NIH Public Access Author Manuscript J Refract Surg. Author manuscript; available in PMC 2007 January 8.

Size: px
Start display at page:

Download "NIH Public Access Author Manuscript J Refract Surg. Author manuscript; available in PMC 2007 January 8."

Transcription

1 NIH Public Access Author Manuscript Published in final edited form as: J Refract Surg ; 21(5): S547 S551. Influence of Exposure Time and Pupil Size on a Shack-Hartmann Metric of Forward Scatter William J. Donnelly III, MS and Raymond A. Applegate, OD, PhD From Visual Optics Institute, College of Optometry, University of Houston, Houston, Tex. Abstract PURPOSE: To determine the influence of exposure time and pupil size on a Shack-Hartmann (S/ H) derived metric of forward scatter (MAX_SD) using a physical model of nuclear cataract. METHODS: A physical model eye was developed and mounted to a S/H wavefront sensor. The eye model consisted of a lens, variable pupil, simulated cataract, and retina. Located behind the pupil, a cuvette contained one of five polystyrene microsphere solutions simulating five levels of nuclear cataract severity. Cataract severity was described using a S/H derived metric of forward scatter (MAX_SD), which measures aspects of forward scatter contained in the S/H lenslet point spread functions (PSF). To determine the impact of exposure time and pupil size, measurements of MAX_SD were regressed against cataract severity for three different exposure times and three different pupil sizes. RESULTS: MAX_SD was well correlated to cataract severity. Exposure time had the largest influence, and pupil size had the smallest influence on the forward scatter metric. When pupil size and exposure time were allowed to vary and image saturation was allowed to occur, MAX_SD explained 83% of the variance in cataract severity. Excluding images where saturation occurred, holding optimal exposure time constant, and varying pupil size, MAX_SD explained 97% of the variance in cataract severity. CONCLUSIONS: The ability of the forward scatter metric derived from S/H measurements to predict cataract severity for a longitudinal study is optimized by selecting a patient-specific exposure at the initial cataract assessment to avoid saturation and maximize the dynamic range of the system. This patient-specific exposure should be used in all future visits. At the University of Houston College of Optometry Visual Optics Institute, we are developing methods to use Shack-Hartmann (S/H) images to characterize both wavefront error and forward light scatter from the eye in one single measurement. 1 To validate and improve our techniques, we developed a physical model of nuclear cataract with controllable parameters. We simulated nuclear cataract to create forward light scatter and test the effects of pupil size and exposure time on our ability to predict nuclear cataract severity. FORWARD SCATTER VS BACKSCATTER Intraocular light scatter is light that has reflected, refracted, diffracted, or experienced multiple combinations of all three from particles along the optical path of travel. 2 If the scattered light reaches the retina it is called forward scatter. If the scattered light ends up leaving the eye before Correspondence: William J. Donnelly III, MS, Visual Optics Institute, College of Optometry, University of Houston, Houston, TX Tel: ; Fax: ; wdonnelly@uh.edu. Dr Applegate has proprietary interests in metrics of forward scatter. This work was supported in part by NIH grant R01 EY05820 to Dr Applegate and CORE grant P30 EY07551 to the College of Optometry, University of Houston, Houston, Tex.

2 Donnelly and Applegate Page 2 hitting the retina it is called backscatter. Forward scatter degrades image formation. 2 Backscatter does not degrade image formation. Backscatter decreases the available light in the retinal image. Forward light scatter causes contrast loss 3,4 and is reported perceptually as glare, halos, or coronae. 5,6 The cornea, iris, sclera, retina, and lens are all sources of light scatter. 7 Light scatter from these sources can be aggravated by ocular trauma, disease, or surgery. 6 The lens is normally the largest contributor to light scatter. 7,8 With advancing cataract, light scatter from the lens increases while other sources of scatter remain relatively stable. 7,9 As cataract severity increases, forward scatter in the lens dominates over backscatter. 9 Forward scatter has proven difficult to measure objectively. 5,10 Backscatter can be measured noninvasively in an attempt to predict forward scatter. 8,9 Methods to measure backscatter include slit-lamp imaging of cataract and grading (eg, LOCS-III) and Scheimpflug densitometry. 8,11,12 These tools (particularly the slitlamp) are commonly used to assess cataract severity. A major problem with using backscatter to predict forward scatter in cataract is that with Mie scattering, no direct relationship exists when particle size and density varies over a large range. 2,9 Researchers and clinicians are aware that backscatter measures are indirect measures of forward scatter and lacking when used to predict visual performance. 5,13,14 Thibos and Hong 15 suggested measuring forward scatter as a new application of S/H technology and Applegate and Thibos 16 were the first to report observations using a S/H wavefront sensor (SHWS) to measure forward scatter. Applegate and Thibos capitalized on the fact that in S/H wavefront sensing, light from a probe beam forms a point source on the retina. Light from this retinal point source travels in a forward direction towards the pupil. As the wavefront travels through the eye, light is scattered by the ocular media in a forward direction coming out of the eye through the pupil. It is reasoned, in patients with nuclear cataract, that forward scatter outbound over a full pupil originating from a retinal point source is reasonably equivalent (as scattering elements are fairly uniformly distributed in an anterior posterior direction) to forward scatter inbound to the retina from a distant object point source. However, it is acknowledged that it will not be exactly the same. Shack-Hartmann estimates of cortical and posterior sub-capsular cataract will have less reversibility than nuclear cataract due to their anterior and/or posterior localization. Nonetheless, it is fully anticipated that cortical and posterior sub-capsular cataract will have their unique S/H image signatures. Here we focus on nuclear cataract as a first step in a systematic development of the technique. A major goal of the laboratory is to develop a physical model that could be used to test and develop a computer model of forward scatter. A computer model that can replicate different physical eyes will facilitate development of better metrics in a time efficient manner. In developing this physical model, we took the opportunity to demonstrate the importance of proper exposure given the fact that current S/H systems purposely favor overexposure or use image processing to accentuate spot centers. MATERIALS AND METHODS PHYSICAL EYE MODEL To control all parameters during testing, we built a physical eye model (Fig 1). This system was developed in Zemax software (Zemax, San Diego, Calif) and was designed to match other researchers' modulation transfer function data on real eyes. 17,18 The main optic was a 19-mm focal length plano-convex silica lens with a diameter of 12.7 mm, n = Directly behind the lens was an adjustable pupil. To hold solutions of scattering media, an interchangeable glass cuvette followed directly behind the pupil plane. The cuvette, simulating a cataractous

