No abstract

This study aimed to evaluate in vitro performance refractive segmented EDOF intraocular lenses under polychromatic light using an optical bench that complies with the ISO 11979-2 Norm. The through focus modulation transfer function (TF-MTF) of the Femtis Comfort LS-313 MF15 (Oculentis GmbH, Berlin, Germany) IOL was evaluated for IOLs with three different base powers. The effect of the asymmetry of the segmented designs was evaluated with 3 different wavelengths and with polychromatic light at a 3.0 mm and 5.0 mm pupil diameter. It was demonstrated that the TF-MTF curves exhibit a bifocal profile that, in practice, results in an EDOF design. As a consequence of the LCA, the TF-MTF values in white light were lower than in monochromatic light. Images of the USAF test chart were obtained to confirm the prediction of the TF-MTFs. We found that Femtis Comfort is a bifocal low-addition IOL and this fact can result in an EDOF effect which was obtained previously in clinical trials. Moreover, we showed that the base power influences the IOL optical quality, which results as more effective for high powers (hyperopic eyes) than for low powers (myopic eyes). The LCA of the segmented refractive design was very low and presumably not clinically relevant.

Background: Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens. Methods: The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator. Results: Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range. Conclusions: Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients.

Evaluating chromatic aberration for a multifocal intraocular lens (MIOL) in vitro is essential for studying its performance because it helps determine the most appropriate lens for each patient, enhancing surgical outcomes. While refractive MIOLs with angular power variation have shown positive clinical outcomes, studies of these MIOLs on optical benches primarily employed monochromatic green light, neglecting the impact of longitudinal chromatic aberration (LCA) on MIOL performance. To address this gap, we evaluated the through-focus modulation transfer function (TF-MTF) and the point spread function (PSF) of two refractive segmented extended depth of focus intraocular lenses (IOLs) (Femtis Comfort and Precizon Presbyopic), comparing the results with those obtained with two widely known diffractive multifocal intraocular lenses (AcrySof IQ ReSTOR and FineVision Pod F). Measurements of the TF-MTF were conducted using both monochromatic and polychromatic light in a customized optical bench. The refractive designs exhibited distinct haloes in the PSFs. When comparing the refractive and diffractive designs, opposite signs of LCA were observed at near foci. These findings emphasize the influence of the optical design of IOLs on their performance under polychromatic light, providing valuable information for vision care professionals when selecting the most suitable lens for each patient.

This study aimed to evaluate the optical performance of a rotationally asymmetric intraocular lens (IOL) when it is decentered relative to the visual axis. The FEMTIS Comfort IOL (Teleon Surgical B.V., Spankeren, The Netherlands) was assessed using ray tracing software in the Atchison model eye at apertures of 3.0 mm and 4.5 mm. The metric used for assessment was the through-the-focus area under the modulation transfer function (TF-MTFa). Decentrations of 0.2 mm and 0.4 mm were considered. Our results indicated that the MTFa defocus curves exhibited significant differences depending on the direction of vertical decentration. Downward decentrations shifted the MTFa curve towards virtual vergences, resulting in improved optical quality at far distances but decreased optical quality at intermediate and near vision. Conversely, upward decentrations produced the opposite effect. Since, on one hand, this lens is fixed within the capsulorhexis during surgery, demonstrating excellent stability, and on the other hand, the precise centration of the capsulorhexis can be made accurately off the visual axis, these results provide surgeons with the opportunity to plan various clinical scenarios to optimize surgical outcomes with this IOL by selecting the optimal location for capsulorhexis centration in each patient.