title: Microcyst response to high Dk/t silicone hydrogel contact lenses.
abstract: OBJECTIVE
  To investigate the microcyst response to extended wear (EW) with high oxygen transmissible (Dk/t) silicone hydrogel lenses.
  
  
  METHODS
  Microcysts were monitored for 12 months in subjects wearing low Dk/t hydrogel lenses on a 6-night EW schedule or high Dk/t hydrogel lenses on a 30-night EW schedule. Subjects wearing low Dk/t lenses transferred to the high Dk/t EW lenses and schedule after 12 months and were monitored for a further 6 months.
  
  
  RESULTS
  The mean number of microcysts did not deviate from baseline in the high Dk/t group. Microcysts in the low Dk/t group increased over 12 months, and more microcysts were observed in low Dk/t lens wearers compared with high Dk/t lens wearers after 3 months. Microcysts increased in 50% of subjects 1 week after transfer to high Dk/t lenses and returned to baseline levels seen with high Dk/t lens wear within 3 months.
  
  
  CONCLUSIONS
  EW with high Dk/t silicone hydrogel lenses did not cause an increase in microcyst numbers. It is not necessary to discontinue lens wear with patients who transfer from low to high Dk/t lenses because the increase in microcysts is transitory. This result has implications for practitioners when fitting and assessing the success of high Dk/t hydrogel lenses.
authors.affiliation: Cornea and Contact Lens Research Unit, School of Optometry and Cooperative Research Centre for Eye Research and Technology, The University of New South Wales, Sydney, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Keay
authors.forename: D F
authors.initials: DF
authors.lastname: Sweeney
authors.forename: I
authors.initials: I
authors.lastname: Jalbert
authors.forename: C
authors.initials: C
authors.lastname: Skotnitsky
authors.forename: B A
authors.initials: BA
authors.lastname: Holden
mesh_terms: D000328:Adult; D001315:Australia; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003316:Corneal Diseases / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D003560:Cysts / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D004867:Equipment Design; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000009:adverse effects*; D015994:Incidence; D008297:Male; D010100:Oxygen; D010539:Permeability; D013997:Time Factors
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D010100:Oxygen