3 Donnelly and Applegate Page 3 MEASUREMENTS ANALYSIS crystalline lens, was filled with various concentrations of 1-μm diameter microspheres in distilled water. 19 A cuvette path length of 5 mm was chosen to approximate a lens thickness equal to that of an older adult aged lens. 20 The retina of the system was a piece of white paper mounted to a locking micrometer drive allowing focus adjustment. Based on the work of Cox et al, 19 five levels of simulated nuclear cataract were chosen to span the range encountered in a clinical population of nuclear cataract patients. One cuvette contained only distilled water as a non-cataract configuration. Four cuvettes contained 1-μm microsphere solutions of increasing microsphere density to produce the same scatter profile function through a path of one half the length of the cuvette used by Cox et al. 19 This yielded microsphere solutions of 0.00%, 0.08%, 0.16%, 0.32%, and 0.48%. The physical eye model was mounted to the front of the SHWS, 21 and S/H images were acquired for the five cataract levels over 5-, 7-, and 9-mm pupils. Three exposure times were used: 100, 200, and 300 ms. The input source for the retinal guide star was held constant. Lenslet pitch was 400 μm and the lenslet focal length was 24 mm. 21 Cuvettes and pupil size could be changed without disturbing the positioning of the physical eye model. To reduce instrument noise, as in real eye measurements, background images were subtracted from the S/H images. Each lenslet point spread function (PSF) was individually analyzed and statistics were calculated on all lenslet data in the S/H image to extract a metric of forward scatter MAX_SD. To determine MAX_SD, the standard deviation is calculated from pixel values over a defined square area centered on a lenslet PSF peak. The sides of the square are equal to the average distance between adjacent lenslet peaks. MAX_SD is the maximum of all standard deviations from all lenslet PSFs in the image. If desired, greater detail of the calculation of MAX_SD can be found in Donnelly et al. 1 MAX_SD was regressed against cataract severity, represented as % microspheres in solution. To appropriately apply regression, the independent variable needs to be well distributed with respect to the dependent variable. To achieve such a distribution, the independent variable (cataract severity expressed as % microspheres in solution) was transformed by taking the square root of percent of microspheres in solution. OVEREXPOSED IMAGES RESULTS Overexposure caused pixel saturation in the S/H image, causing many pixels to have values near 255 (maximally white), artificially widening the lenslet PSFs (Fig 2C). To identify which S/H images were saturated (overexposed), we used an image histogram. An image histogram is a plot of the number of pixels having a particular value in a S/H image (after background subtraction) as a function of image value. Saturation can be observed in a S/H image histogram as a third peak near value 255, ie, an excessive number of pixels having many values near 255 (Fig 2A). Shack-Hartmann images without saturation (Fig 2D) do not exhibit a third peak (no excessive white pixels) in the histogram near 255 (Fig 2B). Figure 3 plots MAX_SD at three pupil diameters and increasing exposure time including data from saturated images (Figs 3A-3C) and without saturated images (Figs 3D-3F). When the regression analysis included saturated images (see Figs 3A-3C) over all pupils, R 2 is best for the lowest exposure, 100 ms (average R 2 =0.955). R 2 decreased for increasing exposure times

4 Donnelly and Applegate Page 4 DISCUSSION REFERENCES (average 200 ms R 2 =0.925, and average 300 ms R 2 =0.856). If overexposed images are excluded, low to high exposure time caused the data to shift to increased values of MAX_SD for all pupil diameters (see Figs 3D-3F). All coefficients of determination improved and were similar in value once overexposed images were excluded from the analysis (see Figs 3D-3F). The results of this study indicate that the ability of MAX_SD to predict cataract severity or forward scatter in a longitudinal study of nuclear cataract is optimized by avoiding overexposure and maximizing the dynamic range of pixel values in the S/H image at the first visit for each patient. A possible downside of this approach would be if the forward scatter decreased in severity with time, future images will likely be overexposed, for instance, following a therapy for cataract that not only slows down cataract progression but actually causes the cataract to regress. If this is a concern, instead of maximizing the dynamic range at the initial visit, a cushion to prevent overexposure at future visits should be considered in the process to decrease exposure time. In either case, once a particular exposure time is determined for an individual it should be maintained for the duration of the experiment. It is good photographic practice to neither underexpose nor overexpose an image when detailed contrast information is the goal. However, S/H wavefront sensing is relatively insensitive to overexposure and is very sensitive to underexposure. As a result, S/H images are typically overexposed, or if underexposed, image processed to add brightness to the spots. Here we wish to make the point that if good photographic practices are followed (optimize dynamic range without saturation), then scatter detection is optimized at no cost to wavefront analysis. It is useful to note that the rule for optimizing a S/H image for MAX_SD is easy to implement in software such that the user would simply need to take a few (likely one or two) S/H images and let the software adjust exposure time to optimize the image for MAX_SD extraction. The optimization parameters would then be stored in the patient record and on subsequent visits called up for use. In a SHWS, the limiting aperture is the aperture of each lenslet, not the eye's pupil. Consequently, we did not expect pupil size to have a significant impact on MAX_SD, and as predicted, it did not. Exposure time matters when extracting forward scatter metric MAX_SD from a S/H image. By properly choosing exposure time, simulated nuclear cataract is well predicted by the forward scatter metric MAX_SD. Cataract is only one application of this technique. Forward scatter caused by any of the mechanisms described in the introduction can also be measured using MAX_SD. 1. WJ, Donnelly, III; K, Pesudovs; JD, Marsack; EJ, Sarver; Applegate, RA. Quantifying scatter in Shack- Hartmann images to evaluate nuclear cataract. J Refract Surg 2004;20:S515 S522. [PubMed: ] 2. Bohren, C. Scattering by particles. In: Optical Society of America., editor. Handbook of Optics. 2nd ed.. McGrawHill; New York, NY: p D, Regan; DE, Giaschi; Fresco, BB. Measurement of glare sensitivity in cataract patients using lowcontrast letter charts. Ophthalmic Physiol Opt 1993;13: [PubMed: ] 4. PR, Herse; Bedell, HE. Contrast sensitivity for letter and grating targets under various stimulus conditions. Optom Vis Sci 1989;66: [PubMed: ] 5. van den Berg TJ, IJspeert JK. Clinical assessment of intraocular stray light. Appl Opt 1992;31:1 3.

