title: Effect of a yellow filter on contrast sensitivity and disability glare after laser in situ keratomileusis under mesopic and photopic conditions.
abstract: OBJECTIVE
  To analyze the effect of a yellow filter on contrast sensitivity and disability glare under mesopic and photopic luminance conditions in laser in situ keratomileusis (LASIK) patients and control subjects.
  
  
  METHODS
  Contrast sensitivity with and without glare was determined in 27 patients who had undergone LASIK at least 1 year previously and in 30 control subjects. Tests were performed with and without a coated yellow filter (X-482 nm cut-off) using the Mesotest II or Mesoptometer II (Oculus, Wetzlar, Germany) under mesopic conditions, and the Contrast Glaretester 1000 (Takagi, Seiko Co Ltd, Nagano, Japan) under photopic conditions.
  
  
  RESULTS
  Under mesopic conditions, log contrast sensitivity without glare decreased by 0.14 log units in the LASIK group. When the yellow filter was used, this variable showed a significant increase of 0.04 log units and the proportion of patients able to discriminate the mesopic contrast limit of 1:5 rose from 70% to 78%. With glare, the yellow filter also improved contrast sensitivity in LASIK patients, but not significantly. Under photopic conditions, no statistical differences were observed between results obtained with and without the yellow filter in the LASIK group or between the LASIK and control group without glare.
  
  
  CONCLUSIONS
  Mesopic contrast sensitivity without glare was worse in LASIK patients and increased significantly with the yellow filter. The filter had no effect under photopic conditions. No disability glare differences were noted between the LASIK and control groups or between the LASIK without and with filter groups under mesopic and photopic conditions.
authors.affiliation: Department of Optics, School of Optometry, Complutense University of Madrid, Spain. mjpc@opt.ucm.es
authors.forename: M Jesús
authors.initials: MJ
authors.lastname: Pérez-Carrasco
authors.forename: M Cinta
authors.initials: MC
authors.lastname: Puell
authors.forename: Celia
authors.initials: C
authors.lastname: Sánchez-Ramos
authors.forename: Angel
authors.initials: A
authors.lastname: López-Castro
authors.forename: Antonio
authors.initials: A
authors.lastname: Langa
mesh_terms: D000328:Adult; D003116:Color; D015350:Contrast Sensitivity / Q000502:physiology*; D004185:Disability Evaluation; D005139:Eyeglasses; D005260:Female; D019466:Glare; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery; D011183:Postoperative Complications; D012029:Refraction, Ocular / Q000502:physiology; D016896:Treatment Outcome; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*