Visual performance after toric IOL implantation in patients with corneal astigmatism

Purpose: To analyze visual acuity without correction and rotational stability outcomes following toric IOL implantation. Methods: Prospective study of 20 eyes of 13 patients that underwent phacoemulsification surgery indicated for cataract associated with regular keratomeric astigmatism, symmetrical, ranging from 1 to 4 diopters. Best corrected visual acuity, refraction, keratometry and computed topography were performed preoperatively. The calculation of cylindrical lens power and its placement were determined by the manufacturer. All lenses were implanted in the capsular bag by the same surgeon. The patients were examined by a second independent observer, at 1(st), 10(th), 20(th), 30(th), and 60(th) postoperative day. Results: Visual acuity without correction ranged between 20/15 and 20/40. One eye achieved 20/15 (5%), 4 eyes 20/20 (20%), 6 eyes 20/25 (30%), 7 eyes 20/30 (35%) and 2 eyes 20/40 (10%). Best corrected visual acuity ranged between 20/15 and 20/40; two eyes with 20/15 (10%), 9 eyes 20/20 (45%), 7 eyes 20/25 (35%), 1 eye 20/30 (5%) and 1 eye 20/40 (5%). It is important to remember that the average spherical refraction was -0.05 SD (ranging from -0.50 to + 0.75 SD). The mean cylindrical refraction was -0.63 CD ranging from -0.50 to -1.25 CD. The IOL rotation in this study had an average of 3.2 degrees to 30 degrees, ranging from 0 degrees of rotation to a maximum of 13 degrees; 7 lenses (35%) suffered no rotation, 9 lenses (45%) suffered rotation between 1 degrees to 5 degrees, 3 lenses (15%) had rotation between 6 degrees to 10 degrees, and ultimately 1 lens (5%) had rotation between 11 degrees to 15 degrees. There was no significant rotation after the 30(th) postoperative day. Discussion: The average of rotation of the IOL was 3.2 degrees, where 95% of IOLs presented rotation less than or equal to 10 degrees what means a very good rotational stability. In daily practice, a good visual acuity is directly related to IOL rotational stability and refractive predictability.