title: Trends in microbial keratitis associated with orthokeratology.
abstract: OBJECTIVE
  Orthokeratology is a clinical technique that uses reverse-geometry rigid gas-permeable contact lenses to alter corneal shape to provide temporary reduction of refractive error. Microbial keratitis is the most severe, potentially vision-threatening adverse response associated with orthokeratology contact lens wear. This article aims to review all reported cases of confirmed and presumed microbial keratitis associated with orthokeratology and to examine trends in microbial keratitis in orthokeratology over time.
  
  
  METHODS
  Cases of microbial keratitis associated with orthokeratology were identified from case reports published in the optometric, ophthalmologic, and vision science literature and published in abstract form for papers or posters presented at optometric or ophthalmologic conferences.
  
  
  RESULTS
  A total of 123 cases of microbial keratitis associated with orthokeratology have been reported since 2001, dating back to 1997. Most patients were female, East Asian, and aged between 8 and 15 years. The infectious organism was implicated as Pseudomonas aeruginosa for 46 (38%) of these cases and as Acanthamoeba species for 41 (33%) cases. The peak year for occurrence of microbial keratitis was 2001 and accounted for more than half (64 [52%] of 123) of all reported cases. All cases in this year were reported from East Asia, including China (47 cases), Taiwan (11 cases), and Hong Kong (6 cases).
  
  
  CONCLUSIONS
  Although there has been an increasing number of reports of microbial keratitis associated with orthokeratology since 2001, most (85 [69%] of 123) of these cases occurred in East Asia, particularly in China and Taiwan, during a relatively short period, when regulation of this modality was limited. The high prevalence of cases of Acanthamoeba keratitis reported with this modality emphasizes the importance of eliminating the use of tap water in care regimens for overnight orthokeratology.
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
authors.forename: Kathleen G
authors.initials: KG
authors.lastname: Watt
authors.forename: Helen A
authors.initials: HA
authors.lastname: Swarbrick
mesh_terms: D015823:Acanthamoeba Keratitis / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002681:China / Q000453:epidemiology; D004813:Epidemiology / Q000639:trends; D015818:Eye Infections, Bacterial / Q000209:etiology*; D015821:Eye Infections, Fungal / Q000209:etiology*; D015822:Eye Infections, Parasitic / Q000209:etiology*; D005202:Asia, Eastern / Q000453:epidemiology; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007634:Keratitis / Q000453:epidemiology* / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D054158:Orthokeratologic Procedures / Q000009:adverse effects*; D015995:Prevalence; D011552:Pseudomonas Infections / Q000453:epidemiology; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology