Modulation Transfer Function Values Research Articles

Optical tolerance to rotation of trifocal toric intraocular lenses as a function of the cylinder power.

The aim was to assess the impact of 5- and 10-degree rotations in the optical quality of a trifocal toric intraocular lens with different amounts of cylinder. Two Physiol Toric intraocular lenses with 1.5 and 3.0 D of cylinder were analysed in three different positions: centred, 5 and 10 degrees rotated. The optical quality of the intraocular lenses was evaluated with the PMTF optical bench through specific perpendicular targets. The analysis was performed by the through-focus modulation transfer function curves and the modulation transfer function corresponding to distance vision (0 D of vergence). For a centred situation, the through-focus modulation transfer function curves of both intraocular lenses showed the classical three peaks corresponding to the powers of the two principal meridians of the intraocular lenses. When 5 and 10 degrees of rotation were induced, the three peaks were attenuated in both cases. The case with the intraocular lens with 3.0 D of cylinder and 10 degrees of rotation showed the worst optical quality and a significant loss of trifocality. The modulation transfer function values obtained for distance vision also showed the worst optical quality for the intraocular lens with 3.0 D of cylinder and 10 degrees of rotation. Rotations over 5 degrees decreased the optical quality of trifocal toric intraocular lenses, being this reduction moderate from 5 to 10 degrees for low levels of cylinder (≤1.5 D). For mid-high levels of cylinder (≥3.0 D), rotations over 5 degrees cause a significant loss of optical quality at all object distances.

Optical design and simulation of an integrated OCT and video rigid laryngoscope

An integrated optical coherence tomography (OCT) and video rigid laryngoscope have been designed to acquire surface and subsurface tissue images of larynx simultaneously. The dual-modality system that is based on a common-path design with components as few as possible effectively maintains the light transmittance without compromising the imaging quality. In this paper, the field of view (FOV) of the system can reach [Formula: see text] by use of a gradient index (GRIN) lens as the relay element and a four-lens group as the distal objective, respectively. The simulation showed that the modulation transfer function (MTF) value in each FOV of the rigid video endoscope at 160[Formula: see text]lp/mm is greater than 0.1 while the root mean square (RMS) radii of the OCT beam in the center and edge of the FOV are 14.948[Formula: see text][Formula: see text]m and 73.609[Formula: see text][Formula: see text]m, respectively. The resolutions of both OCT and video endoscope meet the requirement of clinical application. In addition, all the components of the system are spherical, therefore the system can be of low cost and easy to assemble.

Integrating optical design with Taguchi method in a remote wireless light charging system

Power cannot be efficiently transmitted over long distances using conventional wireless transmission. Although increasing charger power effectively improves charging efficiency, safety concerns include mobile phone heating, long-term health damage caused by electromagnetic waves, and interferences on other precise instruments. This study proposed a remote wireless charging system that utilizes mechanical movement design in zoom lenses to maintain wireless charging system performance and perform charging operations from different positions in a room through the movement between lens groups. Moreover, the Taguchi method was applied in optical design software to identify the optimal factors for performance improvement. The wireless light charging system was optimized using the Taguchi method. In addition, optimization of curvature, thickness, and material were proposed. Three focal lengths were optimized through 18 sets of experimental data to reduce the spherical and comatic aberrations; and modulation transfer function value was improved to enhance the performance of the remote wireless light charging system. The remote wireless light charging system was designed to be used in an indoor space. In general, the system is installed on the ceiling, and mechanical movement function is enabled for the lens. Moving the lens changes the focus of the system. This allows the charging light source to change its original light path and generate a new focal point. The system features three zoom positions: 3 m from the ceiling to the floor, 2 m from the ceiling to the desktop, and 1.5 m from the ceiling to a person standing with a mobile phone. This allows the wireless light charging system to focus on the mobile phone receiver for charging in every corner within the indoor space. The wireless charging system features three focal lengths; the field of view (FOV) values are 0°, 24°, and 34°; the total length of the system is 635.45 mm; and the size of the spot diagram is 20% at various FOV angles at a spatial frequency of 80 lp/mm; and the lateral color was < ± 2 μm. A photodiode with an area of 12.0 mm was used as the receiver, and energy could be effectively received when the spot size was greater than or equal to the receiving area.

