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

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Raymond McGee
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1 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 Institute (GPLI) Visionary Optics NIH/NEI R01EY (RAA and JDM) Speaker Speaker Speaker Funding Do your patients complain of? Are you frustrated by remake after remake? Difficulty seeing at night Glare Halos Blurring Starburst patterns Double vision/smearing Spec Rx #1: OD: x 170 OS: x 143 Spec Rx #2: OD: x 165 OS: x 140 Spec Rx #3: OD: x 173 OS: x 135 Your patient could be suffering from What is wavefront error (WFE)? Higher order aberrations (HOAs) Difference between the ideal wavefront and the actual wavefront 1

2 Why does wavefront error matter? Tells the prescriber the ideal compensating optical system Determines how much tissue/material to remove at each location Wavefront retarded remove more material Wavefront advanced remove less material Utilize to create Point Spread Function and simulate retinal image Wavefront error Point Spread Function Simulated Visual Acuity Chart Zernike polynomial Classification Representation of ocular aberrations as light waves pass through optical system Three dimensional Infinite number of Zernike functions Lower order aberrations 0, 1 st, and 2 nd order Higher order aberrations 3 rd order and higher Zernike polynomials Zero and 1 st order Double index system Z M N Z = polynomial M = angular frequency (orientation) Sine (-) Cosine (+) N = radial order C = coefficient (magnitude) Generally ignored when measuring monochromatic aberrations Do not affect image quality 0 = piston Adds constant to all locations 1 st order = prism Changes position; not image quality 2

3 Second order Third order and above Defocus and astigmatism Myopia and hyperopia Traditional ophthalmic prescription Comprise 85-92% of total ocular aberrations Z0/2 = Defocus (spherical) Z-2/2 + Z2/2 = cylindrical error Higher order aberrations 3 rd and 4 th order terms most prevalent Coma and spherical aberration most important HOAs Coma Spherical aberration Light rays enter optical system not parallel to optic axis Point source appears distorted Comet-like tail Blurring caused by light from edge of mirror/lens focusing at shorter distance than central light Total high order root mean square Relationship between pupil diameter & age HO RMS Equal to standard deviation of high order wavefront over pupil aperture Computer magnitude of combined Zernike modes Square each Zernike coefficient, add them, then take square root Pupil diameter Total HO RMS WFE varies with pupil diameter Age HO RMS WFE increases with age Increase in WFE may be responsible for some of decrease in acuity with age 3

4 Aberrometer Type of wavefront aberrometers Aka wavefront sensor Measures distortion of light waves as it passes through optical system Red (warm) = positive wavefront Blue (cool) = negative wavefront Hartmann-Shack Tscherning (ray tracing) Hartmann-Shack Tscherning (ray tracing) Outgoing wavefront aberrometer Measures wavefront shape reflected out of eye from foveal point source Best repeatability for total ocular aberrations Ingoing wavefront aberrometer Thin laser beam project into eye Photodector used to determine position of light spot on retina Aberrations cause shift in light spot locations Best repeatability for corneal aberrations Ex. itrace (Tracey Technologies) Aberrations in normal population Aberrations in irregular cornea patients Positive spherical aberration Keratoconus Vertical coma (Z3,-1) Negative vertical coma Trefoil Spherical aberration Central cone = spherical aberration most dominant Decentered cone = vertical coma, trefoil, and spherical aberration 4

5 Aberrations in irregular cornea patients Corneal topography Corneal transplant Trefoil Spherical aberration Measures aberrations caused by anterior corneal surface Placido disk only measures anterior surface aberrations Does not take into account axial length of eye Refractive surgery Lasik conventional treatment RK Lasik Conventional treatment Wavefront-guided Wavefront-optimized PRK Refractive surgery induces HOAs Early Lasik correct defocus Increase in HOAs 6-month post-op Lasik wavefront-guided treatment Lasik wavefront-optimized treatment Customize ablation patterns based on higher and lower-order aberration profiles for individual Reduce preoperative HOAs Use pre-programmed ablation profiles based on population analysis Minimize induction of post-op HOAs 5

