References of "Loicq, Jerôme"
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See detailA NEW TRIFOCAL DESIGN
Gatinel, Damien; Loicq, Jerôme ULiege

Conference (2017, October 06)

Purpose: Contributions of IOL biomaterial (Abbe #) and diffractive pattern topography on LCA of various types of multifocal IOLs. Methods: The LCAs associated with the different focal points of ... [more ▼]

Purpose: Contributions of IOL biomaterial (Abbe #) and diffractive pattern topography on LCA of various types of multifocal IOLs. Methods: The LCAs associated with the different focal points of diffractive hydrophobic – made of aromatic and/or aliphatic materials – and hydrophilic multifocal IOLs were experimentally determined on an optical bench in RGB conditions (650, 546 and 480 nm). The effects of Abbe number and of the topography of the different diffractive profiles were evaluated. Based on wavelength–dependent MTF through-focus curves, polychromatic behavior of multifocal IOLs was assessed. Results: LCA amplitudes and signs were different for each of the focal points. While far vision LCA was of negative sign and appeared to be controlled by the material Abbe number, the diffractive LCA for near and intermediate visions was independent of IOL material. The diffractive pattern characteristics, which control the closer distance powers, prove to be pivotal in fine-tuning the LCA related to these near and intermediate foci. Conclusions: Diffractive multifocal IOLs show chromatic aberrations with are controlled by the biomaterial Abbe number for its refractive component on the one hand, and by the topography of the diffractive pattern for the second component on the other hand. [less ▲]

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See detailLongitudinal Chromatic Aberration discussion on diffractive intraocular lenses
Loicq, Jerôme ULiege; Gatinel, Damien

Conference (2017, October 06)

Diffractive multifocal IOLs show chromatic aberration especially along the axis (LCA-longitudinal Chromatic aberration) but also out of the optical axis. These chromatic aberrations are the results of the ... [more ▼]

Diffractive multifocal IOLs show chromatic aberration especially along the axis (LCA-longitudinal Chromatic aberration) but also out of the optical axis. These chromatic aberrations are the results of the refractive chromatic properties of the lens, driven by refractive indexes involved into the light path and the diffractive profiles. Refractive effects are mainly controlled by the biomaterial Abbe number while diffractive effects are controlled by the topography of the diffractive pattern. The insertion of a multifocal diffractive lens after crystalline lens extraction may significantly modify the chromatic aberration of the pseudophakic eye. Chromatic aberrations are inducing vision losses due sharpness reduction of any object edges. The contrast sensitivity as much as the visual acuity are then reduced. This has been proven with measurements optical benches. Diffractive and refractive effects act in an opposite way and can in principle be compensated. However rules to creates an achromatic lens based on refractive-diffractive lens are quite complex because topology, dioptry , abbe number,… In this study, we will investigate the effect of wavelength on the through-focus modulation transfer function (MTF) and diffraction efficiency for different pupil apertures and different diffractive intraocular lenses. Pin-hole effect will also be discussed and addressed with the point of view of chromatic effect. [less ▲]

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See detailThe Far Ultra-Violet Imager on the Icon Mission
Mende, Stephen; Frey, Harald; Rider, Kodi et al

in Space Science Reviews (2017)

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ ionosphere. During sunlit atmospheric ... [more ▼]

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far Ultra- Violet (FUV) imager is a Czerny–Turner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft. [less ▲]

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See detailCalibration and testing of wide-field UV instruments
Frey, Harald; Mende, Stephen; Loicq, Jerôme ULiege et al

in Journal of Geophysical Research. Space Physics (2017), 122

As with all optical systems the calibration of wide-field ultraviolet (UV) systems includes three main areas: sensitivity, imaging quality, and imaging capability. The one thing that makes UV calibrations ... [more ▼]

As with all optical systems the calibration of wide-field ultraviolet (UV) systems includes three main areas: sensitivity, imaging quality, and imaging capability. The one thing that makes UV calibrations difficult is the need for working in vacuum substantially extending the required time and effort compared to visible systems. In theory a ray tracing and characterization of each individual component of the optical system (mirrors, windows, and grating) should provide the transmission efficiency of the combined system. However, potentially unknown effects (contamination, misalignment, and measurement errors) can make the final error too large and unacceptable for most applications. Therefore, it is desirable to test and measure the optical properties of the whole system in vacuum and compare the overall response to the response of a calibrated photon detector. A proper comparison then allows the quantification of individual sources of uncertainty and ensures that the whole instrument performance is within acceptable tolerances or pinpoints which parts fail to meet requirements. Based on the experience with the IMAGE Spectrographic Imager, the Wide-band Imaging Camera, and the ICON Far Ultraviolet instruments, we discuss the steps and procedures for the proper radiometric sensitivity and passband calibration, spot size, imaging distortions, flatfield, and field of view determination. [less ▲]