Comparative Analysis of Visual Performance and Optical Quality with a Rotationally Asymmetric Multifocal Intraocular Lens and an Apodized Diffractive Multifocal Intraocular Lens.

Purpose To compare the short-term visual outcomes and intraocular optical performance of a rotationally asymmetric multifocal intraocular lens (MIOL) (SBL-3, Lenstec, Inc., Christ Church, Barbados) and an apodized diffractive MIOL (the Acrysof IQ ResTOR SN6AD1, Alcon Laboratories, Inc., Fort Worth, Texas, United States). Methods A prospective, comparative, nonrandomized, and single-center study. Sixty-eight age-related cataract patients (81 eyes) after phacoemulsification cataract surgery and in-the-bag MIOL implantation were enrolled. Thirty-eight eyes received SBL-3, and 43 eyes received SN6AD1. Ophthalmological evaluation included uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), modulation transfer function (MTF), Strehl ratio (SR), intraocular aberrations (4 mm optical zone), and defocus curve at 3 months postoperatively. The Chinese version of the visual function index-14 (VF-12-CN) and spectacle independence were assessed in all patients. Results There was no statistically significant difference between groups in postoperative UDVA (p = 0.186). Postoperative UIVA and UNVA were significantly better for the SBL-3 group than for the SN6AD1 group (p < 0.01). Statistically significant differences were revealed in defocus levels from –3.50 D to −4.00 D with better visual acuities for the SBL-3 group (p < 0.01). For intraocular optical quality outcomes, statistically significant differences between groups were observed in RMS of intraocular total aberrations, coma, and trefoil high-order aberrations, presenting significantly higher values of these parameters in the eyes of the SBL-3 group (p < 0.01). Statistically significant differences were revealed in the MTF values at spatial frequencies of 5 and 10 cycles/degree between groups. There were no significant differences in scores of VF-12-CN, and spectacle independence between the groups (p > 0.05). Conclusions Both MIOLs were able to successfully restore visual function after cataract surgery. SBL-3 provided better UIVA and UNVA with a wider range of intermediate vision.

Laboratory evaluation of the optical properties of two extended-depth-of-focus intraocular lenses

BackgroundTo experimentally compare the optical performance of two different Extended-Depth-of-Focus (EDOF) intraocular lenses (IOLs) using a standardized optical bench set-up.MethodsIn this experimental study, following IOLs were assessed: the TECNIS® Symfony ZXR00 (Johnson&Johnson, Santa Ana, USA) and the AT LARA 829MP (Carl Zeiss Meditec, Jena, Germany) IOLs. The through-focus modulation transfer function (MTF) values were measured at a spatial frequency of 50 lp/mm and at aperture sizes of 2, 3, and 4.5 mm. Each IOL was measured while centered using ISO 11979-2 Model 1 (aberration-free) and Model 2 (+ 0.28 μm spherical aberration) corneas. United States Air Force (USAF) target images were also recorded for a qualitative evaluation.ResultsAt 2 mm pupil with ISO1 cornea, the primary and secondary foci of both IOLs appeared to merge, providing an elongated depth of focus. At 3 and 4.5 mm pupil sizes, the through-focus MTF curves of both IOLs showed a bifocal-like V-pattern. While the Symfony IOL showed an overall superior MTF values when measured with the ISO2 cornea, the opposite propensity could be observed with the AT LARA IOL. This optical behavior could be qualitatively confirmed by the USAF target images.ConclusionsAlthough the two EDOF IOLs share similarities in their optical properties, the main difference lies in their optical design and performance with respect to spherical aberration. Such characteristics should be taken into account during IOL and patient selection.

