title: Hydrogel contact lens binding induced by contact lens rewetting drops.
abstract: OBJECTIVE
  To investigate alterations in prelens tear film (PLTF), contact lens (CL), and postlens tear film (PoLTF) thicknesses and contact lens movement associated with boric acid-containing rewetting drops.
  
  
  METHODS
  This was a single-center, randomized, double-masked clinical trial. Following etafilcon A lens application, baseline lens movement and interferometric measures (PLTF, CL, PoLTF thicknesses) were captured. A randomly assigned drop (either a low or high boric acid-containing drops) was applied to both eyes, followed immediately by lens movement and interferometric measures. After a 2-h washout period (spectacle wear), subjects returned for testing with the alternative drop. Statistical analyses addressed pre- to postdrop changes in lens movement and PLTF, CL, and PoLTF thickness.
  
  
  RESULTS
  The presence of a drop alone lead to substantial decreases in contact lens movement (general reduction of 0.45 mm), but the reduction was not related to drop type. The presence of a drop led to an increase in PLTF thickness (approximately 0.14 microm), again regardless of the drop type. Both the general presence of a rewetting drop and drop type lead to an increase in CL center thickness (lower boric acid drop = 0.31 microm and higher boric acid drop = 1.13 microm). Both the general presence of a rewetting drop and the drop type lead to a significant decrease in PoLTF thickness, whereby the lower boric acid drop lead to a decrease of 0.28 mum and the higher boric acid drop lead to a decrease of 0.73 microm.
  
  
  CONCLUSIONS
  Boric acid-containing rewetting drops were shown to be associated with a significant reduction in lens movement with a concurrent increase in lens center thickness and reduction in PoLTF thickness. The higher boric acid-containing drop was associated with more substantial increases in lens center thickness and decreases in PoLTF thickness.
authors.affiliation: The Ohio State University, College of Optometry, Columbus, Ohio 43210, USA. nichols.142@osu.edu
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Nichols
authors.forename: Loraine T
authors.initials: LT
authors.lastname: Sinnott
authors.forename: P Ewen
authors.initials: PE
authors.lastname: King-Smith
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Nagai
authors.forename: Sadayasu
authors.initials: S
authors.lastname: Tanikawa
mesh_terms: D000328:Adult; D003261:Contact Lenses; D004867:Equipment Design; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008297:Male; D009068:Movement; D009883:Ophthalmic Solutions; D013666:Tears / Q000502:physiology
chemical_list: D009883:Ophthalmic Solutions; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate