Lack of Diurnal Variation in Vision, Refraction, or Keratometry After Excimer Laser Photorefractive Keratectomy

Abstract

To examine whether diurnal variation in visual acuity, spherical equivalent, keratometry, or intraocular pressure occurs in patients who have undergone photorefractive keratectomy. 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. 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. 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.