Multi-frame motion deblurring using coded exposure imaging with complementary fluttering sequences

Motion blurring is one of the most common but unpleasant phenomenons along with the camera imaging process, resulting in image resolution degradation. Coded exposure technique is an effective computational imaging approach to handle with this problem by introducing extra shutter control within the exposure time and help the deblurring problem become well-posed. In this paper, a multi-frame motion deblurring framework is presented using coded exposure imaging with complementary fluttering sequences. A set of complementary sequences are well designed to compensate for the spatial losses due to motion blurring in each frame based on the complementary theory of Golay matrix pair. Hadamard matrix is served as the Golay sequence pair to generate complementary fluttering sequences to capture multi-frame images for the following deblurring processing. The joint modulation transfer function (MTF) of the complementary code sequences has a more flat spectrum curve with smaller variance value and higher MTF value. For multi-frame deblurring implementation, a unified multi-image deblurring framework is performed by introducing Total Variation (TV) regularization prior with each selected code sequence in the complementary set integrated in the energy function. A real imaging system is built and various groups of synthetic and real-world imaging experiments are carried out to verify the effectiveness of the method. Experimental results demonstrate that the deblurrring images obtained by the proposed approach are of high quality with improved objective image evaluation values and better negative artifacts suppression.

Ray propagation imaging and optical quality evaluation of different intraocular lens models.

PurposeRay propagation visualization and optical performance analysis of four different intraocular lenses (IOLs)MethodsIn this laboratory study, four IOLs with different optical designs were assessed: a monofocal AcrySof IQ SN60WF [Alcon], a diffractive-refractive bifocal AcrySof IQ Restor SN6AD1 [Alcon], a diffractive trifocal AcrySof IQ PanOptix TFNT00 [Alcon], and a diffractive extended-depth-of-focus (EDOF) Symfony ZXR00 [Johnson&Johnson]. An experimental set-up with a water bath containing 0.01% fluorescein solution and monochromatic green laser light (532 nm) was used to visualize the propagation of light rays. Also, the optical performance of the IOLs was evaluated by measuring the modulation transfer function (MTF) values at a pupil sizes of 3.0 and 4.5 mm on the optical bench OptiSpheric® IOL PRO II (Trioptics GmbH, Germany).ResultsBoth the diffractive-refractive bifocal IOL and the EDOF IOL showed two defined foci for distance and near vision. In the diffractive trifocal IOL, three distinct foci for distance, intermediate, and near vision could be visualized.ConclusionsThe ray propagation visualization technique allows a qualitative assessment and comparison of light energy distribution between different IOL models. The measured Through-Focus Response (TFR) quantitatively confirmed the evaluated ray propagation behavior.

Comparison of optical quality and distinct macular thickness in femtosecond laser-assisted versus phacoemulsification cataract surgery

BackgroundOptical quality and macular thickness changing optical quality is rarely reported after femtosecond laser-assisted cataract surgery (FLACS). In current research, we evaluated optical quality recovery and distinct macular thickness changes after FLACS and phacoemulsification cataract surgery (PCS).MethodsA total of 100 cataract patients (100 eyes) were included (50 eyes for the FLACS group and 50 eyes for the PCS group). Modulation transfer function (MTF), point spread function (PSF) and dysfunctional lens index (DLI) were measured by a ray-tracing aberrometer (iTrace). Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were also assessed pre-operation,1 week and 1 month after surgery. The MTF values at spatial frequencies of 5, 10, 15, 20, 25 and 30 cycles/degree (c/d) were selected. We used optical coherence tomography (OCT) to assess the macular thickness of different regions pre-operatively and1month after the surgery.ResultsIn PCS group, we found the statistically significant differences between pre-operation and post-operation in DLI (p < 0.0001), PSF (strehl ratio, SR) (p = 0.027) and MTF (p = 0.028), but not intraocular pressure (IOP) (p = 0.857). The differences between pre-operation and post-operation for DLI (p = 0.031), SR (p = 0.01) and IOP (p = 0.03), but not MTF (p = 0.128) were also found in FLACS group. The differences were statistically significant when the spatial frequencies were at 5, 10 and 25 (p = 0.013, 0.031 and 0.048) between pre-operation and post-operation in PCS group but not FLACS group at 1 month. In PCS group, we found the differences between pre-operation and post-operation in nasal inter macular ring thickness (NIMRT) (p = 0.03), foveal volume (FV) (p = 0.034) and average retinal thickness (ART) (p = 0.025) but not FLACS group at 1 month.ConclusionFLACS is safe that did not cause significant increase of macular thickness in current study. However, it also cannot produce better optical quality. In contrast, PCS can produce macular thickness changes, but better optical quality recovery. The slightly retinal change may not affect optical quality.