5 Donnelly and Applegate Page 5 6. van Meeteren A, Vos JJ. Resolution and contrast sensitivity at low luminances. Vision Res 1972;12: [PubMed: ] 7. de Waard PW, JK IJspeert, van den Berg TJ, de Jong PT. Intraocular light scattering in age-related cataracts. Invest Ophthalmol Vis Sci 1992;33: [PubMed: ] 8. LT, Chylack, Jr; JK, Wolfe; DM, Singer; MC, Leske; MA, Bullimore; IL, Bailey; J, Friend; D, McCarthy; Wu, SY. The Lens Opacities Classification System III. The Longitudinal Study of Cataract Study Group. Arch Ophthalmol 1993;111: [PubMed: ] 9. FA, Bettelheim; Ali, S. Light scattering of normal human lens. III. Relationship between forward and back scatter of whole excised lenses. Exp Eye Res 1985;41:1 9. [PubMed: ] 10. DB, Elliott; Bullimore, MA. Assessing the reliability, discriminative ability, and validity of disability glare tests. Invest Ophthalmol Vis Sci 1993;34: [PubMed: ] 11. Brown N. Quantitative slit-image photography of the lens. Trans Ophthalmol Soc U K 1972;92: [PubMed: ] 12. Hockwin O. Cataract classification. Doc Ophthalmol 1994;1995: Elliott DB. Contrast sensitivity decline with ageing: a neural or optical phenomenon? Ophthalmic Physiol Opt 1987;7: [PubMed: ] 14. Whitaker D, Steen R, Elliott DB. Light scatter in the normal young, elderly, and cataractous eye demonstrates little wavelength dependency. Optom Vis Sci 1993;70: [PubMed: ] 15. Thibos LN, Hong X. Clinical applications of the Shack-Hartmann aberrometer. Optom Vis Sci 1999;76: [PubMed: ] 16. Applegate RA, Thibos LN. Localized measurement of scatter due to cataract. Invest Ophthalmol Vis Sci 2000;41:S3.Abstract Arnulf A, Dupuy O. The transmission of contrasts by the optical system of the eye and the retinal thresholds of contrast. Comptes Rendus Hebdomadaires des Seances 1960;250: Campbell FW, Green DG. Optical and retinal factors affecting visual resolution. J Physiol 1965;181: [PubMed: ] 19. Cox MJ, Atchison DA, Scott DH. Scatter and its implications for the measurement of optical image quality in human eyes. Optom Vis Sci 2003;80: [PubMed: ] 20. Glasser A, Campbell MC. Presbyopia and the optical changes in the human crystalline lens with age. Vision Res 1998;38: [PubMed: ] 21. Roorda A, Bobier WR, Campbell MC. An infrared eccentric photo-optometer. Vision Res 1998;38: [PubMed: ]

6 Donnelly and Applegate Page 6 Figure 1. The physical eye model. This assembly picture was used to model a human eye with various levels of nuclear cataract. The model mounts to the front of the SHWS. Left to right is a Lambertian reflector acting as the retina, a cuvette filled with microsphere solution acting as lens cataract, a sliding adjustable pupil, and a plano-convex lens as the main focusing optic.

7 Donnelly and Applegate Page 7 Figure 2. S/H image histograms and respective S/H images. A, B) Pixel intensity histograms are plotted for C, D) two S/H images. The highest quantity in any S/H image will be near 0 or black (1st peak) corresponding to the black background. The next highest quantity is for the pixel value corresponding to the background level within the pupil (2nd peak). 1 With saturation, there is a 3rd peak in quantity of bright pixels near 255 exceeding the 2nd peak (see 2A). Unsaturated S/H images have no 3rd peak (see 2B). The existence or absence of a 3rd peak was used as a criterion to automatically detect lenslet PSF saturation in a S/H image.

8 Donnelly and Applegate Page 8 Figure 3. MAX_SD regressed against cataract level (square root microsphere solution). Pupil diameters were 5, 7, and 9 mm (solid circles, open circles, and solid triangles, respectively) at 100, 200, and 300 ms. A-C) Graphs contain some data points derived from overexposed (saturated) images. D-F) Graphs have data points derived from saturated images removed. The regressions that contain points derived from overexposed images have R 2 that decrease with increasing exposure time. Without saturation, slopes between exposure times (D-F) remain similar, indicating that if MAX_SD is normalized such that the y intercept is 1 then each normalized value would correspond to a given level of cataract severity.

Normal Wavefront Error as a Function of Age and Pupil Size

Normal Wavefront Error as a Function of Age and Pupil Size RAA Normal Wavefront Error as a Function of Age and Pupil Size Raymond A. Applegate, OD, PhD Borish Chair of Optometry Director of the Visual Optics Institute College of Optometry University of Houston

More information

4th International Congress of Wavefront Sensing and Aberration-free Refractive Correction ADAPTIVE OPTICS FOR VISION: THE EYE S ADAPTATION TO ITS

4th International Congress of Wavefront Sensing and Aberration-free Refractive Correction ADAPTIVE OPTICS FOR VISION: THE EYE S ADAPTATION TO ITS 4th International Congress of Wavefront Sensing and Aberration-free Refractive Correction (Supplement to the Journal of Refractive Surgery; June 2003) ADAPTIVE OPTICS FOR VISION: THE EYE S ADAPTATION TO

More information

This is the author s version of a work that was submitted/accepted for publication in the following source:

This is the author s version of a work that was submitted/accepted for publication in the following source: This is the author s version of a work that was submitted/accepted for publication in the following source: Atchison, David A. & Mathur, Ankit (2014) Effects of pupil center shift on ocular aberrations.

More information

ORIGINAL ARTICLE. Metrics of Retinal Image Quality Predict Visual Performance in Eyes With 20/17 or Better Visual Acuity

ORIGINAL ARTICLE. Metrics of Retinal Image Quality Predict Visual Performance in Eyes With 20/17 or Better Visual Acuity 1040-5488/06/8309-0635/0 VOL. 83, NO. 9, PP. 635 640 OPTOMETRY AND VISION SCIENCE Copyright 2006 American Academy of Optometry ORIGINAL ARTICLE Metrics of Retinal Image Quality Predict Visual Performance

More information

Effects of Pupil Center Shift on Ocular Aberrations

Effects of Pupil Center Shift on Ocular Aberrations Visual Psychophysics and Physiological Optics Effects of Pupil Center Shift on Ocular Aberrations David A. Atchison and Ankit Mathur School of Optometry & Vision Science and Institute of Health & Biomedical

More information

Basics Of Retinal Image Quality

Basics Of Retinal Image Quality Slide 2 Basics Of Retinal Image Quality Slide 3 The optics of the eye are the first stage of vision. It is an extremely important stage but not the only stage. Slide 4 Broadly There Are Two Components

More information

PERSPECTIVE THE PRESENCE OF OPTICAL ABERRATIONS THAT BLUR. Making Sense Out of Wavefront Sensing

PERSPECTIVE THE PRESENCE OF OPTICAL ABERRATIONS THAT BLUR. Making Sense Out of Wavefront Sensing PERSPECTIVE Making Sense Out of Wavefront Sensing JAY S. PEPOSE, MD, PHD AND RAYMOND A. APPLEGATE, OD, PHD THE PRESENCE OF OPTICAL ABERRATIONS THAT BLUR retinal images were the subject of popular lectures

More information

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert University of Groningen Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert IMPORTANT NOTE: You are advised to consult the publisher's

More information

Three-dimensional relationship between high-order root-mean-square wavefront error, pupil diameter, and aging

Three-dimensional relationship between high-order root-mean-square wavefront error, pupil diameter, and aging 578 J. Opt. Soc. Am. A/ Vol. 24, No. 3/ March 2007 Applegate et al. Three-dimensional relationship between high-order root-mean-square wavefront error, pupil diameter, and aging Raymond A. Applegate, William

More information

Contrast sensitivity in the presence of a glare light. Theoretical concepts and preliminary clinical studies. L.-E. Paulsson and J.

Contrast sensitivity in the presence of a glare light. Theoretical concepts and preliminary clinical studies. L.-E. Paulsson and J. Contrast sensitivity in the presence of a glare light Theoretical concepts and preliminary clinical studies L.-E. Paulsson and J. Sjostrand A method is presented for quantitative measurements of the glare

More information

10/25/2017. Financial Disclosures. Do your patients complain of? Are you frustrated by remake after remake? What is wavefront error (WFE)?

