Enhancing the Intermediate Vision of Monofocal Intraocular Lenses Using a Higher Order Aspheric Optic

Abstract

B efore the introduction of the aspheric technology, the standard of care was the use of monofocal spherical intraocular lenses (IOLs) that have spherical optical surfaces that are well known to induce (positive) primary spherical aberration. The spherical aberration of spherical IOLs adds to the spherical aberration originating from the cornea, increasing the total spherical aberration of the eye and limiting the distance image quality of the pseudophakic eye. 1-3 Aspheric IOLs have been developed to either compensate for the lens' intrinsic spherical aberration ("aberration neutral" or "zero aberration" IOLs) or the corneal spherical aberration (aberration-correcting IOL). 3 Previous studies have shown that aspheric IOLs that fully ABSTRACT PURPOSE: To describe and evaluate a new monofocal intraocular lens (IOL) designed to improve intermediate vision using a unique refractive technology. METHODS: The new monofocal lens is based on a higher order aspheric optic and is designed to improve intermediate vision. Simulated visual acuity from far to-2.00 diopters (D) was calculated using optical bench data. The effect of corneal higher order aberrations (HOAs) on simulated visual acuity, pupil size, and decentration was assessed using realistic computer eye models. The susceptibility to photic phenomena was evaluated by measuring preclinically the intensity of the light distribution in the retinal plane. The new lens design was compared to a standard aspheric monofocal IOL that shares the same platform, material, and primary spherical aberration as the new design. RESULTS: Simulated defocus curves showed increased simulated visual acuity in the intermediate range compared to a standard aspheric monofocal IOL with comparable distance vision, independently of the pupil size and corneal HOAs. At-1.50 D, the new IOL design provided a gain of approximately 0.1 logMAR, whereas at distance, the difference was less than 0.05 logMAR. The tolerance to decentration was also similar in both designs. Finally, experimental results indicate that the susceptibility to photic phenomena with the new lens design was similar to that of a standard aspheric monofocal IOL. CONCLUSIONS: Preclinical data showed that the new lens design improves intermediate vision while maintaining comparable distance image quality and keeping the same photic phenomena profile as a standard aspheric monofocal IOL.

Visual Performance and Optical Quality after Implantation of a New Generation Monofocal Intraocular Lens

“…They are visually indistinguishable from the same platform-standard monofocal lOLs. Their unique anterior surface and a thickness difference of 1.5 microns with a diameter of nearly 2 mm in the optical center enable a power increase of approximately 0.5 D [21]. The increase in power distribution from the periphery to the center enhances the depth of focus and enriches intermediate vision [8].…”

Laboratory Investigation of Preclinical Visual-Quality Metrics and Halo-Size in Enhanced Monofocal Intraocular Lenses

“…The wOTFb change with defocus (where b is -0.36) has been reported to correlate strongly with clinically measured VA, and we compared this change between models [7,22]. A polychromatic point spread function (PSF), i.e., an image of a 0.1-mm pinhole, was used to assess the size of halos projected by the IOLs at the 4.5-mm aperture [4,16]. A long transformation of each recorded image was applied, and the background noise was removed.…”

“…Objective metrics derived from in vitro assessment of IOLs are widely used to evaluate the performance of new lens models [4][5][6][7][8][9][10] or failed implants [11,12]. One such metric is the optical transfer function (OTF) that represents the imaging ability of an optical system.…”

“…Thus, this postoperative complaint is typically associated with multifocal IOLs rather than monofocal ones [15,16]. Recent clinical and laboratory studies demonstrated a comparable amount of dysphotopsia with the ICB00 and the control monofocal Tecnis IOL [2][3][4][5], which may be used as a reference to test the susceptibility of new mono-EDoF designs to produce such phenomena.…”

“…In another clinical investigation, higher spectacle independence was observed at the intermediate range with the ICB00 compared to a monofocal lens [ 3 ]. The performance of the ICB00 has also been documented in laboratory studies [ 4 , 5 ]. In those reports, however, only one IOL model has been evaluated.…”