Experimental demonstration of wave-front coded imaging with a very low response of the modulation transfer function at the Nyquist frequency.

Wave-front coding (WFC) is a well-known technique that can be used to extend the depth of field (DOF) of incoherent imaging systems. The phase masks make the optical transfer function drop significantly, and digital restoration must be used to obtain a clear image with a largely extended DOF. According to the existing literature, in order to obtain satisfactory restoration results, the optical modulation transfer function (MTF) at the Nyquist frequency is required to be bigger than 0.1, which has already become a popularly accepted design constraint. However, according to our experimental research reported in this paper, this requirement is overly strict. By assembling one already fabricated WFC lens and another camera having physically higher resolution, the MTF of the newly assembled WFC system used in the experimentation has quite a low response at its Nyquist frequency. The experimental results demonstrate that when the optical MTF value at the Nyquist frequency reaches the minimum value of about 0.05, visually satisfactory restoration results can still be obtained as long as the MTF is optimized to be highly insensitive to defocus and the corresponding SNR of the coded intermediate images goes beyond 20 dB at the same time. The experimental results indicate that the overly strict constraint could be alleviated while designing a WFC system.

Underwater superoleophobic and anti-oil microlens array prepared by combing femtosecond laser wet etching and direct writing techniques.

As an important micro-optical device, microlens array (MLA) also has broad applications in aqueous environment apart from atmosphere, such as bioscience research, ocean exploration, and microfluidic systems. However, the surface of the normal MLA is easily polluted by oil contaminations when the MLA is practically applied in a water medium, leading to the loss of its optical imaging ability. Herein, we fabricated a functional MLA with underwater anti-oil and self-cleaning abilities by combining the femtosecond laser wet etching (FLWE) and the femtosecond laser direct writing (FLDW) techniques. The as-prepared close-packed MLA is composed of 10000 single microlenses with the aperture diameter of 50 µm. The surface of each microlens is further textured with micro/nanoparticles. Clear and uniform images could be captured by using the resultant MLA in water, demonstrating great underwater imaging ability. The modulation transfer function value is larger than 0.6 at 55 lp/mm. In addition, the micro/nanostructures endow the as-fabricated MLA surface with underwater superoleophobicity and oil-repellent performance. Various oils can be repelled by the resultant MLA in water. Underwater 1,2-dichloroethane oil droplet on the textured MLA has a contact angle of 158.0 ± 0.5° and a sliding angle of 2.0 ± 0.2°. The underwater superoleophobic MLA also has good mechanical durability. The anti-oil and self-cleaning functions will broaden the applications of the MLA in ocean exploration, bioscience research, microfluidic system, and many underwater MLA-based systems.

High-speed slot-scanning radiography using small-angle tomosynthesis: Investigation of spatial resolution.