10/25/2017. Financial Disclosures. Do your patients complain of? Are you frustrated by remake after remake? What is wavefront error (WFE)? Wavefront-Guided Optics in Clinic: Financial Disclosures The New Frontier November 4, 2017 Matthew J. Kauffman, OD, FAAO, FSLS STAPLE Program Soft Toric and Presbyopic Lens Education Gas Permeable Lens

More information

Development of a Calibration Standard for Spherical Aberration

Development of a Calibration Standard for Spherical Aberration Development of a Calibration Standard for David C. Compertore, Filipp V. Ignatovich, Matthew E. Herbrand, Michael A. Marcus, Lumetrics, Inc. 1565 Jefferson Road, Rochester, NY (United States) ABSTRACT

More information

Vision Research at. Validation of a Novel Hartmann-Moiré Wavefront Sensor with Large Dynamic Range. Wavefront Science Congress, Feb.

Vision Research at. Validation of a Novel Hartmann-Moiré Wavefront Sensor with Large Dynamic Range. Wavefront Science Congress, Feb. Wavefront Science Congress, Feb. 2008 Validation of a Novel Hartmann-Moiré Wavefront Sensor with Large Dynamic Range Xin Wei 1, Tony Van Heugten 2, Nikole L. Himebaugh 1, Pete S. Kollbaum 1, Mei Zhang

More information

Raise your expectations. Deliver theirs.

Raise your expectations. Deliver theirs. 66 EXTENDED RANGE OF VISION MONOFOCAL-LIKE DISTANCE Raise your expectations. Deliver theirs. Now you can give your patients the best of both worlds with the first and only hybrid designed monofocal-multifocal

More information

Repeatability of measurements with a double-pass system

Repeatability of measurements with a double-pass system ARTICLE Repeatability of measurements with a double-pass system Alain Saad, MD, Marc Saab, MD, Damien Gatinel, MD, PhD PURPOSE: To evaluate the repeatability of measurements with a double-pass system.

More information

Customized Correction of Wavefront Aberrations in Abnormal Human Eyes by Using a Phase Plate and a Customized Contact Lens

Customized Correction of Wavefront Aberrations in Abnormal Human Eyes by Using a Phase Plate and a Customized Contact Lens Journal of the Korean Physical Society, Vol. 49, No. 1, July 2006, pp. 121 125 Customized Correction of Wavefront Aberrations in Abnormal Human Eyes by Using a Phase Plate and a Customized Contact Lens

More information

Aberrations and Visual Performance: Part I: How aberrations affect vision

Aberrations and Visual Performance: Part I: How aberrations affect vision Aberrations and Visual Performance: Part I: How aberrations affect vision Raymond A. Applegate, OD, Ph.D. Professor and Borish Chair of Optometry University of Houston Houston, TX, USA Aspects of this

More information

Bias errors in PIV: the pixel locking effect revisited.

Bias errors in PIV: the pixel locking effect revisited. Bias errors in PIV: the pixel locking effect revisited. E.F.J. Overmars 1, N.G.W. Warncke, C. Poelma and J. Westerweel 1: Laboratory for Aero & Hydrodynamics, University of Technology, Delft, The Netherlands,

More information

Wavefront Aberrations in Eyes With Acrysof Monofocal Intraocular Lenses

Wavefront Aberrations in Eyes With Acrysof Monofocal Intraocular Lenses Wavefront Aberrations in Eyes With Acrysof Monofocal Intraocular Lenses Prema Padmanabhan, MS; Geunyoung Yoon, PhD; Jason Porter, PhD; Srinivas K. Rao, FRCSEd; Roy J, MSc; Mitalee Choudhury, BS ABSTRACT

More information

In this issue of the Journal, Oliver and colleagues

In this issue of the Journal, Oliver and colleagues Special Article Refractive Surgery, Optical Aberrations, and Visual Performance Raymond A. Applegate, OD, PhD; Howard C. Howland,PhD In this issue of the Journal, Oliver and colleagues report that photorefractive

More information

Ocular Shack-Hartmann sensor resolution. Dan Neal Dan Topa James Copland

Ocular Shack-Hartmann sensor resolution. Dan Neal Dan Topa James Copland Ocular Shack-Hartmann sensor resolution Dan Neal Dan Topa James Copland Outline Introduction Shack-Hartmann wavefront sensors Performance parameters Reconstructors Resolution effects Spot degradation Accuracy

More information

Explanation of Aberration and Wavefront

Explanation of Aberration and Wavefront Explanation of Aberration and Wavefront 1. What Causes Blur? 2. What is? 4. What is wavefront? 5. Hartmann-Shack Aberrometer 6. Adoption of wavefront technology David Oh 1. What Causes Blur? 2. What is?

More information

Choices and Vision. Jeffrey Koziol M.D. Friday, December 7, 12

Choices and Vision. Jeffrey Koziol M.D. Friday, December 7, 12 Choices and Vision Jeffrey Koziol M.D. How does the eye work? What is myopia? What is hyperopia? What is astigmatism? What is presbyopia? How the eye works Light rays enter the eye through the clear cornea,

More information

phone extn.3662, fax: , nitt.edu ABSTRACT

phone extn.3662, fax: , nitt.edu ABSTRACT Analysis of Refractive errors in the human eye using Shack Hartmann Aberrometry M. Jesson, P. Arulmozhivarman, and A.R. Ganesan* Department of Physics, National Institute of Technology, Tiruchirappalli

More information

Customized intraocular lenses

Customized intraocular lenses Customized intraocular lenses Challenges and limitations Achim Langenbucher, Simon Schröder & Timo Eppig Customized IOL what does this mean? Aspherical IOL Diffractive multifocal IOL Spherical IOL Customized

More information

Optics of the crystalline lens and accommodative response

Optics of the crystalline lens and accommodative response Basic Optics Course, Maastricht 2017 Optics of the crystalline lens and accommodative response Rafael Navarro* *No financial interest 1. Optics of the lens Biconvex lens with complex inner structure Simulation

More information

2mm pupil. (12) Patent Application Publication (10) Pub. No.: US 2006/ A1. (19) United States. (43) Pub. Date: Sep. 14, 2006.

