Modulation Transfer Function Analysis Research Articles

Quality Analysis of Unmanned Aerial Vehicle Images Using a Resolution Target

Unmanned aerial vehicle (UAV) photogrammetry is an emerging means of acquiring high-precision rapid spatial information and data because it is cost-effective and highly efficient. However, securing uniform quality in the results of UAV photogrammetry is difficult due to the use of low-cost navigation devices, non-surveying cameras, and rapid changes in shooting locations depending on the aircraft’s behavior. In addition, no specific procedures or guidelines exist for performing quantitative quality tests or certification methods on UAV images. Additionally, test tools for UAV image quality assessment only use the ground sample distance (GSD), often resulting in a reduced image quality compared with that of manned aircraft images. In this study, we performed a modulation transfer function (MTF) analysis using a slanted edge target and a GSD analysis to confirm the necessity of MTF analysis in UAV image quality assessments. In this study, we aimed to address this issue by conducting a modulation transfer function (MTF) analysis using a slanted edge target and a ground sample distance (GSD) analysis. This was carried out to confirm the necessity of MTF analysis in evaluating UAV image quality. Furthermore, we analyzed the impact of flight height and mounted sensors on image quality at different study sites.

Performance evaluation of six digital mammography systems

The strong advance in digital mammography as a tool for breast cancer screening requires that the new systems be characterized. Quality control protocols describe the methodology to evaluate systems performance. Detective quantum efficiency (DQE) is the most suitable parameter for describing the imaging performance of an X-ray imaging device. The objective of this study was to characterize in terms of DQE six digital mammography systems, at different detector air kerma (DAK) levels for a variety of beam qualities. A Carestream EHR-M3 CR detector, a small field digital mammography system Siemens Opdima, and full field digital mammography systems Planmed Clarity, GE Essential, GE Pristina and GE Crystal Nova were characterized using the European Guidelines protocol. Modulation transfer function (MTF), normalized noise power spectrum (NNPS) and DQE were determined, for an extended detector air kerma range. Attenuated beam qualities (obtained by adding 2 mm Al to the corresponding beam qualities) used were 28 kV with anode/filter combination Mo/Mo for the EHR-M3, Opdima, Essential and Pristina systems; 28 kV W/Ag for the Clarity; 28 kV W/Rh for the Crystal Nova; 28 kV Mo/Rh for the EHR-M3; and 34 kV Rh/Ag for the Pristina. Two groups were identified in MTF analysis, and the group composed of Clarity, Opdima and Essential presented the highest MTF values. In NNPS analysis, three main groups were identified, in which the systems Crystal Nova and Essential presented lower and higher NNPS, respectively. Crystal Nova system also exhibited higher DQE values for low spatial frequencies, while Opdima and Clarity presented higher DQE values for medium to high spatial frequency. Agreement with data from literature indicates that the systems evaluated are operating under typical conditions. Evidence of improvement in detectors performance was found.

Fourier analysis of multi-scale neural networks implemented for high-resolution X-ray radiography

To realize high-resolution X-ray imaging, this study trains deep neural networks comprising multi-scale encoder/decoder architectures with actual data measured using a low-resolution imaging detector. The network performance is evaluated in the Fourier domain through measurements of the modulation-transfer function (MTF) and noise-power spectrum (NPS), which decompose the contrast and noise power (or variance) in terms of the spatial-frequency components. The designed networks are found to successfully deblur blurry images. The MTF analysis reflects the conventional mean-squared errors and structural similarities within it. Moreover, it indicates the over-regression property of the networks that could not be addressed via the conventional metrics. The NPS analysis reveals that the networks suppressed high-frequency noise. The Fourier analysis shows that the designed networks attempted to match the fidelity between the input and label, while suppressing noise.

Modulation transfer function variation through anisotropic turbulence in biological tissue

Analysis of the long-exposure modulation transfer function (MTF) is performed for optical imaging using plane and spherical waves through anisotropic turbulence in biological tissues. To obtain the MTF, the wave structure functions of plane and spherical waves are obtained in closed-form expressions. Results are presented depending on various parameters of the turbulent medium and optical beam. The positive effect of anisotropy on optical imaging is remarkable in turbulent biological tissues. Besides scattering and absorption, taking anisotropy into account as well as turbulence will lead to a more accurate description of the performance of the medical imaging systems that use optical spectrums in biological tissues.

Characterization of Effects of Compressed Sensing on High Spectral and Spatial Resolution (HiSS) MRI with Comparison to SENSE.

High Spectral and Spatial resolution (HiSS) MRI shows high diagnostic performance in the breast. Acceleration methods based on k-space undersampling could allow stronger T2*-based image contrast and/or higher spectral resolution, potentially increasing diagnostic performance. An agar/oil phantom was prepared with water-fat boundaries perpendicular to the readout and phase encoding directions in a breast coil. HiSS MRI was acquired at 3T, at sensitivity encoding (SENSE) acceleration factors R of up to 10, and the R = 1 dataset was used to simulate corresponding compressed sensing (CS) accelerations. Image quality was evaluated by quantifying noise and artifact levels. Effective spatial resolution was determined via modulation transfer function analysis. Dispersion vs. absorption (DISPA) analysis and full width at half maximum (FWHM) quantified spectral lineshape changes. Noise levels remained constant with R for CS but amplified with SENSE. SENSE preserved the spatial resolution of HiSS MRI, while CS reduced it in the phase encoding direction. SENSE showed no effect on FWHM or DISPA markers, while CS increased FWHM. Thus, CS might perform better in noise-limited or geometrically constrained applications, but in geometric configurations specific to breast MRI, spectral analysis might be compromised, decreasing the diagnostic performance of HiSS MRI.

Postoperative discoloration of a multifocal hydrophobic acrylic lens: case report with laboratory analyses

Introduction: A case of discoloration of a multifocal hydrophobic acrylic intraocular lens (IOL), which was explanted and exchanged as well as underwent laboratory analysis, is reported. Patient and Clinical Findings: The patient presented with a corrected distance visual acuity of 20/50 and glare in the right eye 8 years after implantation. Slitlamp examination revealed a nasally decentered IOL with a whitish-brownish haze throughout. Diagnosis, Intervention, and Outcomes: The discolored IOL (ZMB00) was explanted and exchanged for a 3-piece IOL (sulcus fixation). Grossly, the explanted IOL showed a whitish discoloration of the optic only after hydration, corresponding to a yellowish-brownish discoloration observed under light microscopy. Back light scattering revealed bulk scatter throughout the optic. Light transmittance (%T) showed a slight progressive decrease starting at 500 nm when compared with %T in the directions for use (DFUs). Although modulation transfer function analysis demonstrated similar values to the control lens, the contrast of U.S. Air Force targets appeared slightly decreased. Conclusions: To the authors' knowledge, this is the first reported case of a discolored ZMB00 IOL that underwent explantation and laboratory assessment. Although current analyses did not reveal the etiology of the discoloration, surgeons should be aware of this possible occurrence with this lens design and carefully assess signs and symptoms before explantation.

MDCT에서 ACR 팬텀의 구성 물질에 따른 공간분해능 연구

The modulation transfer function (MTF) is well known as a crucial parameter in quality assurance of computed tomography (CT) scanners that provides detailed information of both contrast and resolution of CT images. In this study, modulation transfer function (MTF) of multi-detector computed tomography (MDCT) was evaluated by changing the substance of phantom and the measurement parameters. The analysis of MTF gives following results: 1) Bone (the highest contrast material) and air (the lowest contrast material) exhibited variance by 0.030 lp/cm at MTF(50%). 2) In addition, slice thickness of 1.25-mm and 10.0-mm exhibited 0.110 lp/cm and 0.065 lp/cm at MTF(50%), respectively. 3) MTF (50%) showed 50.31% difference depending on the image reconstruction algorithm. Especially, bone algorithm showed higher MTF (50%) than standard algorithm by 26.69%. 4) In addition, the Full (360°) mode linear interpolation showed higher MTF (50%) than the Plus (540°) mode by 10.71%. For a accurate measurement of MTF while performing CT quality control, a phantom module which consists of diverse substance is required. Also, the optimal image which reflecting the size and shape of lesion can be obtained with a suitable scanning factor for diagnosis.

Enhancing the design by optimizing MTF performance of MLA with overlapping aperture

In this paper, we introduced a novel microlens array (MLA) design approach with the use of overlapped apertures. The chief ray tracing and paraxial imaging optics are utilised in projection imaging analysis. This work makes MLA structure design requirements more flexible. The proposed design is small and compact. It provides homogeneous illumination over the whole field of view (FOV). In the demonstration, a comparison of the sample 3x3 MLA projector and the proposed 3x3 MLA projector with the same aperture size is illustrated with the help of overlapped apertures. Finally, the proposed MLA projection imaging simulations are accomplished. It substantially outperforms the basic design in terms of FOV and modulation transfer function (MTF). We performed comparative analysis for proposed design with the help of diffraction MTF analysis tool. Our research will aid in the development and exploration of more efficient and advanced compact MLA projection optical systems.

