Abstract
Purpose :
Misalignment of the optical axis of ophthalmic lenses with the eye's visual system may significantly impact visual performance. Non-coaxial optical designs alter the light energy distribution reaching the retina and may offer visual performance benefits, for example, when optimal alignment cannot be achieved. We assessed the impact of lens misalignment on visual performance of a novel single vision CL design featuring non-coaxial (NC) optics and an aspheric single vision CL design (Biofinity® (BF), Coopervision, USA).
Methods :
Computational simulations based on a realistic eye model (Liou-Brennan) using NC nominal power profiles and BF measured power profiles (NIMO TR1504; Lambda-X, Belgium) were performed in Zemax software. The MTF curves (sagittal and tangential) and higher order aberrations (coma and astigmatism) were evaluated monocularly for 0.25mm, 0.50mm, and 0.75mm decentration of NC and BF (powers -3.0D, -1.0D, +1.0D, and +3.0D) under photopic and scotopic illumination (4mm and 6mm pupils, respectively).
Results :
An example of the impact of decentration on the optical performance of +3.0D and - 3.0D lenses under photopic and scotopic conditions is shown in Table 1. The optical performance for both lenses simulated decreased with decentration (e.g. higher values of coma and astigmatism aberration; Table 1) but a significantly greater impact was observed on BF than the NC lens. The robustness of the NC with decentration was further observed in the MTF curves for powers simulated where no separation of the sagittal and tangential MTF curves occurred (e.g. Fig. 1, +3.0D moderate decentrations) reflecting a symmetric PSF compared with more significant separation (and more asymmetric PSF) for the BF as power becomes more positive and decentration becomes greater (Fig. 1).
Conclusions :
Compared to the aspheric single vision contact lens, the single vision contact lens incorporating non-coaxial optics significantly mitigates the detrimental effects on optical performance induced by lens decentration across different pupil sizes. Non-coaxial optical designs may improve the optical performance of several categories and modalities of ophthalmic lenses.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.