Influence of angle Kappa on the optimal intraocular orientation of asymmetric multifocal intraocular lenses

• Published in: Journal of optometry Vol. 14; no. 1; pp. 78 - 85
• Main Authors: Bonaque-González, Sergio, Jaskulski, Matt T., Carmona-Ballester, David, Pareja-Ríos, Alicia, Trujillo-Sevilla, Juan M.
• Format: Journal Article
• Language: English
• Published: Spain Elsevier España, S.L.U 01.01.2021; Elsevier
• Subjects: Kappa angle; Multifocal intraocular lenses; Original; IQ; LoS; Multifocal intraocular lenses; Κ; Kappa angle; MIOL
• ISSN: 1888-4296; 1989-1342
• DOI: 10.1016/j.optom.2020.07.004

to evaluate the effects of kappa angle and intraocular orientation on the theoretical performance of asymmetric multifocal intraocular lenses (MIOL). For a total of 21 corneal aberrations, a computational analysis simulated the implantation of a computationally designed MIOL. An image quality parameter (IQ) (visually modulated transfer function metric) was calculated for a 5.0-mm pupil and for three conditions: distance, intermediate, and near vision. The procedure was repeated for each eye after a rotation of the MIOL with respect to the cornea from 0º to 360º in 5º steps. Kappa angles from 0 to 900 microns, in 150 microns steps, combined with two two variants of MIOL centration were tested: in the corneal apex or in the center of the entrance pupil. A p-value ≤ 0.05 was considered significant. There were statistically significant differences of the IQ depending of the intraocular orientation of the MIOL. If kappa angle was increased, there was a statistically significant decrease of the IQ. The IQ maintained stable when the optimal intraocular orientation was re-calculated for each kappa angle. In general, the inter-variability of the results between subjects was very high. There were no strong evidences supporting that there exists a preferable centration point. Our results suggest that kappa angle theoretically affects significantly the performance of asymmetric MIOL implantation. However, its negative effect can be compensated if a customized intraocular orientation is calculated taking into account the presence of the kappa angle.