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See detailInverse opal photoanodes: preparation and optical properties
Dewalque, Jennifer ULiege; Spronck, Gilles ULiege; Baron, Damien ULiege et al

Conference (2017, March 01)

Perovskite compounds, used either in mesoscopic or planar solar cells, have allowed preparing highly efficient solid-state devices (>20%). In this study, we propose to design photoanodes with photonic ... [more ▼]

Perovskite compounds, used either in mesoscopic or planar solar cells, have allowed preparing highly efficient solid-state devices (>20%). In this study, we propose to design photoanodes with photonic structure in order to modulate light interaction. The periodic structure of porosity could add specific optical properties likely to increase light harvesting and reduce reflexion losses. Besides, current efficiencies reported for mesoscopic perovskite solar cells using an inorganic porous scaffold are slightly lower than those reported for planar perovskite cells mainly due to issues in perovskite infiltration. The control of the porous network architecture in terms of pore organization, size and connectivity could overcome this limitation. TiO2/perovskite and perovskite-only photoanodes with an inverse opal porous structure are prepared from templating techniques, using polystyrene beads as structuring agent. The photoanode microstructure is further characterized by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). In parallel, light interaction is modeled in order to find the best compromise in terms of photonic architecture (pore size, organization, thickness…). [less ▲]

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See detailPhotonic photoanode for macroporous perovskite solar cells
Baron, Damien ULiege; Dewalque, Jennifer ULiege; Henrist, Catherine ULiege et al

Poster (2017, March 01)

Organic-inorganic metal halide perovskite solar cells (PSCs) have reached power conversion efficiencies over 20%. Two archetypal PSC architectures are reported in the literature: mesoporous and planar ... [more ▼]

Organic-inorganic metal halide perovskite solar cells (PSCs) have reached power conversion efficiencies over 20%. Two archetypal PSC architectures are reported in the literature: mesoporous and planar PSCs. In the former one, a mesoporous TiO2 scaffold is incorporated into the cell. Because sizes of the mesopores are typically small compared to wavelengths of visible light, the scaffold barely scatters light. In this work, we propose to periodically structure a porous TiO2 scaffold incorporating pores with diameters comparable to wavelengths of visible light thanks to the use of colloidal crystal templating fabrication method. The resulting TiO2 scaffold filled with perovskite will constitute an opal-like photonic crystal incorporated in the solar cell, which will strongly interact with light. Through Finite Difference Time Domain (FDTD) simulations, we demonstrate that the photonic crystal induces resonances that can be exploited to modulate light harvesting in the macroporous TiO2 layer. Sunlight absorption by the PSC will be presented and discussed with dependency of pore sizes and number of opal layers. [less ▲]

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See detailConception of a near-infrared spectrometer for ground-based observations of massive stars
Kintziger, Christian ULiege; Desselle, Richard ULiege; Loicq, Jerôme ULiege et al

in Journal of Astronomical Telescopes, Instruments, and Systems (2017), 3(1), 015002

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument for stellar astrophysics. Starting from the derivation of theoretical relationships from the ... [more ▼]

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument for stellar astrophysics. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s efficiency. Then the verification of predicted optical performances is investigated through optical analyses, such as resolution checking. [less ▲]

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See detailTRIFOCAL INTRAOCULAR LENS WITH EXTENDED RANGE OF VISION AND CORRECTION OF LONGITUDINAL CHROMATIC ABERRATION
Pagnoulle, Christophe; Redzovic, Suad; Voisin, Laure et al

Patent (2017)

The present invention relates to an intraocular lens, and in particular to an intraocular lens with three focal points and a diffractive profile on an anterior or posterior face. This lens provides ... [more ▼]

