In vitro optical performance of a new aberration-free intraocular lens

Abstract

Purpose To assess the optical performance of the new EnVista intraocular lens (IOL). Materials and methods Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL's aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield once they are implanted, an average cornealaberration pattern was juxtaposed to the in-vitro profiles and the same parameters were calculated again. Results For the IOL-only scenario (ie, without including the corneal factor), it was the EnVista IOL, which is aberration-free that showed the higher MTF, PSF values. This was followed by the other two aberrationfree IOL models. However, when the effect of an average corneal pattern was also taken into consideration, the AcrySof IQ IOL SN60WF always outperformed the other neutral-asphericity IOLs. Conclusions The in-vitro optical performance of the EnVista IOL was good, but it decreases substantially in a whole-eye scenario, when the wavefront profile of an average cornea is added. Other designs with different degrees of SA should be considered for this IOL in order to surpass these results.

Comparison of Long-Term Rotational Stability of Three Commonly Implanted Intraocular Lenses

“…An in vitro study showed the superiority of the Acrysof spherical aberration-correcting IOL over the Envista IOL, when the average spherical aberration of the cornea was added to an eye model. 25 The results of tilt in our study are in accordance with an earlier study investigating the crystalline lens and IOL tilt measured by anterior segment optical coherence tomography. Both crystalline lens and IOL showed a tendency to tilt toward the inferotemporal direction.…”

Assessing the in vitro optical quality of presbyopic solutions based on the axial modulation transfer function

“…The measurement of the MTF at a particular spatial frequency as a function of defocus is known as the through-focus MTF. 8 Several studies [9][10][11][12][13][14][15][16][17][18] have evaluated the throughfocus MTF to determine the optical quality of IOLs.…”

Randomized contralateral comparison of visual outcomes following implantation of two monofocal aspherical intraocular lenses after cataract surgery

“…12 On the other hand, EnVista is an aberration-free aspherical IOL to retain minor positive SA for the eyes to maximize the depth of focus. 15 A unique feature of EnVista, stated by its manufacturer, is called glistening-free property. [13][14][15]31 Glistenings are micro-vacuoles that appear within an IOL material, and are commonly seen in hydrophobic acrylic IOLs.…”

“…15 A unique feature of EnVista, stated by its manufacturer, is called glistening-free property. [13][14][15]31 Glistenings are micro-vacuoles that appear within an IOL material, and are commonly seen in hydrophobic acrylic IOLs. They may cause forward-scattering of the light going to the eye, and accordingly degrade visual function.…”

“…In addition to its UV blocking feature and soft 360-degree squared edges, which minimize the possibility of postoperative posterior capsular opacity, one of the unique properties of EnVista is the glistening-free feature. [13][14][15] It was reported that glistening have a significant negative effect on high spatial frequency contrast sensitivity (CS) and visual acuity. [16][17][18] Therefore, the current study was designed to compare postoperative changes in visual acuity (VA), contrast sensitivity (CS), higher-orders aberrations (HOAs), color vision, and satisfaction of the patients following implantation of EnVista IOL in one eye and Acrysof IQ IOL in the other eyes using phacoemulsification cataract surgery.…”