eyes, there was no significant difference in the keratitis grades on days 2, 5 and 10 (P > 0.05). The culture positivity at Acanthamoeba growth after treatment experiment in the propolis, CHX and propolis plus CHX eyes was significantly lower than that in the control eyes (P < 0.05). CONCLUSIONS: We suggest that propolis had amoebicidal properties in this rat model of Acanthamoeba keratitis. Further investigations to evaluate the antimicrobial activity of the individual fractions of the resin could yield more information about its mechanism of action in treating this disease.     

Coexistent adenoviral keratoconjunctivitis and Acanthamoeba keratitis

A 17-year-old youth presented with bilateral follicular conjunctivitis and nummular subepithelial corneal infiltrates. Failure of this to settle in an outpatient setting led to corneal scraping with microscopy and culturing for bacteria, fungi, Herpes simplex, adenovirus and Acanthamoeba as an inpatient. Polymerase chain reaction analysis of corneal cells was positive for adenovirus, and culture on live Escherichia coli-coated agar plates was positive for Acanthamoeba by phase contrast microscopy on day two. We conclude that Acanthomoeba infection can complicate adenoviral keratoconjunctivitis. This observation is in keeping with previously reported modes of infection by Acanthamoeba, whereby any epithelial breach seems to allow inoculation of the eye by this opportunistic organism.     

Infectious keratitis in leprosy

AIM: To describe leprosy characteristics, ocular features, and type of organisms that produce infective corneal ulcers in leprosy patients. METHOD: The records of all leprosy patients admitted for treatment of corneal ulcers between 1992 and 1997 were reviewed. RESULTS: 63 leprosy patients, 53 males and 10 females, are described. 16 were tuberculoid and 47 lepromatous. 25 patients had completed multidrug therapy. 10 patients had face patches, eight had type I reaction, and 10 had type II reaction. 43 (68%) patients had hand deformities. In 54% of patients pain was absent as a presenting symptom. 19 patients gave a history of trauma. In 15 patients ulcers had also occurred on the other eye, five of them having occurred during the study period and the rest before 1992. Of the 68 eyes with corneal ulcers, 28 had madarosis, 34 had lagophthalmos, nine had ectropion, three had trichiasis, six had blocked nasolacrimal ducts, and 39 decreased corneal sensation. In 14 eyes, a previous lagophthalmos surgery had been done. 16 patients were blind at presentation. 32% of ulcers were located centrally. After treatment only 18% of the eyes showed visual improvement. Five types of fungus were cultured, two of them rare ocular pathogens. CONCLUSIONS: Corneal ulcers occur more in males and in the lepromatous group of patients. Decreased corneal sensation, lagophthalmos and hand deformity are closely associated. Indigenous treatment and late presentations were notable in many patients. Visual outcome is not good. There is increased risk of developing an ulcer in the other eye. Fungal corneal ulcers are not uncommon.     

穿透性角膜移植治疗棘阿米巴角膜炎的临床研究

目的　探讨术前诊断和围手术期药物治疗等因素对穿透性角膜移植治疗严重棘阿米巴角膜炎术后复发的影响。方法　对 1996～ 2 0 0 2年诊治的 18例棘阿米巴角膜炎患者进行临床分析 ,术前确诊 12例 ,误诊 6例 ,角膜感染直径均大于 7mm。治疗过程中 18例患者均因病情加重而行穿透性角膜移植术 (PKP)。术后依据术前诊断 ,确诊者继续给予抗阿米巴药物治疗 ,而误诊者继续术前的抗病毒、真菌及细菌治疗。 7例患者 (确诊 2例 ,误诊为病毒性角膜炎 3例 ,细菌性角膜炎 2例 )在术后早期接受全身和局部的糖皮质类激素药物治疗。对诊断的准确性和术后早期持续使用 (>7d)糖皮质激素两个因素与术后复发情况进行病例 对照研究 ,计算其比数比。结果　随访时间平均 10个月 ,13例 (72 % )患者未见复发 ,其中术前确诊 11例 ,误诊 2例 ;5例 (2 8% )患者术后复发。 7例患者术后接受了持续糖皮质激素治疗 ,其中 4例复发。计算误诊和术后早期持续使用糖皮质激素两种影响因素对复发的影响的比数比分别为 2 2 (P =0 0 2 1)和 13(P =0 0 4 7)。结论　PKP是治疗药物不能控制的严重棘阿米巴角膜炎的有效方法。术前明确诊断、围手术期抗阿米巴治疗及早期避免持续使用糖皮质激素可降低棘阿米巴角膜炎术后的复发率。 (中华眼科杂志 ,2 0     