This paper studies spatial resolution that is achievable with a fast slot-scanning tomosynthesis approach for orthopedic examinations. Hereby, we use parallel scanning motion implemented in a twin robotic x-ray system. We have measured and analyzed the modulation transfer function (MTF) for various combinations of scanning speed, x-ray tube voltage, pulse length, the nominal focal spot size as well as source-to-object distances. Moreover, we present a theoretical model which describes the system in terms of the MTF. The system was equipped with newly developed linear trajectory prototypes for slot scanning. The acquired images form the basis for a small-angle tomosynthesis reconstruction. In total, three different scanning speeds (27, 14, 8cm/s), pulse lengths (1, 2, 4ms), tube voltages (80, 100, 120kV), two nominal focal spot sizes (0.6, 1.0), and three source-to-object distances (950, 1050, 1150mm) were investigated. To determine the resolution capabilities, we measured the MTF for the given parameter space. The results were then used to design a filter that yields a desired resolution in the reconstructed image. In addition, we also measured the noise power spectrum (NPS) to show the influence of the aforementioned filters on the noise distribution. We have shown that the presented model is in good agreement with the performed measurements. Scanning speed and pulse width have an impact on the MTF in the scanning direction. Up to a travel distance of 0.3mm during an x-ray pulse, an isotropic resolution can be achieved. Longer pulse width or higher scanning speed cause anisotropic resolution. Moreover, it is shown that none of the investigated parameters have an influence on the MTF perpendicular to the scanning direction (slot direction). The 10% MTF value ranges between 9 and 18lp/cm in the scanning direction and about 18lp/cm in slot direction. Tube voltage, nominal focal spot size as well as the source-to-object distance showed no major impact on the system MTF. In terms of the anisotropic resolution capabilities, we have shown that limiting the resolution in the slot direction to obtain isotropic resolution is possible yet at the cost of an inhomogeneous noise pattern. However, maintaining the resolution in slot direction will provide a better edge response and a more homogeneous noise texture at the cost of an inhomogeneous image resolution. We have demonstrated the feasibility of the slot-scanning technique using a twin-robotic x-ray system. Even the fastest scanning mode (27cm/s) yields image resolution on a level that is sufficient for typical orthopedic examinations in terms of musculoskeletal (MSK) measurements. Moreover, it could be shown that the application of specifically designed target MTFs on two-dimensional x-ray images is feasible.

Spatial Distortion Assessments of a Low-Cost Laboratory and Field Hyperspectral Imaging System.

This article describes the adaptation of an existing aerial hyperspectral imaging system in a low-cost setup for collecting hyperspectral data in laboratory and field environment and spatial distortion assessments. The imaging spectrometer system consists of an ImSpector V9 hyperspectral pushbroom scanner, PixelFly high performance digital CCD camera, and a subsystem for navigation, position determination and orientation of the system in space, a sensor bracket and control system. The main objective of the paper is to present the system, with all its limitations, and a spatial calibration method. The results of spatial calibration and calculation of modulation transfer function (MTF) are reported along with examples of images collected and potential uses in agronomy. The distortion value rises drastically at the edges of the image in the near-infrared segment, while the results of MTF calculation showed that the image sharpness was equal for the bands from the visible part of the spectrum, and approached Nyquist’s theory of digitalization. In the near-infrared part of the spectrum, the MTF values showed a less sharp decrease in comparison with the visible part. Preliminary image acquisition indicates that this hyperspectral system has potential in agronomic applications.

Imaging performance of a CaWO4/CMOS sensor

The aim of this study was to investigate the modulation transfer function (MTF) and the effective gain transfer function (eGTF) of a non-destruc­­tive testing (NDT)/industrial inspection complementary metal oxide semi­conductor (CMOS) sensor in conjunction with a thin calcium tungstate (CaWO4) screen. Thin screen samples, with dimensions of 2.7x3.6 cm2 and thick­ness of 118.9 μm, estimated from scanning electron microscopy-SEM im­ages, were extracted from an Agfa Curix universal screen and coupled to the active area of an active pixel (APS) CMOS sensor. MTF was assessed using the slanted-edge method, following the IEC 62220-1-1:2015 method. MTF values were found high across the examined spatial frequency range. eGTF was found maximum when CaWO4 was combined with charge-coupled devices (CCD) of broadband anti-reflection (AR) coating (17.52 at 0 cycles/mm). The com­bi­nation of the thin CaWO4 screen with the CMOS sensor provided very pro­mis­ing image resolution and adequate efficiency properties, thus could be also con­sidered for use in CMOS based X-ray imaging devices, for various applications.

