title: Effects of wearing a daily disposable lens on tear film: a randomised controlled trial.
abstract: OBJECTIVE
  Contact lens-induced dry eye is commonly encountered, although its extent is not well documented with daily disposable lenses. A novel type of contact lens system incorporating moisturising agent (alginic acid) has been developed. The aim of this study was to evaluate the effect of wearing daily 2-hydroxyethyl methacrylate disposable contact lenses for seven days on tear stability, conjunctival and limbal redness and dry eye symptoms. Then, we aimed to determine whether lens solutions containing alginic acid had any influence on tear parameters.
  
  
  METHODS
  This was a seven-day parallel group double-masked clinical trial of previous contact lens wearers, where participants were randomly assigned to wearing SEED 1dayPure moisture contact lenses with (n = 15) or without alginic acid (n = 15). Tear lipid layer thickness (LLT), non-invasive tear break-up time (NIBUT), conjunctival redness, corneal fluorescein staining, tear break-up time and Schirmer I readings were measured. Symptom severity and frequency were evaluated and combined using a global score from visual analogue scales.
  
  
  RESULTS
  The mean age and standard deviation of the participants was 25 ± 3.8 years. There were 24 females and six males. After reintroduction of contact lens wear for one week, there was significant improvement in the global symptom score; however, this may not be clinically significant. There were small and clinically insignificant changes in limbal and conjunctival hyperaemia but no significant changes in lipid layer thickness, Schirmer I and NIBUT in overall participants. The use of alginic acid in lens solutions did not affect these parameters compared to control lenses (p > 0.05).
  
  
  CONCLUSIONS
  After seven days of wearing a modern daily disposable lens, there was no significant deterioration of tear function in a group of young contact lens wearers. In this short-term study, there was no evidence of significant benefit of lens solutions containing alginic acid used with HEMA lenses.
authors.affiliation: National University of Singapore Yong Loo Lin School of Medicine, Singapore.
authors.forename: Pamela Qin Yi
authors.initials: PQ
authors.lastname: Chong
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Sharon
authors.initials: S
authors.lastname: Yeo
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Cheah Loon
authors.initials: CL
authors.lastname: Too
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Boo
authors.affiliation: National University of Singapore Yong Loo Lin School of Medicine, Singapore. Louis.tong.h.t@snec.com.sg.|Singapore Eye Research Institute, Singapore. Louis.tong.h.t@snec.com.sg.|Singapore National Eye Centre, Singapore. Louis.tong.h.t@snec.com.sg.|Duke-National University of Singapore Graduate Medical School, Singapore. Louis.tong.h.t@snec.com.sg.
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
mesh_terms: D000328:Adult; D003263:Contact Lenses, Hydrophilic; D004311:Double-Blind Method; D015352:Dry Eye Syndromes / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008689:Methacrylates; D013666:Tears
chemical_list: D008689:Methacrylates; C005044:hydroxyethyl methacrylate
keywords: alginic acid; clinical study; contact lens; dry eye; human; prospective study; randomised control trial; tears