棘阿米巴性角膜炎误诊病例的回顾性研究

目的：回顾性分析棘阿米巴性角膜炎的临床特点及其误诊原因,方法：对269例临床诊断为单纯疱疹性角膜炎,细菌性角膜炎及不明原因感染性角膜炎患者的穿透性角膜移植术后组织理切片标本进行回顾性研究,寻找漏诊的棘阿米巴性角膜炎病例,并根据其临床资料,组织病理图特点进行分析。结果：重新复查的病理切片中,发现漏诊棘阿米巴性角膜炎5例,误诊单纯疱疹性角膜炎3例,真菌性角膜炎及化脓性角膜炎各1例,棘阿米巴角膜炎的主要症状为角膜基质内环状浸润及放射性神经痛,5例曾行穿透性角膜移植术治疗,其中2例复发后再次行穿透性角膜移植术仍未能控制感染,最终摘除眼球,结论：棘阿米巴性角膜炎仍是我国角膜病致盲的主要原因,确诊后即应采取积极治疗措施。     

共焦显微镜在棘阿米巴性角膜炎临床诊断中的应用

目的 :评价共焦显微镜 (confocalmicroscopy)在棘阿米巴性角膜炎 (acanthamoebakeratitis)临床诊断 ,尤其是早期诊断中的应用价值。方法 :对临床拟诊为棘阿米巴性角膜炎患者 2 3例进行共焦显微镜检查 ,并同时行角膜涂片及棘阿米巴原虫培养检查 ,对两种检查方法的结果进行比较。结果 :2 3例患者中 ,13例共焦显微镜检查可见棘阿米巴包囊和 /或神经炎表现 ,综合各项检查结果及临床表现 ,18例确诊为棘阿米巴性角膜炎 ,共焦显微镜的阳性率为 5 6 5 %。在 5例表现为上皮性及浅基质病变的早期角膜炎患者 ,共焦显微镜检查 3例 (6 0 % )为阳性 ,刮片、培养各 1例 (2 0 % )为阳性。结论 :共焦显微镜检查是一种无创、快速和有效的活体检查手段 ,在棘阿米巴性角膜炎的诊断中 ,如同时结合实验室刮片及培养和患者临床情况可起到重要的辅助诊断作用 ,尤其是在棘阿米巴角膜炎的早期诊断中 ,可以起到更重要的作用     

Infectious keratitis related to overnight orthokeratology

PURPOSE: To report the microbial culture results, clinical course, and visual outcomes for infectious keratitis related to overnight orthokeratology. METHODS: The records of patients with infectious keratitis related to overnight orthokeratology who presented to a tertiary referral center from April 2000 to March 2003 were retrospectively reviewed. RESULTS: Twenty patients (21 eyes) were included; 1 patient had bilateral infections. The average age of the patients was 14 years. The average period between the time the patient started the overnight orthokeratology program and the onset of infectious keratitis was 23 months. Thirteen of the 21 eyes were culture positive. Organisms cultured were Pseudomonas aeruginosa (n = 9), coagulase-negative Staphylococcus species (n = 2), Serratia marcescens (n = 1), and Acathamoeba species (n = 1). All patients responded well to medical antimicrobial treatment. Final best spectacle-corrected visual acuity ranged from 20/20 to 20/100. CONCLUSIONS: Infectious keratitis is a potential complication of overnight orthokeratology that may cause significant visual impairment. Parents of children who consider overnight orthokeratology should evaluate the benefit of temporary myopia reduction and the risk of infection.     

Successful medical treatment of Acanthamoeba keratitis

Purpose: To describe the outcome of a series ofAcanthamoeba keratitis treated with a similar regimen. Methods: All cases diagnosed with Acanthamoeba keratitisin a referral centre from June 1994 through June 1997 wereincluded. Diagnosis of Acanthamoeba keratitis was based inclinical presentation and laboratory results. Positive laboratoryidentification of Acanthamoeba from corneal scraping or contactlens was required, unless the patient had very characteristicsymptoms (severe pain) and signs of the infection, includingperineural infiltrates. Initial intensive treatment includedtopical polyhexamethylene biguanide (PHMB) 0.02%, propamidineisothionate 0.1% and broad-spectrum antibiotics. The treatmentwas gradually tapered. After documented response toanti-acanthamoeba therapy, topical steroids were introduced; theywere discontinued before cessation of the anti-Acanthamoebaregimen. Results: Six males and four females, with a meanage of 30.0 ± 7.4 years were included in this study. Allcases weared contact lenses. On presentation all cases had severepain, and epitheliopathy was associated with stromal infiltratein most (seven of ten) cases. Four patients had anterior uveitis.Perineural infiltrates were present in three cases and ringinfiltrate in one patient. Anti-amoebic treatment was started12.7 ± 7.2 days after beginning of symptoms. The clinicalresponse to therapy was very satisfactory in all patients. Withintwo to three weeks all patients had remarkable lessening of painand photophobia, and improvement of clinical signs. At two tothree months, visual acuity had improved in all patients. Twopatients required penetrating keratoplasty for visualrehabilitation. Conclusion: The use of PHMB and propamidinecured all cases of Acanthamoeba keratitis. Cautious introductionof steroids was associated with expedited resolution ofinflammation and provided symptomatic relief.