2mm pupil. (12) Patent Application Publication (10) Pub. No.: US 2006/ A1. (19) United States. (43) Pub. Date: Sep. 14, 2006. (19) United States (12) Patent Application Publication (10) Pub. No.: US 2006/0203198A1 Liang US 20060203198A1 (43) Pub. Date: Sep. 14, 2006 (54) (75) (73) (21) (22) (60) ALGORTHMS AND METHODS FOR DETERMINING

More information

Choices and Vision. Jeffrey Koziol M.D. Thursday, December 6, 12

Choices and Vision. Jeffrey Koziol M.D. Thursday, December 6, 12 Choices and Vision Jeffrey Koziol M.D. How does the eye work? What is myopia? What is hyperopia? What is astigmatism? What is presbyopia? How the eye works How the Eye Works 3 How the eye works Light rays

More information

MEASURING AND MODELLING FORWARD LIGHT SCATTERING IN THE HUMAN EYE

MEASURING AND MODELLING FORWARD LIGHT SCATTERING IN THE HUMAN EYE MEASURING AND MODELLING FORWARD LIGHT SCATTERING IN THE HUMAN EYE A thesis submitted to The University of Manchester, for the degree of Doctor of Philosophy, in the Faculty of Life Sciences. 2015 Pablo

More information

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert University of Groningen Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert IMPORTANT NOTE: You are advised to consult the publisher's

More information

Ron Liu OPTI521-Introductory Optomechanical Engineering December 7, 2009

Ron Liu OPTI521-Introductory Optomechanical Engineering December 7, 2009 Synopsis of METHOD AND APPARATUS FOR IMPROVING VISION AND THE RESOLUTION OF RETINAL IMAGES by David R. Williams and Junzhong Liang from the US Patent Number: 5,777,719 issued in July 7, 1998 Ron Liu OPTI521-Introductory

More information

NOW. Approved for NTIOL classification from CMS Available in Quar ter Diopter Powers. Accommodating. Aberration Free. Aspheric.

NOW. Approved for NTIOL classification from CMS Available in Quar ter Diopter Powers. Accommodating. Aberration Free. Aspheric. NOW Approved for NTIOL classification from CMS Available in Quar ter Diopter Powers Accommodating. Aberration Free. Aspheric. Accommodation Meets Asphericity in AO Merging Innovation & Proven Design The

More information

Clinical Update for Presbyopic Lens Options

Clinical Update for Presbyopic Lens Options Clinical Update for Presbyopic Lens Options Gregory D. Searcy, M.D. Erdey Searcy Eye Group Columbus, Ohio The Problem = Spherical Optics Marginal Rays Spherical IOL Light Rays Paraxial Rays Spherical Aberration

More information

Study of self-interference incoherent digital holography for the application of retinal imaging

Study of self-interference incoherent digital holography for the application of retinal imaging Study of self-interference incoherent digital holography for the application of retinal imaging Jisoo Hong and Myung K. Kim Department of Physics, University of South Florida, Tampa, FL, US 33620 ABSTRACT

More information

ORIGINAL ARTICLES. Image Metrics for Predicting Subjective Image Quality

ORIGINAL ARTICLES. Image Metrics for Predicting Subjective Image Quality 1040-5488/05/8205-0358/0 VOL. 82, NO. 5, PP. 358 369 OPTOMETRY AND VISION SCIENCE Copyright 2005 American Academy of Optometry ORIGINAL ARTICLES Image Metrics for Predicting Subjective Image Quality LI

More information

Optics of Wavefront. Austin Roorda, Ph.D. University of Houston College of Optometry

Optics of Wavefront. Austin Roorda, Ph.D. University of Houston College of Optometry Optics of Wavefront Austin Roorda, Ph.D. University of Houston College of Optometry Geometrical Optics Relationships between pupil size, refractive error and blur Optics of the eye: Depth of Focus 2 mm

More information

An Automatic System for Classification of Nuclear Sclerosis from Slit-Lamp Photographs

An Automatic System for Classification of Nuclear Sclerosis from Slit-Lamp Photographs An Automatic System for Classification of Nuclear Sclerosis from Slit-Lamp Photographs Shaohua Fan 1, Charles R. Dyer 1, Larry Hubbard 2, Barbara Klein 2 {shaohua, dyer}@cs.wisc.edu, hubbard@rc.ophth.wisc.edu,

More information

HOYA aspherical IOL with ABC (Aspheric Balanced Curve) Design

HOYA aspherical IOL with ABC (Aspheric Balanced Curve) Design HOYA aspherical IOL with ABC (Aspheric Balanced Curve) Design Contents Basics of asphericity Visual quality and aspheric IOL Features of HOYA ABC Design 2 What is asphericity? Deviating from the spherical

More information

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert

Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert University of Groningen Retinal stray light originating from intraocular lenses and its effect on visual performance van der Mooren, Marie Huibert IMPORTANT NOTE: You are advised to consult the publisher's

More information

2 The First Steps in Vision

2 The First Steps in Vision 2 The First Steps in Vision 2 The First Steps in Vision A Little Light Physics Eyes That See light Retinal Information Processing Whistling in the Dark: Dark and Light Adaptation The Man Who Could Not

More information

Corneal Asphericity and Retinal Image Quality: A Case Study and Simulations

Corneal Asphericity and Retinal Image Quality: A Case Study and Simulations Corneal Asphericity and Retinal Image Quality: A Case Study and Simulations Seema Somani PhD, Ashley Tuan OD, PhD, and Dimitri Chernyak PhD VISX Incorporated, 3400 Central Express Way, Santa Clara, CA

More information

What is Wavefront Aberration? Custom Contact Lenses For Vision Improvement Are They Feasible In A Disposable World?

What is Wavefront Aberration? Custom Contact Lenses For Vision Improvement Are They Feasible In A Disposable World? Custom Contact Lenses For Vision Improvement Are They Feasible In A Disposable World? Ian Cox, BOptom, PhD, FAAO Distinguished Research Fellow Bausch & Lomb, Rochester, NY Acknowledgements Center for Visual

More information

The reduction in photopic contrast sensitivity with age 1 3

The reduction in photopic contrast sensitivity with age 1 3 Age-Related Changes in Monochromatic Wave Aberrations of the Human Eye James S. McLellan, 1 Susana Marcos, 1,2 and Stephen A. Burns 1 PURPOSE. To investigate the relations between age and the optical aberrations

More information

FEATURE ARTICLE ON LINE. Uncorrected Wavefront Error and Visual Performance During RGP Wear in Keratoconus

FEATURE ARTICLE ON LINE. Uncorrected Wavefront Error and Visual Performance During RGP Wear in Keratoconus 1040-5488/07/8406-0463/0 VOL. 84, NO. 6, PP. 463 470 OPTOMETRY AND VISION SCIENCE Copyright 2007 American Academy of Optometry FEATURE ARTICLE ON LINE Uncorrected Wavefront Error and Visual Performance

More information

Optical Performance of Nikon F-Mount Lenses. Landon Carter May 11, Measurement and Instrumentation

Optical Performance of Nikon F-Mount Lenses. Landon Carter May 11, Measurement and Instrumentation Optical Performance of Nikon F-Mount Lenses Landon Carter May 11, 2016 2.671 Measurement and Instrumentation Abstract In photographic systems, lenses are one of the most important pieces of the system

More information

Refractive surgery and other high-tech methods

Refractive surgery and other high-tech methods The Prospects for Perfect Vision Larry N. Thibos, PhD Refractive surgery and other high-tech methods for correcting the optical aberrations of the eye aim to make the eye optically perfect. The notion

More information

Report. Evaluating Diffusion of Light in the Eye by Objective Means Gerald Westheimer and Junzhong Liang