The present invention relates to an intraocular lens, and in particular to an intraocular lens with three focal points and a diffractive profile on an anterior or posterior face. This lens provides extended range of vision (EROV) from far to near distance and reduces linear chromatic aberration (LCA). [less ▲]

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See detailWaveguide solar concentrator design with spectrally separated light
Michel, Céline ULiege; Blain, Pascal ULiege; Clermont, Lionel ULiege et al

in Solar Energy (2017), 157

In this article, we propose a new solar concentrator based on spectral splitting of sunlight. Spectral splitting has the objective to collect different spectra onto spectrally adapted solar cells for a ... [more ▼]

In this article, we propose a new solar concentrator based on spectral splitting of sunlight. Spectral splitting has the objective to collect different spectra onto spectrally adapted solar cells for a more efficient use of the Sun’s spectrum. Its combination with solar concentration makes an alternative to classical technologies. The proposed concentrator is composed of a diffractive/refractive optical element that spectrally splits and focuses the light onto a waveguide. The light is then conducted by total internal reflection towards the two specific solar cells. The optical concept and optimization of each element is presented in this paper. An adaptation for dye sensitized solar cells is performed. A geometrical factor around 5× is reached. Finally, theoretical optical efficiency, the manufacturing process and experimental testing with a collimated Sun simulator are presented. [less ▲]

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See detailClinically relevant optical properties of three types of intraocular lenses
Gatinel, Damien; Loicq, Jerôme ULiege

Conference (2016, September)

Purpose: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus (TECNIS Symfony), bifocal (TECNIS ZMB00), and trifocal ... [more ▼]

Purpose: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus (TECNIS Symfony), bifocal (TECNIS ZMB00), and trifocal (FineVision GFree). Setting: Rothschild Foundation Paris, France - Liege Space Center Liège, Belgique Methods: Surface topography was analyzed by optical microscopy. Modulation transfer function (MTF) and spherical aberrations were determined on optical bench for variable pupil apertures and with two cornea models (0 µm and +0.28 µm). United States Air Force target imaging was analyzed for different focal points (near, intermediate, and far). Point spread function (PSF) and halos were quantified and compared. Results: All lenses presented step-like optic topography. For a pupil size of = 3 mm, distinctive MTF peaks were observed for all lenses: two peaks for the extended depth of focus and bifocal lenses with +1.75 and +4.00 diopters (D) addition, respectively, and three peaks for the trifocal lens with +1.75 and +3.50 addition for intermediate and near vision, respectively. The extended depth of focus and bifocal lens had slightly higher MTF at best focus with the +0.28 µm cornea model than with the 0 µm model, whereas the trifocal lens was likely to be more independent of the corneal spherical aberrations. Conclusions: Each lens appears to rely on light diffraction for optical performance, presenting halos with comparable intensities. For small pupil apertures, the MTF peaks for the far and intermediate focal distances of the trifocal and extended depth of focus lenses overlap, but the trifocal lens presented an additional MTF peak for the near focal points. [less ▲]

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See detailRefractive and diffractive contribution of linear chromatic aberration (LCA) on depth-of-focus with trifocal intraocular lenses (IOLs)
Loicq, Jerôme ULiege; Gatinel, Damien

Poster (2016, September)

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation ... [more ▼]

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation Ophtalmologique A. de Rothschild, Paris Methods: The LCAs associated with the three focal points of hydrophobic and hydrophilic diffractive FineVision trifocal IOLs (PhysIOL SA, Liège, Belgium), were simulated in an Arizona eye model and experimentally measured on an optical bench at 480, 546 and 650 nm. The effect of Abbe number and aperture on different IOL materials was also evaluated. Based on wavelength–dependent MTF through-focus curves and PSF properties, polychromatic behavior of the trifocal IOLs was assessed under mesopic and photopic conditions. Results: LCA amplitude and sign were different for each of the trifocal IOL focal points. The diffractive LCA for near and intermediate was independent of IOL material (GFree versus hydrophilic acrylic, 26%), while far vision LCA appeared to be controlled by the material Abbe number. Under polychromatic conditions, the LCA contributed to depth of focus extension with different types of lens material, providing maximal visual acuity under white light conditions at all distances. Conclusions: Diffractive trifocal IOLs show chromatic aberrations with an increase in depth of focus under polychromatic light. This effect likely contributes to the extended range of vision. [less ▲]