Visual and refractive outcomes of new intraocular lens implantation after cataract surgery

To report the visual and refractive outcomes of new aspheric hydrophobic acrylic monofocal intraocular lens (IOL). Retrospective case series. This study included eyes of patients who underwent routine cataract surgery for uncomplicated age-related cataract with implantation of a Aktis SP (NS-60YG; Nidek Co. Ltd., Japan) IOL and attended regular follow ups at 1 week, 1 month, 3 months, and 12 months. At each post-operative visit, ophthalmological evaluation included measurement Uncorrected (UCVA) and Best corrected visual acuity (BCVA), contrast sensitivity, posterior capsular opacification (PCO), optical aberrations, analysis of point spread function (PSF) and modulation transfer function (MTF). The study included 2102 eyes of 1358 patients aged 45 to 75 years (mean age 62.6 years ± 5.6 SD). The mean preoperative BCVA was 0.56 ± 0.26 logMAR. At 1 year follow up, the mean postoperative UCVA and BCVA were 0.11 ± 0.09 and 0.02 ± 0.03 logMAR, respectively. At the end of 6 months, around 1487 (93%) eyes had BCVA of 20/20 and better than 20/30 in 100% of the eyes. Mild posterior capsule opacification (PCO) was observed in 56 patients, but none required Nd YAG laser capsulotomy. There was reduction in ocular spherical aberration and Higher order aberrations (HOAs) as compared to pre operative. This explains better contrast sensitivity obtained by MTF and PSF values. The study shows that the Aktis SP IOL is safe, effective, and stable lens that could be inserted through 2.2 mm incision with satisfactory visual and refractive outcomes, even in late post-operative period.

Analysis of MTF for Optical Waves Propagation in Hypersonic Plasma Turbulence

In this study, new expressions for wave structure functions (WSFs) for optical planes and spherical waves propagating in plasma turbulence are derived based on the refractive index undulation power spectrum of hypersonic plasma turbulence and Rytov approximation theory. On this basis, the mathematical expressions for plasma turbulence modulation transfer function (MTF) for optical planes and spherical waves are obtained using WSF expression. The mathematical expressions describe the attenuation effect of plasma turbulence on optical imaging systems. The effects of different wavelengths, turbulent outer scales, and refractive index undulation variance on plasma turbulence MTF were calculated and analyzed. Results show that increasing the incident wavelength reduces the effect of plasma turbulence on the imaging system. Moreover, increasing the turbulence outer scale and reducing the refractive index undulation variance can also improve the imaging results.

On-orbit thermal deformation prediction for a high-resolution satellite camera

Thermal-structural analysis of satellite camera in the early design phase as well as during the later experimental verification is important due to the extreme thermal environment. The purpose of this work is to numerically investigate the thermal deformation for a high-resolution satellite camera under solar radiation. Based on the on-orbit thermal environment of the geosynchronous orbit, thermal-structural finite element model of the satellite camera is developed and opto-thermo-mechanical analysis of the optical system is proposed. Transient temperature distributions of the satellite camera under different extreme heat loads are obtained. Mirror deformations, translation and rotation have been introduced to the optical analysis and modulation transfer function analysis has been performed. Numerical simulation results reveal the dynamic response of the optical system under transient temperature and the thermal vacuum test predicts the imagery quality of the satellite camera, which can provide guidance for designers to analyze the on-orbit stability for the optical camera.

Modulation Transfer Function Analysis in Myopic Model Eye

Hitherto, the eye modelling is based on the emmetropic eye taken its ocular optical components value from the population-based studies. However, no studies have been done to study the effect of aberration of myopic refractive error by modelling the eye using the parameters from ocular biometrics and ray tracing method. This study aimed to determine the modulation transfer function (MTF) of myopic refractive error using eye modelling and ray tracing technique. Three eye models had been successfully modelled in Zemax software, namely, emmetropic Liou and Brennan, myopic Liou and Brennan, corrected myopic Liou and Brennan. The optical performance of the eye models were tested using the MTF. From the MTF analysis at 100 cycles/mm, the MTF value of both tangential and sagittal rays for myopic Liou and Brennan eye was the lowest compared to its emmetropic model. Also, the MTF value of the corrected myopic Liou and Brennan model was higher compared to the uncorrected myopic model. However, the corrected myopic model produced lower MTF values for both tangential and sagittal MTF compared with the emmetropic model of Liou and Brennan. In this study, the accuracy of the MTF for myopia correction and emmetropia were calculated. It was found that the accuracy of the MTF value for corrected myopia at tangential and sagittal rays was lower.