Report. Evaluating Diffusion of Light in the Eye by Objective Means Gerald Westheimer and Junzhong Liang Report Evaluating Diffusion of Light in the Eye by Objective Means Gerald Westheimer and Junzhong Liang Purpose. The authors have developed an index of diffusion that describes the relative spread of light

More information

Impact of scattering and spherical aberration in contrast sensitivity

Impact of scattering and spherical aberration in contrast sensitivity Journal of Vision (2009) 9(3):19, 1 10 http://journalofvision.org/9/3/19/ 1 Impact of scattering and spherical aberration in contrast sensitivity Guillermo M. Pérez Silvestre Manzanera Pablo Artal Laboratorio

More information

In recent years there has been an explosion of

In recent years there has been an explosion of Line of Sight and Alternative Representations of Aberrations of the Eye Stanley A. Klein, PhD; Daniel D. Garcia, PhD ABSTRACT Several methods for representing pupil plane aberrations based on wavefront

More information

Accommodation with higher-order monochromatic aberrations corrected with adaptive optics

Accommodation with higher-order monochromatic aberrations corrected with adaptive optics Chen et al. Vol. 23, No. 1/ January 2006/ J. Opt. Soc. Am. A 1 Accommodation with higher-order monochromatic aberrations corrected with adaptive optics Li Chen Center for Visual Science, University of

More information

Subjective Image Quality Metrics from The Wave Aberration

Subjective Image Quality Metrics from The Wave Aberration Subjective Image Quality Metrics from The Wave Aberration David R. Williams William G. Allyn Professor of Medical Optics Center For Visual Science University of Rochester Commercial Relationship: Bausch

More information

Vision. The eye. Image formation. Eye defects & corrective lenses. Visual acuity. Colour vision. Lecture 3.5

Vision. The eye. Image formation. Eye defects & corrective lenses. Visual acuity. Colour vision. Lecture 3.5 Lecture 3.5 Vision The eye Image formation Eye defects & corrective lenses Visual acuity Colour vision Vision http://www.wired.com/wiredscience/2009/04/schizoillusion/ Perception of light--- eye-brain

More information

Hartmann-Shack sensor ASIC s for real-time adaptive optics in biomedical physics

Hartmann-Shack sensor ASIC s for real-time adaptive optics in biomedical physics Hartmann-Shack sensor ASIC s for real-time adaptive optics in biomedical physics Thomas NIRMAIER Kirchhoff Institute, University of Heidelberg Heidelberg, Germany Dirk DROSTE Robert Bosch Group Stuttgart,

More information

Grading nuclear cataract: reproducibility and validity of a new method

Grading nuclear cataract: reproducibility and validity of a new method Br J Ophthalmol 999;83:59 63 59 Medical Research Council Environmental Epidemiology Unit (University of Southampton), Southampton General Hospital, Southampton N F Hall R P Shier D Phillips Department

More information

Digital Wavefront Sensors Measure Aberrations in Eyes

Digital Wavefront Sensors Measure Aberrations in Eyes Contact: Igor Lyuboshenko contact@phaseview.com Internet: www.phaseview.com Digital Measure Aberrations in Eyes 1 in Ophthalmology...2 2 Analogue...3 3 Digital...5 Figures: Figure 1. Major technology nodes

More information

RAYMOND A. APPLEGATE,

RAYMOND A. APPLEGATE, 1040-5488/03/8001-0015/0 VOL. 80, NO. 1, PP. 15 25 OPTOMETRY AND VISION SCIENCE Copyright 2003 American Academy of Optometry ORIGINAL ARTICLE Comparison of Monochromatic Ocular Aberrations Measured with

More information

Image Modeling of the Human Eye

Image Modeling of the Human Eye Image Modeling of the Human Eye Rajendra Acharya U Eddie Y. K. Ng Jasjit S. Suri Editors ARTECH H O U S E BOSTON LONDON artechhouse.com Contents Preface xiiii CHAPTER1 The Human Eye 1.1 1.2 1. 1.4 1.5

More information

Accuracy and Precision of Objective Refraction from Wavefront Aberrations

Accuracy and Precision of Objective Refraction from Wavefront Aberrations Accuracy and Precision of Objective Refraction from Wavefront Aberrations Larry N. Thibos Arthur Bradley Raymond A. Applegate School of Optometry, Indiana University, Bloomington, IN, USA School of Optometry,

More information

Basic Principles of the Surgical Microscope. by Charles L. Crain

Basic Principles of the Surgical Microscope. by Charles L. Crain Basic Principles of the Surgical Microscope by Charles L. Crain 2006 Charles L. Crain; All Rights Reserved Table of Contents 1. Basic Definition...3 2. Magnification...3 2.1. Illumination/Magnification...3

More information

Transferring wavefront measurements to ablation profiles. Michael Mrochen PhD Swiss Federal Institut of Technology, Zurich IROC Zurich

Transferring wavefront measurements to ablation profiles. Michael Mrochen PhD Swiss Federal Institut of Technology, Zurich IROC Zurich Transferring wavefront measurements to ablation profiles Michael Mrochen PhD Swiss Federal Institut of Technology, Zurich IROC Zurich corneal ablation Calculation laser spot positions Centration Calculation

More information

Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes

Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes Bio-Medical Materials and Engineering 24 (2014) 3073 3081 DOI 10.3233/BME-141129 IOS Press 3073 Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes Yi

More information

*Simulated vision. **Individual results may vary and are not guaranteed. Visual Performance When It s Needed Most

*Simulated vision. **Individual results may vary and are not guaranteed. Visual Performance When It s Needed Most Simulated vision. Individual results may vary and are not guaranteed. Visual Performance When It s Needed Most The aspheric design of the AcrySof IQ IOL results in improved clarity and image quality. The

More information

Calculated impact of higher-order monochromatic aberrations on retinal image quality in a population of human eyes: erratum

Calculated impact of higher-order monochromatic aberrations on retinal image quality in a population of human eyes: erratum ERRATA Calculated impact of higher-order monochromatic aberrations on retinal image quality in a population of human eyes: erratum Antonio Guirao* Laboratorio de Optica, Departamento de Física, Universidad

More information

Confocal Imaging Through Scattering Media with a Volume Holographic Filter

Confocal Imaging Through Scattering Media with a Volume Holographic Filter Confocal Imaging Through Scattering Media with a Volume Holographic Filter Michal Balberg +, George Barbastathis*, Sergio Fantini % and David J. Brady University of Illinois at Urbana-Champaign, Urbana,

More information

Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models Song et al. BMC Ophthalmology (2016) 16:9 DOI 10.1186/s12886-016-0184-6 RESEARCH ARTICLE Open Access Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models Hui

More information

Improving Lifestyle Vision. with Small Aperture Optics

Improving Lifestyle Vision. with Small Aperture Optics Improving Lifestyle Vision with Small Aperture Optics The Small Aperture Premium Lens Solution The IC-8 small aperture intraocular lens (IOL) is a revolutionary lens that extends depth of focus by combining

More information

Population study of the variation in monochromatic aberrations of the normal human eye over the central visual field

Population study of the variation in monochromatic aberrations of the normal human eye over the central visual field Population study of the variation in monochromatic aberrations of the normal human eye over the central visual field Matthew T. Sheehan a, Alexander V. Goncharov b, Veronica M. O Dwyer a, Vincent Toal

More information

Degradation of vision through a simulated cataract. Joel L. Zuckerman, David Miller, William Dyes, and Michael Keller

Degradation of vision through a simulated cataract. Joel L. Zuckerman, David Miller, William Dyes, and Michael Keller Degradation of vision through a simulated cataract Joel L. Zuckerman, David Miller, William Dyes, and Michael Keller Most cataracts, apart from the dense nuclear sclerotic type, interfere with vision by

More information

Exam 3--PHYS 151--S15

Exam 3--PHYS 151--S15 Name: Class: Date: Exam 3--PHYS 151--S15 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Consider this diagram of the eye and answer the following questions.