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See detailConception of a near-IR spectrometer for ground-based observations of massive stars
Kintziger, Christian ULiege; Desselle, Richard ULiege; Loicq, Jerôme ULiege et al

in Proc. SPIE Volume 9908 Ground-based and Airborne Instrumentation for Astronomy VI (2016, August 09)

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships ... [more ▼]

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s performances. Then, the verification of predicted optical performances is investigated through optical analyses such as resolution checking. Eventually, the star positioning system onto the central fiber core is explained. [less ▲]

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See detailConception of a near-IR spectrometer for ground-based observations of massive stars
Kintziger, Christian ULiege; Desselle, Richard ULiege; Loicq, Jerôme ULiege et al

Poster (2016, June 27)

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships ... [more ▼]

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s performances. Then, the verification of predicted optical performances is investigated through optical analyses such as resolution checking. Eventually, the star positioning system onto the central fiber core is explained. [less ▲]

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See detailOptical design and optical properties of a VUV spectrographic imager for ICON mission
Loicq, Jerôme ULiege; Kintziger, Christian ULiege; Mazzoli, Alexandra ULiege et al

in Proceedings of SPIE (2016, June)

In the frame of the ICON (Ionospheric Connection Explorer) mission of NASA led by UC Berkeley, CSL and SSL Berkeley have designed in cooperation a new Far UV spectro-imager. The instrument is based on a ... [more ▼]

In the frame of the ICON (Ionospheric Connection Explorer) mission of NASA led by UC Berkeley, CSL and SSL Berkeley have designed in cooperation a new Far UV spectro-imager. The instrument is based on a Czerny-Turner spectrograph coupled with two back imagers. The whole field of view covers [± 12° vertical, ± 9° horizontal]. The instrument is surmounted by a rotating mirror to adjust the horizontal field of view pointing by ± 30°. To meet the scientific imaging and spectral requirements the instrument has been optimized. The optimization philosophy and related analysis are presented in the present paper. PSF, distortion map and spectral properties are described. A tolerance study and alignment cases were performed to prove the instrument can be built and aligned. Finally straylight and out of band properties are discussed. [less ▲]

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See detailAlignment and calibration of the ICON-FUV instrument: Development of a vacuum UV facility
Loicq, Jerôme ULiege; Blain, Pascal ULiege; Kintziger, Christian ULiege et al

in Proceedings of SPIE (2016, June)

The optical calibration of the ICON-FUV instrument requires designing specific ground support equipment (GSE). The ICON-FUV instrument is a spectrographic imager that operates on two specific wavelengths ... [more ▼]

The optical calibration of the ICON-FUV instrument requires designing specific ground support equipment (GSE). The ICON-FUV instrument is a spectrographic imager that operates on two specific wavelengths in the UV (135.6 nm and 157 nm). All the operations have to be performed under vacuum UV light. The optical setup is based on a VUV monochromator coupled with a collimator that illuminates the FUV entrance slit. The instrument is placed on a manipulator providing fields pointing. Image quality and spectral properties can be then characterized for each field. OGSE, MGSE, optical calibration plan and vacuum alignment of the instrument are described. [less ▲]

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See detailVUV Optical Ground System Equipment and its application to the ICON FUV flight grating characterization and selection
Blain, Pascal ULiege; Desselle, Richard ULiege; Domken, Isabelle ULiege et al

in Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation (2016, June)

ICON FUV is a two channel spectrographic imager that measures intensity and spatial distribution of oxygen (135.6 nm) and molecular nitrogen (157 nm) of the ionosphere. As those wavelengths are strongly ... [more ▼]

ICON FUV is a two channel spectrographic imager that measures intensity and spatial distribution of oxygen (135.6 nm) and molecular nitrogen (157 nm) of the ionosphere. As those wavelengths are strongly absorbed by the atmosphere, the optical elements of the system have to be tested inside vacuum chambers. Prior to the instrument alignment and calibration, two 3600 gr/mm gratings were characterized. The primary focus is the measurement of the diffraction efficiencies; while the second objective is to select the best grating and to define which is the flight and the spare. A dedicated setup has been developed to assess the grating optical performances under vacuum. A 1 cm diameter collimated beam is generated using an off-axis parabola and a UV source at its focal point. The grating is placed at the center of two rotation stages collinearly aligned. One detector is placed on a rotating arm, deported from its rotation center. A PMT detector records diffracted light intensity with respect to its angular position and its wavelength. Angular incidence on the grating is tuned with the help of the second rotation stage. The grating efficiency homogeneity and scattering properties are measured through a Y-X scan. [less ▲]