Theory, method, and test tools for determination of 3D MTF characteristics in cone-beam CT.

The modulation transfer function (MTF) is widely used as an objective metric of spatial resolution of medical imaging systems. Despite advances in capability for three-dimensional (3D) isotropic spatial resolution in computed tomography (CT) and cone-beam CT (CBCT), MTF evaluation for such systems is typically reported only in the axial plane, and practical methodology for assessment of fully 3D spatial resolution characteristics is lacking. This work reviews fundamental theoretical relationships of two-dimensional (2D) and 3D spread functions and reports practical methods and test tools for analysis of 3D MTF in CBCT. Fundamental aspects of 2D and 3D MTF measurement are reviewed within a common notational framework, and three MTF test tools with analysis code are reported and made available online (https://istar.jhu.edu/downloads/): (a) a multi-wire tool for measurement of the axial plane MTF [denoted as , where is the measurement angle out of the axial plane] as a function of position in the axial plane; (b) a wedge tool for measurement of the MTF in any direction in the 3D Fourier domain [e.g., =45°, denoted as ]; and (c) a sphere tool for measurement of the MTF in any or all directions in the 3D Fourier domain. Experiments were performed on a mobile C-arm with CBCT capability, showing that yields an informative one-dimensional (1D) representation of the overall 3D spatial resolution characteristics, capturing important characteristics of the 3D MTF that might be missed in conventional analysis. The effects of anisotropic filters and detector readout mode were investigated, and the extent to which a system can be said to provide "isotropic" resolution was evaluated by quantitative comparison of MTF at various . All three test tools provided consistent measurement of , and the wedge and sphere tools demonstrated how measurement of the MTF in directions outside the axial plane ( ) can reveal spatial resolution characteristics to which conventional axial MTF measurement is blind. The wedge tool was shown to reduce statistical measurement error compared to the sphere tool due to improved sampling, and the sphere tool was shown to provide a basis for measurement of the MTF in any or all directions (outside the null cone) from a single scan. The C-arm system exhibited non-isotropic spatial resolution with conventional non-isotropic 1D apodization filters (i.e., frequency cutoff filters) - which is common in CBCT - and implementation of isotropic 2D apodization yielded quantifiably isotropic MTF. Asymmetric pixel binning modes were similarly shown to impart non-isotropic effects on the 3D MTF, and the overall 3D MTF characteristics were evident in each case with a single, 1D measurement of the 1D ). Three test tools and corresponding MTF analysis methods were presented within a consistent framework for analysis of 3D spatial resolution characteristics in a manner amenable to routine, practical measurements. Experiments on a CBCT C-arm validated many intuitive aspects of 3D spatial resolution and quantified the extent to which a CBCT system may be considered to have isotropic resolution. Measurement of ) provided a practical 1D measure of the underlying 3D MTF characteristics and is extensible to other CT or CBCT systems offering high, isotropic spatial resolution.

Fast full-field modulation transfer function analysis for photographic lens quality assessment.

Full-field modulation transfer function (MTF) data based on the slanted-edge method can give useful insights on the performance of a photographic lens sample and its shortcomings. Decentering and other out-of-tolerance states are recognized easily. A process to derive accurate lens MTF from slanted-edge spatial frequency response measurements is presented, covering chart design and alignment, data capture by standard digital cameras, slanted-edge algorithm implementation requirements, sensor and chart MTF corrections, and also visualization of the results. It is demonstrated that the reliability of the measured MTF values is by far good enough to support automated quality assessment with a measurement accuracy of ≈0.02 MTF and repeatability of ≲0.005 up to 100 c/mm. The measured full-field MTF values provide an unambiguous numerical criterion for comparison with expectations based on lens design.

High resolution >40 keV x-ray radiography using an edge-on micro-flag backlighter at NIF-ARC.

