LACK OF DIURNAL-VARIATION IN VISION, REFRACTION, OR KERATOMETRY AFTEREXCIMER-LASER PHOTOREFRACTIVE KERATECTOMY

PURPOSE: To examine whether diurnal variation in visual acuity, spheri cal equivalent, keratome try, or intraocular pressure occurs in patien ts who have undergone photorefractive keratectomy. METHODS: Twenty nin e post photorefractive keratectomy patients underwent morning and even ing measurements of visual acuity, spherical equivalent, keratometry, and intraocular pressure at intervals between 5 and 13 months after ph otorefractive keratectomy. RESULTS: There was no statistically signifi cant post-photorefractive keratectomy diurnal variation in visual acui ty, spherical equivalent, or keratometry in the group studied. Diurnal variation in post-photorefractive keratectomy intraocular pressure wa s not significantly different between patients' treated and untreated eyes. CONCLUSION: Photorefractive keratectomy does not appear to resul t in diurnal variation in visual acuity, spherical equivalent, or kera tometry post-operatively, nor does it seem to effect normal diurnal va riation in intraocular pressure.