In Vitro Comparison of an Aspherical Monofocal Lens Inducing Positive Spherical Aberrations With a Spherical Lens.

Abstract

Purpose: To compare the in vitro performance of a monofocal intraocular lens (IOL) with an aspherical design inducing positive spherical aberrations (APSA IOL, RayOne EMV; Rayner), and a spherical lens (RayOne Spheric; Rayner).

Methods: In vitro wavefront measurements were conducted on 10.00, 20.00, and 30.00 diopter (D) lenses. The average through-focus modulation transfer function (MTF) (0 to 50 lp/mm) was generated for 168 synthetic numerical eye models with varying aperture sizes (2.0 to 5.5 mm) and corneal spherical aberration values (-0.49 to 0.91 µm). Evaluated metrics included MTFmax (peak MTF value) and depth of focus (DOF), defined as half of the dioptric range in the spectacle plane where the MTF exceeds 0.3.

Results: In physiological corneal models, APSA IOLs demonstrated enhanced MTFmax and DOF in larger apertures in high power lenses (30.00 D); a similar, although less pronounced, pattern was observed at 20.00 D. For low-power (10.00 D) lenses, APSA IOLs provided superior MTFmax in large apertures but exhibited a moderate trade-off in mid-sized apertures. In non-physiological corneal models with high SA, both APSA IOLs and spherical lenses showed reduced MTFmax in larger apertures. Conversely, in negative spherical aberration models, they provided excellent MTF-max but limited DOF.

Conclusions: In normal eyes, APSA IOLs offer better contrast rendering and DOF in high-power lenses due to the controlled induction of positive spherical aberration. However, in medium-power and low-power lenses, the benefits are less evident, with low-power lenses showing reduced contrast in mid-sized pupils. Caution is advised for both models following myopic corneal refractive surgery, although they perform well after hyperopic treatment. [J Refract Surg. 2025;41(5):e481-e491.].