To evaluate and compare, by scanning electron microscopy (SEM), the sharpness of the edge of brand new surgical blades and consecutively used surgical blades in phacoemulsification. All studies were approved by the institutional Animal Care and Use Committee and were in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Twenty-five angled ophthalmic knife were evaluated after corneal incision in rabbits. The subjects were divided in five groups with five surgical blades each group: Group 1 (control), nonused surgical blades; Group 2, five surgical blades used once; Group 3, five surgical blades used twice; Group 4, five surgical blades used four times; Group 5, five surgical blades used six times. Immediately after incision the surgical blade was mounted on 10 mm aluminum stubs with double-sided tape and examined using scanning electron microscope operating at 15 kV. Each blade was analyzed by SEM at five random points, two central and three peripheral points, with magnification of 30x, 50x, 350x and 1,000x. Ten photomicrographs of each surgical blade were obtained. Blade body irregularities and organic material were observed on all used surgical blades (Groups 2, 3, 4 and 5), but not on new surgical blades (Group 1). In addition, Group 5 revealed more irregularities. Reusing blades for phacoemulsification may produce structural changes and its clinical implications need to be evaluated due to the possible relation with postoperative complications. Moreover, reusing blades are not recommended for the surgical operation because the priority should be given to patients' safety.