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See detailComparison of 3 Diffractive IOLs in 3 Wavelengths Bifocal/ EDOF/Trifocal.
Gatinel, Damien; Pagnoulle, Christophe; Loicq, Jerôme ULiege et al

Conference (2016, May)

Purpose To describe the optical performances of 3 types of diffractive hydrophobic intraocular lenses (IOLs): monofocal achromatic, bifocal and trifocal, using various visible wavelengths. Methods 3 IOLs ... [more ▼]

Purpose To describe the optical performances of 3 types of diffractive hydrophobic intraocular lenses (IOLs): monofocal achromatic, bifocal and trifocal, using various visible wavelengths. Methods 3 IOLs were measured with an optical bench (PMTF,LambdaX,Nivelles, Belgium) to determine modulation transfer function (MTF) and point spread function (PSF). Measurements were performed at 480 nm,546 nm,650 nm using an aberration free cornea and aspheric artificial cornea generating +0.28µm positive spherical aberration by ISO11979-2 guidelines. Through-focus MTF was recorded for various pupil apertures. Evaluation of halos was performed from PSF measurements obtained at each focal spot location. Images of USAF targets were recorded with simulated distances from 1m to 25cm. Amplitude of off-axis peaks of radial profile of PSF enabled to quantify percentage of energy within the halos. Results The monofocal and the bifocal IOLs presented 2 peaks on the through-focus MTF in green light: intermediate vision (at +1.75D) for the monofocal achromatic lens, and far and near vision (at +4D) for the bifocal IOL of the same material. Three peaks (Distance, Intermediate at +1.75D, Near at +3.5D) were recorded with the trifocal IOL at any wavelength. The achromatic monofocal IOL was monofocal for far vision with red light and monofocal for near vision with blue light. The influence of the cornea models was limited. The amount of halos were comparable between lenses (3 to 5 % of the enclosed central light energy). Conclusion The achromatic diffractive IOL behaved like a bifocal IOL with an intermediate addition foci in green light. The bifocal and trifocal IOL induced similar chromatic effects for the near (bifocal, trifocal) and intermediate (trifocal) foci. [less ▲]

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See detailClinically Relevant Optical Properties of Bifocal, Trifocal, and Extended Depth of Focus Intraocular Lenses
Gatinel, Damien; Loicq, Jerôme ULiege

in Journal of Refractive Surgery (2016), 32(4), 273-280

PURPOSE: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus, bifocal, and trifocal. METHODS: The tested IOLs were: TECNIS ... [more ▼]

PURPOSE: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus, bifocal, and trifocal. METHODS: The tested IOLs were: TECNIS ZMB00 (bifocal; Abbott Medical Optics, Abbott Park, IL), TECNIS Symfony ZXR00 (extended depth of focus; Abbott Medical Optics), and FineVision GFree hydrophobic (trifocal; PhysIOL, Liège, Belgium). Their surface topography was analyzed by optical microscopy. Modulation transfer function (MTF) and spherical aberrations were determined on optical bench for variable pupil apertures and with two cornea models (0 μm and +0.28 μm). United States Air Force target imaging was analyzed for different focal points (near, intermediate, and far). Point spread function (PSF) and halos were quantified and compared. RESULTS: The three lenses presented step-like optic topography. For a pupil size of 3 mm or greater, clearly distinctive MTF peaks were observed for all lenses: two peaks for the extended depth of focus and bifocal lenses with +1.75 and +4.00 diopters (D) addition, respectively, and three peaks for the trifocal lens with +1.75 and +3.50 addition for intermediate and near vision, respectively. The extended depth of focus and bifocal lens had slightly higher MTF at best focus with the +0.28 μm cornea model than with the 0 μm model, whereas the trifocal lens was likely to be more independent of the corneal spherical aberrations.CONCLUSIONS: It appears that the three lenses rely on light diffraction for their optical performance, presenting halos with comparable intensities. For small pupil apertures (< 3 mm), the MTF peaks for the far and intermediate focal distances of the trifocal and extended depth of focus lenses overlap, but the trifocal lens presented an additional MTF peak for the near focal points. [less ▲]

