Bharathi Jayahar M, Srinivasan M, Ramakrishnan R, Meenakshi R, Padmavathy S, Lalitha Prajna N
Microbiology Research Centre, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Tirunelveli, Tamil Nadu-627 001, India.
Indian J Ophthalmol. 2007 Jan-Feb;55(1):37-42. doi: 10.4103/0301-4738.29493.
To determine the epidemiological and clinical characteristics of Acanthamoeba keratitis and also to determine the sensitivity and specificity of smears in the detection of Acanthamoeba.
A retrospective review of all culture-positive cases of Acanthamoeba keratitis seen between October 1999 and August 2002 was performed. Corneal scrapes were subjected to culture and microscopy using standard protocols.
Out of 3183 consecutive patients with clinically diagnosed corneal ulcers evaluated, 33 (1.04%) were found to be due to Acanthamoeba. Twenty-four out of 33 (72.72%) were less than 51 years of age (P<0.001). All patients were from rural areas (P<0.001) and 26 (78.79%) of them were agricultural workers (P=0.031). All 33 had history of corneal injury (P<0.001) and 28 (84.85%) patients had injury with mud (P<0.001). All 33 (100%) patients had previous medical treatment (P=0.009) and 10 (30.3%) had used traditional eye medicines (P=0.183). A clinical pattern of ring infiltrate was characteristic in 15 (45.45%) patients. The diameter of the corneal ulcer was more than 6 mm in 27 (81.82%) eyes (P<0.001). Twenty-six (78.79%) patients had visual acuity of perception of light on initial presentation (P<0.001) and 24 (72.73%) had the same as their final visual outcome. The sensitivity of 10% potassium hydroxide (KOH) preparation was found to be higher (P<0.001) in the detection of Acanthamoeba cysts.
The incidence of Acanthamoeba keratitis amongst the corneal ulcer patients was 1% in this setting and it was mainly due to corneal injury by mud. The KOH preparation is a sensitive diagnostic tool for the detection of Acanthamoeba. Delayed diagnosis or misdiagnosis and inappropriate antimicrobial therapy results in poor visual outcome.
确定棘阿米巴角膜炎的流行病学和临床特征,并确定涂片检测棘阿米巴的敏感性和特异性。
对1999年10月至2002年8月间所有培养阳性的棘阿米巴角膜炎病例进行回顾性研究。角膜刮片按照标准方案进行培养和显微镜检查。
在连续评估的3183例临床诊断为角膜溃疡的患者中,33例(1.04%)被发现是由棘阿米巴引起的。33例中有24例(72.72%)年龄小于51岁(P<0.001)。所有患者均来自农村地区(P<0.001),其中26例(78.79%)为农业工人(P=0.031)。所有33例均有角膜损伤史(P<0.001),28例(84.85%)患者有泥土致伤史(P<0.001)。所有33例(100%)患者曾接受过治疗(P=0.009),10例(30.3%)使用过传统眼药(P=0.183)。15例(45.45%)患者具有环形浸润的临床特征。27只眼(81.82%)角膜溃疡直径大于6mm(P<0.001)。26例(78.79%)患者初诊时视力为光感(P<0.001),24例(72.73%)患者最终视力与初诊时相同。发现10%氢氧化钾(KOH)制剂在检测棘阿米巴包囊方面敏感性更高(P<0.001)。
在此环境下,角膜溃疡患者中棘阿米巴角膜炎的发病率为1%,主要是由泥土导致的角膜损伤引起。KOH制剂是检测棘阿米巴的敏感诊断工具。诊断延迟或误诊以及不适当的抗菌治疗会导致视力预后不良。