Radiography of low-contrast features in high-density materials evolving on a nanosecond timescale requires a bright photon source in the tens of keV range with high temporal and spatial resolution. One application for sources in this category is the study of dynamic material strength in samples compressed to Mbar pressures at the National Ignition Facility, high-resolution measurements of plastic deformation under conditions relevant to meteor impacts, geophysics, armor development, and inertial confinement fusion. We present radiographic data and the modulation transfer function (MTF) analysis of a multi-component test object probed at ∼100 keV effective backlighter energy using a 5 μm-thin dysprosium foil driven by the NIF Advanced Radiographic Capability (ARC) short-pulse laser (∼2 kJ, 10ps). The thin edge of the foil acts as a bright line-projection source of hard x rays, which images the test object at 13.2× magnification into a filtered and shielded image plate detector stack. The system demonstrates a superior contrast of shallow (5 μm amplitude) sinusoidal ripples on gold samples up to 90 μm thick as well as enhanced spatial and temporal resolution using only a small fraction of the laser energy compared to an existing long-pulse-driven backlighter used routinely at the NIF for dynamic strength experiments.

Innovative monochromatic x-ray source for high-quality and low-dose medical imaging.

An estimated 377 million diagnostic and interventional radiological exams are performed annually in the United States and approximately 4 to 5 billion globally. All use x-ray tubes that emit x-rays over a broad energy band, a technology that is more than a century old. Only a small fraction of the radiation is useful for imaging while the remaining fraction either increases the radiation dose received by the patient or degrades the image. Monochromatic x-rays can provide lower dose images in many of these radiological applications while maintaining or improving image quality. We report the development of the first monochromatic x-ray source suitable for low-dose, high-quality imaging in the clinic and demonstrate its first application and performance with mammography phantoms. X-ray fluorescence was used to generate monochromatic x-rays with selectable energies from 18 to 60keV. This patented technology was incorporated into a laboratory prototype of a monochromatic x-ray mammography system. Image quality was evaluated as a function of radiation dose in standard breast phantoms using the signal-to-noise ratio (SNR) measured for high and low contrast masses and microcalcifications. Spatial imaging properties were assessed from these images as well as from modulation transfer function (MTF) analysis. Measurements using an iodine contrast agent were also performed. The results were compared to those obtained using a commercially available, conventional x-ray mammography system. Our prototype system reduced radiation dose by factors of five to ten times for the same SNRs as obtained from the conventional system. This performance was demonstrated in phantoms simulating a wide range of lesion sizes and microcalcifications in a variety of breast thicknesses. The high SNRs for very thick breast phantoms provide evidence that screening with less breast compression is possible while maintaining image quality. Contrast-enhanced digital mammography (CEDM) with monochromatic x-rays was shown to provide a simpler and more effective technique at substantially lower radiation dose. The MTF value at 20% was 9lp/mm. The monochromatic x-ray system is more sensitive for imaging a wide range of breast sizes and compositions than conventional broadband mammography. High image quality and lower dose are its hallmarks. It also makes CEDM much more effective than current methods developed for use with conventional broadband mammography systems.

Influence of Reading on Smartphone Screens on Visual Optical Quality Metrics and Tear Film Stability.

To evaluate the impact of a prolonged reading session on a smartphone screen on optical quality metrics and tear film stability. This prospective study was conducted in 41 healthy volunteers who were asked to read an article on a smartphone screen for 20 minutes. The following tests were performed before the reading task in this consecutive order and repeated after the reading task in the same order: automated noninvasive tear break-up time, optical quality assessment including Objective Scatter Index (OSI), modulation transfer function, Strehl ratio, and tear film dynamic analysis as follows: vision break-up time (VBUT) as a function of OSI changes within 20 seconds, using a double-pass aberrometer imaging system, and fluorescein tear break-up time (FBUT) measured using the slit lamp. All break-up time-related parameters (noninvasive tear break-up time, FBUT and VBUT) were significantly reduced after the reading task (P < 0.01). The OSI was significantly worsened after the reading task (P = 0.01), whereas all the other optical quality metrics (modulation transfer function and Strehl ratio) slightly deteriorated, were not statistically significant. A significant correlation was found between the shortening of the FBUT, VBUT, and the worsening of the OSI (r = -0.33, P < 0.05). A reading session on a smartphone screen in healthy subjects was found to significantly affect the tear film stability and objectively worsen the retinal image quality.

Multiplane differential phase contrast imaging using asymmetric illumination in volume holographic microscopy.