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See detailComparison of 3 diffractive IOLs: one monofocal (achromatic), one bifocal and one trifocal lens implant
Gatinel, Damien; Loicq, Jerôme ULiege; Pagnoule, Christophe et al

Conference (2015, September 08)

Purpose: To describe the optical performance of 3 types (monofocal, bifocal and trifocal) of diffractive hydrophobic intraocular lenses (IOLs). Setting: Fondation Rothschild, Paris, France Methods: An ... [more ▼]

Purpose: To describe the optical performance of 3 types (monofocal, bifocal and trifocal) of diffractive hydrophobic intraocular lenses (IOLs). Setting: Fondation Rothschild, Paris, France Methods: An achromatic monofocal, a bifocal and trifocal diffractive IOLs were measured with an optical bench, designed to measure Modulation transfer function (MTF) and point spread function (PSF) of diffractive intraocular lenses. The measurements were performed at 3 wavelengths (480 nm, 546 nm and 650 nm), using an aberration free cornea and an aspherical artificial cornea generating a +0.28 µm of positive spherical aberration (ISO 11979-2 guideline). The through-focus MTF was recorded with the 3 IOLs for various pupil apertures. The evaluation of the magnitude of the halos was performed from PSF measurement obtained at each focal spot location. Results: The monofocal and the two bifocal IOLs were presenting 2 peaks on the through-focus MTF in the green: for intermediate vision (at 1.75D) for the monofocal achromatic lens, and for far and for near vision( at +4D) for the bifocal IOL of the same material. Three peaks were recorded with the trifocal IOL at any wavelength. The achromatic monofocal was monofocal for far in the red and monofocal for near in the blue. The amount of energy allocated to each focal point was not very different for the three IOLs except for smaller apertures where the distance vision with the trifocal IOL had a significant lower peak than the two other IOLs. The amount of halos were comparable between lenses. Conclusions: The diffractive and refractive optics generated opposite chromatic aberration. A achromatic diffractive IOL behaves like a bifocal IOL with an intermediate addition The bifocal and trifocal IOL induce similar chromatic effects for the near (bifocal, trifocal) and intermediate (trifocal) foci. The tested diffractive patterns wee not efficient to correct the chromatic aberration at the distance foci for all tested IOLs. [less ▲]

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See detailProperties of a new hydrophobic diffractive trifocal intraocular lens: linear chromatic aberrations (LCA) by optical simulation and optical bench testing
Loicq, Jerôme ULiege; Gatinel, Damien

Conference (2015, September 08)

Purpose: Impact of the IOL raw material Abbe number on diffractive trifocal optical outcomes in terms of light energy partition between the three foci, modulation transfer function (MTF) and linear ... [more ▼]

Purpose: Impact of the IOL raw material Abbe number on diffractive trifocal optical outcomes in terms of light energy partition between the three foci, modulation transfer function (MTF) and linear chromatic aberration (LCA). Setting: Space Center Liège (Centre Spatial de Liège), University of Liège, Liège, Belgium Methods: The difference between hydrophilic and hydrophobic materials doesn't rely on biocompatibility only, but also influence some optical properties. In order to highlight the impact of the raw material associated to Diffractive-Trifocal-IOLs, we compare certain optical properties of two Diffractive-Trifocal-IOLs associated to Physiol's Trifocal-technology and made of 26% hydrophilic and hydrophobic GF raw material. The Abbe number of the two IOL materials was measured with a refractometer. The through focus MTF curves at 3 wavelengths (480, 546 and 650 nm) and different apertures were generated by simulation in an Arizona eye model and compared with results on a PMTF optical bench. Results: The through focus MTF curves at the three wavelengths shows that the diffracted light for the near vision (+3.5 D) by the trifocal optic generates chromatic aberrations of opposite sign with respect to the refracted light assigned to the Far vision. The diffracted light at the origin of the Intermediate vision (+1.75 D) does not show significant amount of LCA and can be considered as a chromatic aberration free focus. Results are similar for the two lens materials. Conclusions: Diffractive Trifocal IOLs show chromatic aberrations whose sign and amplitude depend on the add-power of the different foci (far, near or intermediate), but is basically independent of the nature of the type of raw material, hydrophilic or hydrophobic. [less ▲]

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