title: Clinical characterization of spherical post-lens debris associated with lotrafilcon high-Dk silicone lenses.
abstract: OBJECTIVE
  Experience with high Dk silicone hydrogel lenses has revealed post-lens debris, which is characterized by the appearance of spherical, translucent particles referred to as "mucin balls." The objectives of this analysis were to characterize the presence of mucin balls, determine whether any ocular characteristic predicts the development of mucin ball debris, and determine whether there is any association between mucin balls and the ocular response to contact lens wear.
  
  
  METHODS
  Ninety-two subjects wore lotrafilcon A lenses on an extended wear basis for up to 30 nights and were followed for 6 months. Mucin balls were graded on a 0 to 4 scale at three visits. Subjective ratings and biomicroscopic appearance were recorded at all visits.
  
  
  RESULTS
  Mucin balls were observed in 70% of subjects at one or more visits, and 29% of subjects at all three visits. There was no change in the mean grade of mucin balls over time. Mucin balls were graded > 1 in 20% of eyes, > 2 in 6% of eyes, and > 3 in 2% of eyes. Subjects who exhibited mucin balls at each clinical visit had significantly steeper keratometry readings along the flatter meridian (44.3 D) than those who never exhibited mucin balls (42.9 D, P < 0.0001). The percentage of subjects who "never" use lubricating drops was higher in the subjects with mucin balls (P = 0.0014). No association was found between mucin ball observation and biomicroscopic appearance, inflammatory responses, or subjective responses.
  
  
  CONCLUSIONS
  The presence of mucin balls does not appear to be detrimental to contact lens wear. Eyes with steeper corneal curvature were significantly more likely to present with mucin ball debris, indicating they may be a function of lens fit. Clinical factors that may be modified in order to manage the more severe presentation of mucin balls are the use of lubricating drops and the number of nights extended wear schedule.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, ON, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Dumbleton
authors.forename: L
authors.initials: L
authors.lastname: Jones
authors.forename: R
authors.initials: R
authors.lastname: Chalmers
authors.forename: D
authors.initials: D
authors.lastname: Williams-Lyn
authors.forename: D
authors.initials: D
authors.lastname: Fonn
mesh_terms: D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003315:Cornea / Q000378:metabolism*; D003316:Corneal Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D015994:Incidence; D009077:Mucins / Q000378:metabolism*; D017060:Patient Satisfaction; D011379:Prognosis; D012720:Severity of Illness Index; D012826:Silicone Elastomers
chemical_list: D009077:Mucins; D012826:Silicone Elastomers