PURPOSE: To verify the morning to evening variations of refraction, visual acuity, intraocular pressure and biomechanical parameters on patients operated by radial keratotomy who presented for refractive re-treatments; and to correlate the biomechanical parameters with refraction, visual acuity and their variations among morning and evening. METHODS: 19 patients were examined, respectively thirty-eight eyes in the morning (9 am) and evening (6 pm), recording sphere-cylindrical dynamic refraction, visual acuity (logMAR) without correction (AVsc) and corrected (AVcc) and ORA (Ocular Response Analyzer) […]