Design of a dual DMDs camera for high dynamic range imaging

A dual digital micromirror devices (DMDs) camera for high dynamic range imaging is presented. The dual DMDs camera consists of two DMDs, an objective imaging lens, and a reimaging lens, both of which were connected by a symmetric relay imaging lens whose responsibility is to correct the off-axis aberrations caused by the two tilted DMDs. The dual DMDs camera can meet a dynamic range of 216 dB in maximum when the gray level of imaging sensor (CMOS) is 12 bits, comparing with the single DMD camera whose dynamic range, on the same terms, is only 144 dB in maximum. In our final design, the aberration is well corrected and the modulation transfer function values across the entire field of the whole system are above 0.3 at 37 line pairs/mm.

Influence of angle kappa and angle alpha on visual quality after implantation of multifocal intraocular lenses

To assess the influence of angle kappa (κ) and angle alpha (α) on visual quality after multifocal intraocular lens (IOL) implantation. Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China. Prospective case series. Patients with cataract had phacoemulsification with TECNIS Symfony IOL implantation. The preoperative angle κ and angle α were measured using the iTrace device. Distance, intermediate, and near visual acuities were recorded 3months postoperatively. The Optical Quality Analyzing System was used to measure the objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, and Strehl ratio. A patient questionnaire was also administered. The study comprised 29 patients (57 eyes). Monocularly, the mean postoperative logarithm of the minimum angle of resolution (logMAR) uncorrected distance, intermediate, and near visual acuities were 0.03±0.09 (SD), 0.05±0.11, and 0.11±0.09, respectively. The mean postoperative logMAR corrected distance, distance-corrected intermediate, and distance-corrected near visual acuities were -0.01±0.05, 0.04±0.09, and 0.11±0.08, respectively. The mean OSI, MTF cutoff, and Strehl ratio were 1.27±0.84, 32.03±10.80 cycles per degree, and 0.17±0.05, respectively. The OSI (r=0.398, P=.005), MTF (r=-0.437, P=.002), and Strehl ratio (r=-0.419, P=.003) values were significantly correlated with angle κ. There was no correlation with angle α. Angle κ affected the objective visual quality multifocal after IOL implantation. The decision to implant a multifocal IOL should be carefully considered for patients with a large angle κ.

Design and fabrication of a wide-angle off-axis three-mirror head-mounted display system

A lightweight, compact and wide field of view (FOV) reflective type head-mounted display (HMD) system with off-axis three-mirror (OTM) imaging technology is proposed. The surfaces of all the mirrors in this system are freeform type, which possess excellent aberration correction properties even with fewer optical elements for a compact design. The design and optimization process of the proposed wide FOV OTM-HMD system are described in detail. Our HMD system has a diagonal FOV of 40 degrees and the maximum distortion of the system is less than 5%. The modulation transfer function (MTF) value was found to be larger than 0.1 at the spatial frequency of 60 cycles/mm. A binocular prototype (total size: 160 mm × 56 mm × 36 mm) meeting the human ergonomic requirements was built using the proposed design and the optical performance of the prototype was tested. While being compact, lightweight and cost-efficient, the optical performance of our OTM-HMD system is comparable to that of other previously reported HMD systems.

