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

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).

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.

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.

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. [.