More information

ORIGINAL ARTICLE. Visual Acuity and Optical Parameters in Progressive-Power Lenses. ELOY A. VILLEGAS, OD, and PABLO ARTAL, PhD

ORIGINAL ARTICLE. Visual Acuity and Optical Parameters in Progressive-Power Lenses. ELOY A. VILLEGAS, OD, and PABLO ARTAL, PhD 1040-5488/06/8309-0672/0 VOL. 83, NO. 9, PP. 672 681 OPTOMETRY AND VISION SCIENCE Copyright 2006 American Academy of Optometry ORIGINAL ARTICLE Visual Acuity and Optical Parameters in Progressive-Power

More information

Tutorial: Thermal Modeling in Zemax

Tutorial: Thermal Modeling in Zemax Tutorial: Thermal Modeling in Zemax Heidi Warriner, Opti 521, 10-31-2010 Contents Introduction...2 Design Parameters...2 Analytical Approach...3 Zemax Approach...5 Acrylic Lens and Tube at 20 C...5 Acrylic

More information

WaveMaster IOL. Fast and accurate intraocular lens tester

WaveMaster IOL. Fast and accurate intraocular lens tester WaveMaster IOL Fast and accurate intraocular lens tester INTRAOCULAR LENS TESTER WaveMaster IOL Fast and accurate intraocular lens tester WaveMaster IOL is a new instrument providing real time analysis

More information

ORIGINAL ARTICLE. Correlation between Optical and Psychophysical Parameters as a Function of Defocus

ORIGINAL ARTICLE. Correlation between Optical and Psychophysical Parameters as a Function of Defocus 1040-5488/02/7901-0001/0 VOL. 79, NO. 1, PP. 60-67 OPTOMETRY AND VISION SCIENCE Copyright 2002 American Academy of Optometry A schematic view of the apparatus used is shown in Fig. 1. It is a double-pass

More information

Comparison of higher order aberrations with spherical and aspheric IOLs compared to normal phakic eyes

Comparison of higher order aberrations with spherical and aspheric IOLs compared to normal phakic eyes European Journal of Ophthalmology / Vol. 18 no. 5, 2008 / pp. 728-732 Comparison of higher order aberrations with spherical and aspheric IOLs compared to normal phakic eyes M. RĘKAS, K. KRIX-JACHYM, B.

More information

Some of the important topics needed to be addressed in a successful lens design project (R.R. Shannon: The Art and Science of Optical Design)

Some of the important topics needed to be addressed in a successful lens design project (R.R. Shannon: The Art and Science of Optical Design) Lens design Some of the important topics needed to be addressed in a successful lens design project (R.R. Shannon: The Art and Science of Optical Design) Focal length (f) Field angle or field size F/number

More information

OCULAR MEDIA* PHOTOGRAPHIC RECORDING OF OPACITIES OF THE. development by the control of diabetes, the supply of a deficient hormone

OCULAR MEDIA* PHOTOGRAPHIC RECORDING OF OPACITIES OF THE. development by the control of diabetes, the supply of a deficient hormone Brit. J. Ophthal. (1955) 39, 85. PHOTOGRAPHIC RECORDING OF OPACITIES OF THE OCULAR MEDIA* BY E. F. FINCHAM Institute of Ophthalmology, University of London THE value of photography for recording pathological

More information

Ocular Scatter. Rayleigh Scattering

Ocular Scatter. Rayleigh Scattering Ocular Scatter The are several sources of stray light in the eye including the cornea, transmission through the iris and the crystalline lens. Cornea tends to have Rayleigh Scatter Lens follows inverse

More information

Theoretical modeling and evaluation of the axial resolution of the adaptive optics scanning laser ophthalmoscope

Theoretical modeling and evaluation of the axial resolution of the adaptive optics scanning laser ophthalmoscope Journal of Biomedical Optics 9(1), 132 138 (January/February 2004) Theoretical modeling and evaluation of the axial resolution of the adaptive optics scanning laser ophthalmoscope Krishnakumar Venkateswaran

More information

Yokohama City University lecture INTRODUCTION TO HUMAN VISION Presentation notes 7/10/14

Yokohama City University lecture INTRODUCTION TO HUMAN VISION Presentation notes 7/10/14 Yokohama City University lecture INTRODUCTION TO HUMAN VISION Presentation notes 7/10/14 1. INTRODUCTION TO HUMAN VISION Self introduction Dr. Salmon Northeastern State University, Oklahoma. USA Teach

More information

Optical Quality of the Eye in Subjects with Normal and Excellent Visual Acuity METHODS. Subjects

Optical Quality of the Eye in Subjects with Normal and Excellent Visual Acuity METHODS. Subjects Optical Quality of the ye in Subjects with Normal and xcellent Visual Acuity loy A. Villegas, ncarna Alcón, and Pablo Artal From the Laboratorio de Optica, Departamento de Fisica, Universidad de Murcia,

More information

BEAM HALO OBSERVATION BY CORONAGRAPH

BEAM HALO OBSERVATION BY CORONAGRAPH BEAM HALO OBSERVATION BY CORONAGRAPH T. Mitsuhashi, KEK, TSUKUBA, Japan Abstract We have developed a coronagraph for the observation of the beam halo surrounding a beam. An opaque disk is set in the beam

More information

Assessing Visual Quality With the Point Spread Function Using the NIDEK OPD-Scan II

Assessing Visual Quality With the Point Spread Function Using the NIDEK OPD-Scan II Assessing Visual Quality With the Point Spread Function Using the NIDEK OPD-Scan II Edoardo A. Ligabue, MD; Cristina Giordano, OD ABSTRACT PURPOSE: To present the use of the point spread function (PSF)

More information

Vision 1. Physical Properties of Light. Overview of Topics. Light, Optics, & The Eye Chaudhuri, Chapter 8

Vision 1. Physical Properties of Light. Overview of Topics. Light, Optics, & The Eye Chaudhuri, Chapter 8 Vision 1 Light, Optics, & The Eye Chaudhuri, Chapter 8 1 1 Overview of Topics Physical Properties of Light Physical properties of light Interaction of light with objects Anatomy of the eye 2 3 Light A

