title: Contact lens-induced circumlimbal staining in silicone hydrogel contact lenses worn on a daily wear basis.
abstract: OBJECTIVE
  The principal objective of the study was to measure the conjunctival staining produced in the circumlimbal region by silicone hydrogel contact lenses with different edge designs. The secondary objective was to investigate the association between circumlimbal staining and comfort.
  
  
  METHODS
  Four silicone hydrogel contact lenses: ACUVUE OASYS (knife edge design), AIR OPTIX, Biofinity (chisel edge rounded edge combination), and PureVision (rounded edge design), and 1 hydrogel contact lens, ACUVUE 2 (knife edge design), were tested. The study was conducted on a cohort population of 27 established soft contact lens wearers, who wore each contact lens type, in a random order, for a period of 10 (±2) days. Circumlimbal staining was measured in a double-masked fashion through image analysis of digital photographs of lissamine green taken under controlled experimental conditions.
  
  
  RESULTS
  The results obtained showed that contact lens edge design was the primary factor controlling circumlimbal staining for silicone hydrogel lenses: a rounded edge away from the ocular surface produced the lowest staining (average, 0.19%) and a knife edge in close apposition to the ocular surface produced the highest staining (average, 1.34%). Contact lens material rigidity was also identified to affect circumlimbal staining and an inverse association between circumlimbal staining and contact lens comfort was demonstrated: the rounded edge design produced the lowest comfort (72 of 100) and the knife edge design produced the highest (87 out of 100).
  
  
  CONCLUSIONS
  Soft contact lens wear induces circumlimbal staining, the level of staining being influenced by the contact lens edge design. However, high level of circumlimbal staining is not associated with decreased comfort.
authors.affiliation: Department of Optometric Technology Group Research & Consultancy, London, United Kingdom. cmaissa@otg.co.uk
authors.forename: Cécile
authors.initials: C
authors.lastname: Maïssa
authors.forename: Michel
authors.initials: M
authors.lastname: Guillon
authors.forename: Renee J
authors.initials: RJ
authors.lastname: Garofalo
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003228:Conjunctiva; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D005260:Female; D006801:Humans; D020100:Hydrogels; D008086:Lissamine Green Dyes; D008297:Male; D008875:Middle Aged; D010858:Pigmentation; D011474:Prosthesis Design; D011934:Reagent Strips; D012828:Silicones; D055815:Young Adult
chemical_list: D020100:Hydrogels; D008086:Lissamine Green Dyes; D011934:Reagent Strips; D012828:Silicones