title: Lack of diurnal variation in vision, refraction, or keratometry after excimer laser photorefractive keratectomy.
abstract: OBJECTIVE
  To examine whether diurnal variation in visual acuity, spherical equivalent, keratometry, or intraocular pressure occurs in patients who have undergone photorefractive keratectomy.
  
  
  METHODS
  Twenty-nine post-photorefractive keratectomy patients underwent morning and evening measurements of visual acuity, spherical equivalent, keratometry, and intraocular pressure at intervals between 5 and 13 months after photorefractive keratectomy.
  
  
  RESULTS
  There was no statistically significant post-photorefractive keratectomy diurnal variation in visual acuity, spherical equivalent, or keratometry in the group studied. Diurnal variation in post-photorefractive keratectomy intraocular pressure was not significantly different between patients' treated and untreated eyes.
  
  
  CONCLUSIONS
  Photorefractive keratectomy does not appear to result in diurnal variation in visual acuity, spherical equivalent, or keratometry post-operatively, nor does it seem to effect normal diurnal variation in intraocular pressure.
authors.affiliation: Department of Ophthalmology, New York Eye and Ear Infirmary, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Goldberg
authors.forename: D A
authors.initials: DA
authors.lastname: Dorr
authors.forename: J S
authors.initials: JS
authors.lastname: Pepose
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*