Corneal thickness values before and after oxybuprocaine 0.4% eye drops

PURPOSE: To determine changes in corneal thickness after topical anesthesia. METHODS: Corneal thickness was measured before and 3 minutes after administration of two drops of oxybuprocaine 0.4% to 26 patients (26 eyes). We analyzed the corneal thickness of a control group, which was made up of 26 patients (26 eyes) before and 3 minutes after administration of two drops of saline solution. Corneal thickness was measured with the Orbscan Topography System II (Bausch Lomb Surg., Barcelona). RESULTS: Variations higher than +/- 10 microm were found following the instillation of 2 oxybuprocaine eye drops in eight eyes (30.76%) at the inferonasal cornea, in six eyes (23.08%) at the superotemporal, temporal and inferotemporal cornea, in five eyes (19.23%) at the nasal cornea, in three eyes (11.53%) at the central cornea, and in two eyes (7.69%) at the superonasal cornea. Nevertheless, no significant differences in the mean corneal thickness at each corneal location between the first and the second corneal thickness measurements were found in anesthetized eyes. CONCLUSIONS: Some individuals can present important increases and decreases in corneal thickness values after anesthetic eye drops. This effect of anesthetic eye drops must be considered by refractive surgeons when carrying out preoperative laser in situ keratomileusis corneal thickness measurements.