title: Visual experiences during different stages of LASIK: Zyoptix XP microkeratome vs Intralase femtosecond laser.
abstract: OBJECTIVE
  To describe the loss of light perception and other visual experiences encountered during different stages of laser in situ keratomileusis (LASIK) and to compare patients' experiences between LASIK performed with the Zyoptix XP microkeratome and Intralase laser.
  
  
  METHODS
  Prospective, randomized, self-matched clinical study.
  
  
  METHODS
  Forty-one patients (82 eyes) had bilateral LASIK with the corneal flap fashioned by Zyoptix XP microkeratome in one eye and Intralase laser in the other. They were interviewed postoperatively with a standardized questionnaire about their intraoperative visual experiences, including light perception and ability to see the red fixation light.
  
  
  RESULTS
  During both vacuum suction and corneal flap fashioning, a higher proportion of eyes in the Zyoptix XP microkeratome group lost light perception compared with the Intralase group (85.4% vs 39.0% and 90.2% vs 61.0%; P < .001 and P = .004, respectively). Patients also saw flashes, various colors, movement, the surgeon's hands or fingers, and the surgeon during surgery, and there was no difference in these visual experiences between the Zyoptix XP microkeratome and Intralase groups. Overall, eight (19.5%) of 41 patients were frightened by their intraoperative visual experiences during LASIK.
  
  
  CONCLUSIONS
  Patients retain light perception during most stages of LASIK except during suction and fashioning of the corneal flap, when some are temporarily unable to see. Many also experience various visual sensations intraoperatively, and 19.5% of patients are frightened by their visual experiences.
authors.affiliation: The Eye Institute at Tan Tock Seng Hospital, National Healthcare Group, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Colin S H
authors.initials: CS
authors.lastname: Tan
authors.forename: Kah-Guan
authors.initials: KG
authors.lastname: Au Eong
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Lee
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D008027:Light; D008297:Male; D009216:Myopia / Q000601:surgery*; D017060:Patient Satisfaction; D011446:Prospective Studies; D012677:Sensation / Q000502:physiology; D013524:Surgical Flaps; D011795:Surveys and Questionnaires; D014788:Vision, Entoptic / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*