.Significance: Differential phase contrast (DPC) is a well-known imaging technique for phase imaging. However, simultaneously acquiring multidepth DPC images is a non-trivial task. We propose simultaneous multiplane DPC imaging using volume holographic microscopy (VHM).Aim: To design and implement a new configuration of DPC-VHM for multiplane imaging.Approach: The angularly multiplexed volume holographic gratings (AMVHGs) and the wavelength-coded volume holographic gratings (WC-VHGs) are used for this purpose. To obtain asymmetric illumination for DPC images, a dynamic illumination system is designed by modifying the regular Köhler illumination using a thin film transistor panel (TFT-panel).Results: Multidepth DPC images of standard resolution chart and biosamples were used to compare imaging performance with the corresponding bright-field images. An average contrast enhancement of around three times is observed for target resolution chart by DPC-VHM. Imaging performance of our system is studied by modulation transfer function analysis, which suggests that DPC-VHM not only suppresses the DC component but also enhances high-frequency information.Conclusions: Proposed DPC-VHM can acquire multidepth-resolved DPC images without axial scanning. The illumination part of the system is adjustable so that the system can be adapted to bright-field mode, phase contrast mode, and DPC mode by controlling the pattern on the TFT-panel.

Noise reduction in CT image using prior knowledge aware iterative denoising

The clinical demand for low image noise often limits the slice thickness used in many CT applications. However, a thick-slice image is more susceptible to longitudinal partial volume effects, which can blur key anatomic structures and pathologies of interest. In this work, we develop a prior knowledge aware iterative denoising (PKAID) framework that utilizes spatial data redundancy in the slice increment direction to generate low-noise, thin-slice images, and demonstrate its application in non-contrast head CT exams. The proposed technique takes advantage of the low noise of thicker images and exploits the structural similarity between the thick- and thin-slice images to reduce noise in the thin-slice image. Phantom data and patient cases (n = 3) of head CT were used to assess performance of this method. Images were reconstructed at clinically utilized slice thickness (5 mm) and thinner slice thickness (2 mm). PKAID was used to reduce image noise in 2 mm images using the 5 mm images as low-noise prior. Noise amplitude, noise power spectra (NPS), modulation transfer function (MTF), and slice sensitivity profiles (SSPs) of images before/after denoising were analyzed. The NPS and MTF analysis showed that PKAID preserved noise texture and resolution of the original thin-slice image, while reducing noise to the level of thick-slice image. The SSP analysis showed that the slice thickness of the original thin-slice image was retained. Patient examples demonstrated that PKAID-processed, thin-slice images better delineated brain structures and key pathologies such as subdural hematoma compared to the clinical 5 mm images, while additionally reducing image noise. To test an alternative PKAID utilization for dose reduction, a head exam with 40% dose reduction was simulated using projection-domain noise insertion. The image of 5 mm slice thickness was then denoised using PKAID. The results showed that the PKAID-processed reduced-dose images maintained similar noise and image quality compared to the full-dose images.

Multizonal Design Multifocal Intraocular Lens-Induced Astigmatism According to Orientation.

To evaluate the differences in intraocular lens (IOL)-induced astigmatism according to differences in orientation of a multizonal multifocal IOL, the Precizon Presbyopic NVA IOL (Ophtec BV). The clinical study reviewed 80 eyes from 40 patients with cataracts who underwent Precizon Presbyopic IOL implantation. Residual astigmatism, as measured by autorefraction and manifest refraction, was investigated using vector analysis of eyes implanted with vertical (90 ± 30 degrees) and horizontal (180 ± 30 degrees) orientations of the first near segment of the IOL. In the ray-tracing simulation study, pseudophakic eyes with the Precizon Presbyopic IOL were modeled. The modulation transfer function (MTF) of each case was compared with respect to the amount of corneal astigmatism of the model eyes and the orientation of the first near segment. The mean IOL-induced astigmatism measured by autorefraction was 0.68 ± 0.58 diopters (D) at 1 degree in the vertical orientation of the first near segment (n = 52) and 1.05 ± 0.81 D at 96 degrees in the horizontal orientation (n = 28). However, the mean IOL-induced astigmatism measured by manifest refraction was 0.14 ± 0.44 D at 171 degrees and 0.46 ± 0.40 D at 95 degrees. The MTF analysis showed that the highest MTF values were measured in eyes without corneal astigmatism in both the vertically and horizontally implanted IOLs. Autorefraction measurement indicates induction of with-the-rule astigmatism by the Precizon Presbyopic IOL when implanted vertically with respect to the first near segment, and against-the-rule astigmatism when implanted horizontally. However, this astigmatism is clinically insignificant according to manifest refraction and ray-tracing simulation. [J Refract Surg. 2020;36(11):740-748.].