title: Evaluation of the performance of photochromic spectacle lenses in children and adolescents aged 10 to 15 years.
abstract: BACKGROUND
  To compare the performance of clear and photochromic spectacle lenses in children and adolescents, with respect to visual acuity and satisfaction with day-to-day activities.
  
  
  METHODS
  Fifty full-time spectacle wearers, aged 10 to 15 years, were randomly assigned to wear clear and Transitions photochromic spectacle lenses for two weeks each in a crossover fashion. Subjects were evaluated at screening, lens delivery and two weeks post-delivery. At each visit, distance and near visual acuity (VA, logMAR) were assessed and subjective questionnaires, using Likert scales, were administered. Parents/guardians also completed questionnaires at entry and exit from the study.
  
  
  RESULTS
  There were no significant differences in VA between clear and photochromic lenses (p > 0.05) and no difficulties were encountered with completion of the questionnaires. Subjective evaluation of vision in bright sunlight and when playing sport was significantly better with photochromic compared to clear lenses (p < 0.05). There were no significant differences between lens designs in subjective performance indoors, such as in the classroom or when reading (p > 0.05). Forty-three subjects (88 per cent) chose to continue wearing photochromic lenses on conclusion of the trial. Thirty subjects (61 per cent) preferred photochromic over clear lenses due to reasons such as darkening in sunlight, better vision and less squinting in sunlight. Forty-three parents (88 per cent) rated the children's overall experience with photochromic lenses to be favourable or very favourable.
  
  
  CONCLUSIONS
  Photochromic lenses can be successfully prescribed for children and adolescents aged 10 to 15 years. Clear and photochromic lenses were considered to be equivalent for indoor activities; however, photochromic lenses were significantly preferred over clear lenses for outdoor activities. Likert grading scales can be used effectively in questionnaires for children and adolescents and further development of questionnaires for use in clinical trials evaluating lens performance in children is warranted.
authors.affiliation: Clinical Vision Research, Carlton, Australia. clakkis@unimelb.edu.au
authors.forename: Carol
authors.initials: C
authors.lastname: Lakkis
authors.forename: Kate
authors.initials: K
authors.lastname: Weidemann
mesh_terms: D000221:Adaptation, Ocular; D000293:Adolescent; D002648:Child; D018592:Cross-Over Studies; D005135:Eye Protective Devices; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017060:Patient Satisfaction; D011446:Prospective Studies; D011832:Radiation Injuries / Q000150:complications / Q000517:prevention & control*; D011795:Surveys and Questionnaires; D014466:Ultraviolet Rays / Q000009:adverse effects; D014786:Vision Disorders / Q000209:etiology / Q000517:prevention & control*; D014792:Visual Acuity