title: Effects of contact lenses on the ocular surface in patients with keratoconus: piggyback versus ClearKone hybrid lenses.
abstract: OBJECTIVE
  Because patients with keratoconus tend to wear contact lens for a long period of time, they are more prone to ocular surface changes induced by the lenses. This study aimed to compare immunohistochemical changes induced by two different types of contact lenses in patients with keratoconus.
  
  
  METHODS
  Twenty-four contact lens-naive keratoconus patients (30 eyes) were included in this prospective study. Group 1 comprised 14 eyes (12 patients) wearing piggyback lenses, and group 2 comprised 16 eyes (12 patients) wearing ClearKone hybrid lenses. The patients were analyzed for bulbar conjunctival impression cytology, tear interleukin-6 (IL-6) and IL-8 levels, and confocal microscopic changes of the cornea before and 6 months after wearing contact lenses.
  
  
  RESULTS
  Six months after wearing contact lenses, the groups demonstrated similar epithelial metaplasia rates, tear IL-6 and IL-8 levels, and similar confocal microscopy findings (P>0.05 for all intergroup comparisons). Among the parameters tested in this study, only IL-6 and IL-8 levels and posterior keratocyte density on confocal microscopy showed an increase after 6 months when compared with baseline values but at a similar degree in the two groups.
  
  
  CONCLUSIONS
  This small sample was not able to demonstrate a difference between the two types of lenses with regard to the variables examined, and further larger trials would be required to determine if differences truly exist or not. However, clinicians may still consider patient comfort and vision in selecting the lens type in patients with keratoconus.
authors.affiliation: Haydarpasa Numune Education and Research Hospital, Ophthalmology Clinic, Istanbul, Turkey. torunbanu@yahoo.com
authors.forename: Banu Torun
authors.initials: BT
authors.lastname: Acar
authors.forename: Ece Turan
authors.initials: ET
authors.lastname: Vural
authors.forename: Suphi
authors.initials: S
authors.lastname: Acar
mesh_terms: D000328:Adult; D003228:Conjunctiva / Q000473:pathology*; D003261:Contact Lenses; D003263:Contact Lenses, Hydrophilic; D060527:Corneal Keratocytes / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007640:Keratoconus / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D008297:Male; D011446:Prospective Studies; D013666:Tears / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015850:Interleukin-6; D016209:Interleukin-8