Optical and visual quality with physical and visually simulated presbyopic multifocal contact lenses

16 pags. 6 figs., 1 tab.Purpose: As multifocal contact lenses (MCLs) expand as a solution for presbyopia correction, a better understanding of their optical and visual performance becomes essential. Also, providing subjects with the experience of multifocal vision before contact lens fitting becomes critical, both to systematically test different multifocal designs and to optimize selection in the clinic. In this study, we evaluated the ability of a simultaneous vision visual simulator (SimVis) to represent MCLs. Methods: Through focus (TF) optical and visual quality with a center-near aspheric MCL (low, medium and high near adds) were measured using a multichannel polychromatic Adaptive Optics visual simulator equipped with double-pass, SimVis (temporal multi-plexing), and psychophysical channels to allow measurements on-bench and in vivo. On bench TF optical quality of SimVis-simulated MCLs was obtained from double-pass (DP) images and images of an E-stimulus using artificial eyes. Ten presbyopic subjects were fitted with the MCL. Visual acuity (VA) and DP retinal images were measured TF in a 4.00 D range with the MCL on eye, and through SimVis simulations of the same MCLs on the same subjects. Results: TF optical (on bench and in vivo) and visual (in vivo) quality measurements captured the expected broadening of the curves with increasing add. Root mean square difference between real and SimVis-simulated lens was 0.031/0.025 (low add), 0.025/0.015 (medium add), 0.019/0.011 (high add), for TF DP and TF LogMAR VA, respectively. A shape similarity metric shows high statistical values (lag κ = 0), rho = 0.811/0.895 (low add), 0.792/0.944 (medium add), and 0.861/0.915 (high add) for TF DP/LogMAR VA, respectively. Conclusions: MCLs theoretically and effectively expand the depth of focus. A novel simulator, SimVis, captured the through-focus optical and visual performance of the MCL in most of the subjects. Visual simulators allow subjects to experience vision with multifocal lenses prior to testing them on-eye. Translational Relevance: Simultaneous visual simulators allow subjects to experience multifocal vision non-invasively. We demonstrated equivalency between real multifocal contact lenses and SimVis-simulated lenses. The results suggest that SimVis is a suitable technique to aid selection of presbyopic corrections in the contactology practice.Supported by the European Research Council (ERC-2011-AdC 294099) to SM; Spanish Government (FIS2017-84753R) to SM, and pre-doctoral fellowship (FPU16/01944) to SA; Collaborative agreement with Johnson & Johnson Vision, Inc., Research & Development, Jacksonville, FL, USA

The importance of parameter choice in modelling dynamics of the eye lens

The lens provides refractive power to the eye and is capable of altering ocular focus in response to visual demand. This capacity diminishes with age. Current biomedical technologies, which seek to design an implant lens capable of replicating the function of the biological lens, are unable as yet to provide such an implant with the requisite optical quality or ability to change the focussing power of the eye. This is because the mechanism of altering focus, termed accommodation, is not fully understood and seemingly conflicting theories require experimental support which is difficult to obtain from the living eye. This investigation presents finite element models of the eye lens based on data from human lenses aged 16 and 35 years that consider the influence of various modelling parameters, including material properties, a wide range of angles of force application and capsular thickness. Results from axisymmetric models show that the anterior and posterior zonules may have a greater impact on shape change than the equatorial zonule and that choice of capsular thickness values can influence the results from modelled simulations

Mechanical Properties Of Au Films On Silicon Substrates

This paper presents the results of recent studies of the effects of film thickness on the mechanical properties of electron-beam (e-beam) deposited Au films on silicon substrates. Following a brief description of film microstructure and surface topography, film mechanical properties (Young\u27s modulus and hardness) are determined using nanoindentation techniques. The effects of stiff silicon substrates on the Young\u27s modulus are analyzed within the framework established by King [6, 8]. The effects of indentation size on film hardness are also explained within the context of strain gradient plasticity theories and substrate effects. The plasticity length scale parameters are shown to scale with film thickness. The amount of material pile up is also shown to increase with decreasing film thickness, for a given ratio of indentation depth to film thickness. The implications of the work are discussed for applications of Au films on silicon substrates

Comparison of vision with multifocal contact lenses and SimVis Gekko simulations in a clinical site

ARVO Annual Meeting Abstract, June 202

Ophthalmic lens with an optically non-coaxial zone for myopia control

The present disclosure relates to ophthalmic devices such as ophthalmic lenses. An ophthalmic device may comprise an ophthalmic lens for at least one of slowing, retarding or preventing myopia progression. The ophthalmic lens may comprise a center zone with a negative power for myopic vision correction; and at least one treatment zone surrounding the center zone, the at least one treatment zone having a power profile comprising an ADD power, the at least one treatment zone having a surface shape comprising a portion of a generally toroidal shape, wherein the at least one treatment zone is arranged as to form a continuous surface with the center zone

The Zonules Selectively Alter the Shape of the Lens During Accommodation Based on the Location of Their Anchorage Points

PURPOSE. To determine the role of anterior and posterior zonular tension on the optomechanical lens response during accommodation simulation. METHODS. Ten eyes from nine hamadryas baboons (4.9 ± 0.7 years) and 20 eyes from 18 cynomolgus monkeys (5.4 ± 0.3 years) were dissected, leaving the lens, zonules, ciliary body, hyaloid membrane, anterior vitreous, and a segmented scleral rim intact. The lens preparation was mounted in a lens stretcher, and the outer scleral shell was displaced radially in a stepwise fashion. The load, lens, and ciliary body diameters, lens power, lens thickness, and the anterior and posterior radius of curvature were measured during stretching. The zonular fibers attached to either the posterior or anterior lens surface were then carefully transected and the experiment was repeated. Zonular transection was confirmed in four eyes via laser scanning confocal microscopy after immunostaining. The effect of zonular transection on the tissue response to stretching was quantified. RESULTS. Without anterior zonules, 48% and 97% of the changes in anterior and posterior radii are retained. Without posterior zonules, 81% and 67% of the changes in anterior and posterior radii are retained. The changes in lens shape were reduced after transecting either the anterior or posterior zonules; however, both surfaces still changed shape. CONCLUSIONS. While either the anterior or posterior zonules alone are capable of changing the shape of both lens surfaces, the anterior zonules have a greater effect on the anterior lens surface, and the posterior zonules have a greater effect on the posterior lens surface

Optical and visual quality with physical and visually simulated presbyopic multifocal contact lenses

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019Support European Research Council ERC-2011-AdG-294099; Spanish Government: FIS2017-84753-R, PTQ-15-07432, and ISCIII DTS16/00127; Spanish Goverment predoctoral program FPU16/01944; Collaborative agreement with Johnson & Johnson Vision, Inc., Jacksonville, FL, USAPeer reviewe