Validation of the tail replacement method in MTF calculations using the homogeneous and non-homogeneous edges of a phantom

We validated the tail replacement technique in the modulation transfer function (MTF) calculation of CT images using edges of homogeneous and non-homogeneous phantom using an automated method. The algorithm for the automated MTF calculation consists of several steps. The upper edge of the phantom was detected from its axial image and pixel values was taken to create an edge spread function (ESF). The left tail of the ESF was flipped horizontally to replace the right tail. Differentiating the ESF produced a line spread function (LSF) which was Fourier transformed to produce the MTF. To validate the result for the non-homogeneous phantom was compared with that for a homogeneous phantom. Results showed that in the homogeneous module, the MTF curve generated without tail replacement corresponded to its shape in use. However for the non-homogeneous module, the MTF obtained without tail replacement differed considerably from its shape in use. The 50% value of MTF (MTF-50) without tail replacement was 0.44 cycles/mm compared to 0.33 cycles/mm in use. Using the tail replacement, the MTFs in the homogeneous and non-homogeneous modules were comparable, with MTF-50 values of 0.33 cycles/mm for both. In summary, the MTF cannot be conventionally measured from the edge of the non-homogeneous module, but it can be resolved using the tail replacement technique on the ESF curve.

Visual quality and performance following bilateral implantation of TECNIS Symfony intraocular lenses with or without micro-monovision.

Purpose: To evaluate the visual quality and performance of TECNIS Symfony intraocular lenses (IOLs) implanted with or without micro-monovision approach.Setting: Chongqing Aier Mega Eye Hospital, Chongqing, China; Daping Hospital of Army Medical University, Chongqing, China.Design: Prospective study.Methods: The study comprised 70 cataract patients who had bilateral implantation of TECNIS Symfony extended range of vision IOLs, either with intended micro-monovision (monovision group: 35 patients) or with intended emmetropia (control group: 35 patients). Visual acuity, modulation transfer function (MTF), defocus curve, spectacle independence, and photic phenomena were analyzed 3 months postoperatively.Results: There was no significant difference between the two groups in binocular uncorrected visual acuity at distance. Mean binocular uncorrected visual acuity at intermediate (monovision: 0.81 dec; control: 0.58 dec) and near (monovision: 0.59 dec; control: 0.30 dec) were significantly better in the monovision group. In the monovision group, the difference of MTF values between the dominant and the non-dominant eyes was not statistically significant and MTF values were within the normal range for both eyes. Spectacle independence at intermediate and near was statistically significantly higher in the monovision group compared to the control group. The incidence of photic phenomena was similar in both groups.Conclusion: Micro-monovision implantation of TECNIS Symfony IOLs provided a superior range of visual acuity from far to near and higher spectacle independence compared to a control group targeted for emmetropia.

Optical design and laboratory test of an internal pushbroom hyperspectral microscopy

Hyperspectral imaging is an emerging technology for various medical applications, especially in disease diagnosis of early and biomedical research based on their unique spectral signatures. A hyperspectral microscopy based on a prism-grating-prism is designed for various medical applications. The spectral range between 400 nm to 800 nm is sampled by 256 spectral channels, the modulation transfer function (MTF) values of full spectrum and full field of view are close to the diffraction limit, the smile is less than 6.4% of a pixel, and the keystone is less than 1.6% of a pixel. At the same time, the hyperspectral microscopy used an internal pushbroom technology, which has the advantages of compact structure and good portability. The spectral imaging results demonstrate the great potential of this internal pushbroom hyperspectral microscopy for the pathologists to automatically detect tumor tissue in pathological slides and early disease diagnosis.

Design of dual-band infrared zoom lens with multilayer diffractive optical elements.

A mid-wave infrared (MWIR)/long-wave infrared (LWIR) dual-band zoom lens design with multilayer diffractive optical elements (MLDOEs) is presented. The mathematical relationship between the substrate material selection for dual-band MLDOE and polychromatic integral diffraction efficiency (PIDE) is deduced in the oblique incident situation, and further, a method for optimal selection of substrate material is proposed to obtain the high PIDE in an incident angle range. In the optimization process, the optimal substrate material combination is selected based on the proposed method, and the principle of lens material replacement is discussed. After optimization, the 5× hybrid dual-band infrared zoom system is obtained, which consists of seven lenses. The modulation transfer function values in all configurations are larger than 0.5 and 0.3 in MWIR and LWIR, respectively. The distortion values are less than 2% both in MWIR and LWIR for all configurations.