$profiler Plus 4 in 1 system Refractive error Corneal topography Keratometer Wavefront aberrations Hartmann-Shack sensor Measures up to 7 th order Zernike aberrations https://www.zeiss.$

6 Spectacles i.scription (Zeiss) izon High Resolution Lenses (Ophthonix Inc.) Z View aberrometer Correct up to 6 th order Non Hartmann-Shack Closed Correct HOAs and provide sharper vision than traditional lenses i.profiler Plus 4 in 1 system Refractive error Corneal topography Keratometer Wavefront aberrations Hartmann-Shack sensor Measures up to 7 th order Zernike aberrations Intraocular lens implants Contact lenses Young individuals, crystalline lens compensates for positive spherical aberration from cornea As age increases, lens provides less (-) spherical aberration correction Aspherica IOLs have become more popular Tecnis Z9000 (Pfizer) First IOP designed to correct HOAs Modified anterior surface Compensates for spherical aberration of cornea Incorporates negative spherical aberration Soft contact lenses Off-the-shelf Customized Gas permeable contact lenses (scleral lenses) Obstacles: Lens movement Rotation Centration Spherical Contact Lenses Off-the-shelf Positive power = induce positive spherical aberration Negative power = induce negative spherical aberration Biofinity Proclear daily disposable PureVision C-Vue Aspheric Single Vision lens (Unilens) WaveTouch (WaveTouch Technologies) Correct spherical aberration Introduced by lens itself Average spherical aberration in human eyes Spherical aberration-correcting lenses Aspheric lenses that reduce aberration produced by lens; large pupil size 6

Soft contact lenses izone by Definition wavefront-guided contact lenses Corrects lower and higher order

high/low contrast visual acuity Four custom lenses Trial lens #1: Full 2 nd to 3 rd order correction #2

improved 0.07 ± 0.06 to -0.08 ± 0.05 (5 mm pupil) Low contrast logmar improved 0.70 ± 0.06 to 0.62 ± 0.

386 µm 84% reduction in LOAs 50% reduction in HOAs 3 keratoconic eyes Compared visual performance of

equivalent to habitual GP corrections Scleral lenses University of Houston College of Optometry 12

7 Soft contact lenses izone by Definition wavefront-guided contact lenses Corrects lower and higher order aberrations One keratoconic eye Moderate keratoconus Habitual lens = SofLens 66 (B+L) Measured photopic high/low contrast visual acuity Four custom lenses Trial lens #1: Full 2 nd to 3 rd order correction #2 & 3: Full 2 nd to 4 th order correction High contrast logmar visual acuity statistically significantly improved 0.07 ± 0.06 to ± 0.05 (5 mm pupil) Low contrast logmar improved 0.70 ± 0.06 to 0.62 ± 0.07 (5 mm pupil) HO RMS levels decreased µm to µm 84% reduction in LOAs 50% reduction in HOAs 3 keratoconic eyes Compared visual performance of custom lens with habitual GP correction Custom WFG soft contact lenses Provided high contrast logmar VA equivalent to habitual GP corrections Scleral lenses University of Houston College of Optometry 12 subjects 8 subjects analyzed 7 eyes (mild corneal ectasia) 8 eyes (moderate ectasia) 1 eye (severe ectasia) 8 weeks non-wfg scleral lens 8 weeks WFG scleral lens 7

8 Scleral lenses LogMAR Non-WFG scleral lens Mean logmar: ± 0.09 (best = -0.19, worst = 0.08) WFG scleral lens Mean logmar: ± 0.11 (best = -0.20, worst = 0.21) Residual HO RMS (5 mm pupil) Non-WFG scleral lens 0.46 ± 0.25µm (0.17µm to 1.17µm) WFG scleral lens 0.27 ± 0.084µm (0.15µm to 0.48µm) THANK YOU mjkauffm@central.uh.edu 8

The Aberration Structure of the Keratoconic Eye

The Aberration Structure of the Keratoconic Eye Geunyoung Yoon, Ph.D. Department of Ophthalmology Center for Visual Science Institute of Optics Department of Biomedical Engineering University of Rochester