More information

A modified Hartmann Shack aberrometer for measuring stray light in the anterior segment of the human eye

A modified Hartmann Shack aberrometer for measuring stray light in the anterior segment of the human eye Graefes Arch Clin Exp Ophthalmol (013) 51:1967 1977 DOI 10.1007/s00417-013-405-5 CATARACT A modified Hartmann Shack aberrometer for measuring stray light in the anterior segment of the human eye Stefan

More information

Chapter Ray and Wave Optics

Chapter Ray and Wave Optics 109 Chapter Ray and Wave Optics 1. An astronomical telescope has a large aperture to [2002] reduce spherical aberration have high resolution increase span of observation have low dispersion. 2. If two

More information

BAT Brightness Acuity Tester. Product No. BAT Instruction Manual

BAT Brightness Acuity Tester. Product No. BAT Instruction Manual BAT Brightness Acuity Tester Product No. BAT-2000 Instruction Manual INTRODUCTION The Marco BAT Brightness Acuity Tester is a handheld instrument designed for two major visual function tests. 1) Brightness

More information

The Appearance of Images Through a Multifocal IOL ABSTRACT. through a monofocal IOL to the view through a multifocal lens implanted in the other eye

The Appearance of Images Through a Multifocal IOL ABSTRACT. through a monofocal IOL to the view through a multifocal lens implanted in the other eye The Appearance of Images Through a Multifocal IOL ABSTRACT The appearance of images through a multifocal IOL was simulated. Comparing the appearance through a monofocal IOL to the view through a multifocal

More information

ORIGINAL ARTICLE. Vision Evaluation of Eccentric Refractive Correction. LINDA LUNDSTRÖM, PhD, JÖRGEN GUSTAFSSON, OD, PhD, and PETER UNSBO, PhD

ORIGINAL ARTICLE. Vision Evaluation of Eccentric Refractive Correction. LINDA LUNDSTRÖM, PhD, JÖRGEN GUSTAFSSON, OD, PhD, and PETER UNSBO, PhD 1040-5488/07/8411-1046/0 VOL. 84, NO. 11, PP. 1046 1052 OPTOMETRY AND VISION SCIENCE Copyright 2007 American Academy of Optometry ORIGINAL ARTICLE Vision Evaluation of Eccentric Refractive Correction LINDA

More information

WaveMaster IOL. Fast and Accurate Intraocular Lens Tester

WaveMaster IOL. Fast and Accurate Intraocular Lens Tester WaveMaster IOL Fast and Accurate Intraocular Lens Tester INTRAOCULAR LENS TESTER WaveMaster IOL Fast and accurate intraocular lens tester WaveMaster IOL is an instrument providing real time analysis of

More information

Posterior capsule opacification (PCO) is the most frequent

Posterior capsule opacification (PCO) is the most frequent Retroillumination versus Reflected-Light Images in the Photographic Assessment of Posterior Capsule Opacification Monica Camparini, Claudio Macaluso, Luca Reggiani, and Giovanni Maraini PURPOSE. To investigate

More information

Optical Coherence: Recreation of the Experiment of Thompson and Wolf

Optical Coherence: Recreation of the Experiment of Thompson and Wolf Optical Coherence: Recreation of the Experiment of Thompson and Wolf David Collins Senior project Department of Physics, California Polytechnic State University San Luis Obispo June 2010 Abstract The purpose

More information

( ) Deriving the Lens Transmittance Function. Thin lens transmission is given by a phase with unit magnitude.

( ) Deriving the Lens Transmittance Function. Thin lens transmission is given by a phase with unit magnitude. Deriving the Lens Transmittance Function Thin lens transmission is given by a phase with unit magnitude. t(x, y) = exp[ jk o ]exp[ jk(n 1) (x, y) ] Find the thickness function for left half of the lens

More information

Shaping light in microscopy:

Shaping light in microscopy: Shaping light in microscopy: Adaptive optical methods and nonconventional beam shapes for enhanced imaging Martí Duocastella planet detector detector sample sample Aberrated wavefront Beamsplitter Adaptive

More information

STUDY NOTES UNIT I IMAGE PERCEPTION AND SAMPLING. Elements of Digital Image Processing Systems. Elements of Visual Perception structure of human eye

STUDY NOTES UNIT I IMAGE PERCEPTION AND SAMPLING. Elements of Digital Image Processing Systems. Elements of Visual Perception structure of human eye DIGITAL IMAGE PROCESSING STUDY NOTES UNIT I IMAGE PERCEPTION AND SAMPLING Elements of Digital Image Processing Systems Elements of Visual Perception structure of human eye light, luminance, brightness

More information

A Computational Model for Predicting Visual Acuity from Wavefront Aberration Measurements

A Computational Model for Predicting Visual Acuity from Wavefront Aberration Measurements A Computational Model for Predicting Visual Acuity from Wavefront Aberration Measurements by Azadeh Faylienejad A thesis presented to the University of Waterloo in fulfillment of the thesis requirement

More information

AgilEye Manual Version 2.0 February 28, 2007

AgilEye Manual Version 2.0 February 28, 2007 AgilEye Manual Version 2.0 February 28, 2007 1717 Louisiana NE Suite 202 Albuquerque, NM 87110 (505) 268-4742 support@agiloptics.com 2 (505) 268-4742 v. 2.0 February 07, 2007 3 Introduction AgilEye Wavefront

More information

Aberrations Before and After Implantation of an Aspheric IOL

Aberrations Before and After Implantation of an Aspheric IOL Ocular High Order Aberrations Before and After Implantation of an Aspheric IOL Fabrizio I. Camesasca, MD Massimo Vitali, Orthoptist Milan, Italy I have no financial interest to disclose Wavefront Measurement

More information

OPTICAL SYSTEMS OBJECTIVES

OPTICAL SYSTEMS OBJECTIVES 101 L7 OPTICAL SYSTEMS OBJECTIVES Aims Your aim here should be to acquire a working knowledge of the basic components of optical systems and understand their purpose, function and limitations in terms

More information

ORIGINAL ARTICLE. Predicting and Assessing Visual Performance with Multizone Bifocal Contact Lenses. JOY A. MARTIN, OD and AUSTIN ROORDA, PhD

ORIGINAL ARTICLE. Predicting and Assessing Visual Performance with Multizone Bifocal Contact Lenses. JOY A. MARTIN, OD and AUSTIN ROORDA, PhD 1040-5488/03/8012-0812/0 VOL. 80, NO. 12, PP. 812 819 OPTOMETRY AND VISION SCIENCE Copyright 2003 American Academy of Optometry ORIGINAL ARTICLE Predicting and Assessing Visual Performance with Multizone

More information

Lecture 2 Slit lamp Biomicroscope

Lecture 2 Slit lamp Biomicroscope Lecture 2 Slit lamp Biomicroscope 1 Slit lamp is an instrument which allows magnified inspection of interior aspect of patient s eyes Features Illumination system Magnification via binocular microscope

More information