title: Painless Acanthamoeba Keratitis with Normal Vision.
abstract: To report an atypical case of contact lens-related Acanthamoeba keratitis.
  
  
  
  A 15-year-old secondary school female student with a history of soft contact lens wear was referred to our hospital by a private general practitioner for management of right eye redness and discomfort for 2 weeks. Upon examination, the best-corrected visual acuity was 20/20 and 20/16 for her right and left eyes, respectively. There was diffuse radial keratoneuritis noted in the cornea of her right eye without any associated epithelial defect. Corneal scraping was performed to induce epithelial defect over the keratoneuritis area, and it was positive for Acanthamoeba trophozoites. She was treated with amoebicidal therapy consisting of propamidine isethionate 0.1% and polyhexamethylene biguanide 0.02%, for 6 months. The patient did not complain of any ocular pain in the entire course of her disease. She attained a final visual acuity of 20/13 in the affected eye with residual peripheral radial perineuritic scar.
  
  
  
  Atypical presentation of Acanthamoeba infection is uncommon. This case should arouse the awareness of an indolent presentation of this potentially sight-threatening disease. Clinicians should have a high level of suspicion in contact lens users who present with corneal abnormalities despite an absence of pain. Microbiological work-up and prompt treatment led to a complete resolution of Acanthamoeba infection in our patient.
authors.affiliation: *MRCSEd(Ophth), MBBS †MD ‡FRCS, MMedSc(Hons) Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital and Alice Ho Miu Ling Nethersole Hospital, Shatin, New Territory, Hong Kong, SAR (PWRK, KWK, VJ, ALY); and Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong, SAR (VJ, ALY).
authors.forename: Pui Wai Rachel
authors.initials: PW
authors.lastname: Kwok
authors.forename: Ka Wai
authors.initials: KW
authors.lastname: Kam
authors.forename: Vishal
authors.initials: V
authors.lastname: Jhanji
authors.forename: Alvin L
authors.initials: AL
authors.lastname: Young
mesh_terms: D000048:Acanthamoeba; D015823:Acanthamoeba Keratitis / Q000175:diagnosis / Q000188:drug therapy / Q000469:parasitology*; D000293:Adolescent; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D001550:Benzamidines / Q000627:therapeutic use; D001645:Biguanides / Q000627:therapeutic use; D003263:Contact Lenses, Hydrophilic / Q000469:parasitology*; D003315:Cornea / Q000469:parasitology; D004202:Disinfectants / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D058447:Eye Pain / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D005260:Female; D006801:Humans; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D000981:Antiprotozoal Agents; D001550:Benzamidines; D001645:Biguanides; D004202:Disinfectants; C031233:polihexanide; C046651:propamidine isethionate