Lack of diurnal variation in vision, refraction, or keratometry after excimer laser photorefractive keratectomy

PURPOSE: 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 inpost-photorefractive keratectomy intraocular pressure was not significantly different between patients' treated and untreated eyes. CONCLUSION: Photorefractive keratectomy does not appear to result in diurnal variation in visual acuity, spherical equivalent, or keratometry postoperatively, nor does it seem to effect normal diurnal variation in intraocular pressure.