Acanthamoeba keratitis (AK) is a serious, potentially sight-threatening corneal infection caused by a pathogenic free-living amoeba. Contact lens wear is the major risk factor in its etiology. This article will review previous studies on the parasitology, epidemiology, pathogenesis, clinical presentations, diagnosis and therapeutic options. This article review previous studies up to 2004 indexed in Medline with the key words: "acanthamoeba" and "keratitis", Articles with original, clinical, evidence-based and remarkable findings were selected. Data from about 30 articles were extracted. The first cases of AK were reported more than 30 years ago. Its incidence has gradually increased due to the widespread use of contact lenses. Different approaches have been developed to improve diagnosis. Various medications including aromatic diamidines, cationic antiseptics, aminoglycosides, and imidazole derivatives have been proposed for treatment of AK. The medical treatment protocol at Labbafmejad Center, is also introduced. Finally, different surgical modalities which should be considered in case of medically non-responsive AK are discussed. These include epithelial debridement, cryotherapy, lamellar keratectomy and finally penetrating keratoplasty. Although treatment of AK is difficult and time-consuming, early diagnosis and initiation of proper management has a vital role in final visual prognosis and globe integrity.

Acanthamoeba species are vision-threatening agents by causing cornea infections known as Acanthamoeba keratitis. A 5 year-old kid with the complaints of erythema, eyelid edema, inflammation, limitation of eye movements in the right eye, and having no history of wearing contact lenses or trauma, was diagnosed of Acanthamoeba conjunctivitis through laboratory examinations in the Ophthalmology clinic. The visual sharpness of the patient improved after the treatment. A 44 year-old female patient suffering from pain, stinging, irritation, and inability to see in the left eye with the history of wearing contact lenses or trauma was diagnosed of Acanthamoeba keratitis through laboratory examinations. The agent was isolated and identified as "A. castellani" in the Genotype "T2". Examination of the left eye on the 15th day of treatment indicated that all complaints disappeared except for the cataract originated visual loss. However, the first diagnosis of Acanthamoeba keratitis appeared in the literature on a case with no history of wearing contact lenses and trauma it is found to be attention grabbing. We think that Acanthamoeba should not be ignored among microbial agents that cause eye infection with or without trauma and contact lens usage history.

Acanthamoeba keratitis is a vision-threatening infection caused by pathogenic species of the genus Acanthamoeba. In this study, 13 Acanthamoeba keratitis cases were diagnosed among 52 keratitis patients. To confirm the identity of Acanthamoeba at the genus level, a PCR-based method was used, and their pathogenic potential was determined using in vitro cytotoxicity assays on human corneal epithelial cells. Twelve (92.3%) of Acanthamoeba keratitis patients were contact lens wearers; among them eleven (91.7%) wore soft contact lenses. 11/13 (84.6%) isolates were axenised in liquid culture medium, of which 10 (90.9%) isolates disrupted corneal cells. Nine (69.2%) isolates showed Acanthamoeba sp. group II, and four (30.8%) showed group III morphology. To our knowledge this is the first report of determination of Acanthamoeba pathogenicity in Iran. This study confirms the importance of determination of pathogenic potential of Acanthamoeba isolates for clinical purposes.

Acanthamoeba keratitis is a vision - threatening infection and the most important risk factors are contact lenses Characteristic symptoms include disproportionately severe ocular pain, epithelial ulcer, ring stromal infiltrate and resistance to antimicrobial treatment. The aim is to report the first cases of Acanthamoeba keratitis in Yazd in a retrospective study confirmed on histopathological and confocal microscopy. All of our patients used soft contact lenses and were women. The age range was between 20-29 years. One eye was misdiagnosed as herpes simplex keratitis and two were misdiagnosed as bacterial keratitis. A delayed visit as well as a late diagnosis led to the advanced stage of eye disease. Improvement in visual acuity following medical therapy was seen in two patients and one patient needed urgent keratoplasty for corneal necrosis. A prompt clinical and laboratory diagnosis along with treatment with propamidine- isentionate resulted in significant improvement of eye condition Failure to disinfect contact lenses and introduction of tap water rinsing of storage cases were associated with increased risk of Acanthamoeba infection. Penetrating keratoplasty is an effective treatment for medically unresponsive acanthamoeba keratitis. Confocal microscopy is the most effective and a fast diagnostic tool because it ensures the detection of acanthamebic cysts and trophozoids in corneal stroma.

Purpose: To report an atypical case of acanthamoeba keratitis. Patients &Methods: A 19-year-old girl presented with a history of recurrent herpetic keratitis and a history of short-time contact lens wear. Laboratory work-up for herpetic, bacterial, and acanthamoeba sources were negative and the patient failied to follow up. On later presentation she had corneal necrotizing stromal ulcer needed penetrating keratoplasty. Histological examination revealed acanthamoeba cysts. Conclusion: When bacterial cultures are negative other infectious agent should be suspected. If clinical and laboratory work-up confirms the diagnosis of herpetic keratitis but antiviral treatment fails, a possible mixed infection should be looked for. If our work-up is negative, due to lower sensitivity of acanthamoeba culture, acanthamoeba should be suspected and evaluated with proper methods such as polymerase chain reaction.

Back Ground and Purpose: Some Acanthamoeba species can cause a chronic, progressive ulcerative keratitis, not responsive to antimicrobial therapy and frequently mistaken as stromal herpetic keratitis. In Acanthamoeba keratrtis (AK) many patients are initially treated with inappropriate drug therapies, hence, early detection of Acanthamoeba infection is critical. Contrary to molecular methods, use of parasite culturing as a diagnostic method may take several weeks. In the present work, PCR was used for diagnosing AK. Materials and Methods: Corneal scraping specimens were collected from 70 patients referred to Farabi hospital as well as private clinics in Tehran. The specimens were cultured in ECNNA then the growing parasites were harvested. Phenol-chloroform method was applied for DNA extraction directly on corneal scraping specimens. Polymerase Chain Reaction was done for 18s rDNA amplification of the parasite using JDP1 and JDP2 as specific primers.Results and Conclusion: Following PCR amplification of 18s rDNA of 70 specimens, 21 detected positive and a single band (458 bp) appeared on gel agarose and only 21 of the specimens (the same samples) grew in ECNNA culture after a long time. Therefore, PCR is fast and highly efficient in the diagnosis of Acanthamoeba keratitis.