a new definition of refraction: basics and beyond austin roorda, ph.d. unversity of houston college...
TRANSCRIPT
![Page 1: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/1.jpg)
A New Definition of A New Definition of Refraction:Refraction:
Basics and BeyondBasics and Beyond
Austin Roorda, Ph.D.
Unversity of Houston College of Optometry
![Page 2: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/2.jpg)
First use of Optics as Vision AidsFirst use of Optics as Vision Aids
reading stones from 1000 AD1000 AD
![Page 3: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/3.jpg)
1268 Roger Bacon discussed possibilities of magnification with lenses
Roger Bacon
1284 Salvino D'Armate built the first spectacles which were used as reading glasses
1451 Nicholas of Cusa uses negative lenses to cure myopia (nearsightedness)
Kepler
1604 Kepler describes the optics of near and far sightedness
![Page 4: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/4.jpg)
1748: Benjamin Franklin invents the bifocal lens
1827: Sir George Biddel Airy invents spectacles for astigmatism
![Page 5: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/5.jpg)
RetinoscopyRetinoscopy
![Page 6: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/6.jpg)
PhoropterPhoropter
![Page 7: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/7.jpg)
AutorefractorAutorefractor
![Page 8: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/8.jpg)
Refraction SystemsRefraction Systems
![Page 9: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/9.jpg)
AberrometersAberrometersVISX Wavescan
Summit Autonomous Custom Cornea
B&L Zywave
Wavefront Sciences Complete Optical Analysis System
TraceyTech Tracey 1
![Page 10: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/10.jpg)
What is the Wavefront?What is the Wavefront?
converging beam=
spherical wavefront
parallel beam=
plane wavefront
![Page 11: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/11.jpg)
What is the Wavefront?What is the Wavefront?ideal wavefrontparallel beam
=plane wavefront
defocused wavefront
![Page 12: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/12.jpg)
What is the Wavefront?What is the Wavefront?parallel beam
=plane wavefront
aberrated beam=
irregular wavefront
ideal wavefront
![Page 13: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/13.jpg)
What is the Wavefront?What is the Wavefront?
aberrated beam=
irregular wavefront
diverging beam=
spherical wavefront
ideal wavefront
![Page 14: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/14.jpg)
What is the What is the Wave AberrationWave Aberration??diverging beam
=spherical wavefront wave aberration
![Page 15: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/15.jpg)
-3 -2 -1 0 1 2 3
-3
-2
-1
0
1
2
3
Wavefront Aberration
mm (right-left)
mm
(su
peri
or-in
ferio
r)
Wave Aberration: DefocusWave Aberration: Defocus
![Page 16: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/16.jpg)
Wave Aberration: AstigmatismWave Aberration: Astigmatism
-3 -2 -1 0 1 2 3
-3
-2
-1
0
1
2
3
Wavefront Aberration
mm (right-left)
mm
(su
peri
or-in
ferio
r)
![Page 17: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/17.jpg)
-3 -2 -1 0 1 2 3
-3
-2
-1
0
1
2
3
Wavefront Aberration
mm (right-left)
mm
(su
peri
or-in
ferio
r)
Wave Aberration: ComaWave Aberration: Coma
![Page 18: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/18.jpg)
-3 -2 -1 0 1 2 3
-3
-2
-1
0
1
2
3
Wavefront Aberration
mm (right-left)m
m (
supe
rior
-infe
rior)
Wave Aberration: All TermsWave Aberration: All Terms
![Page 19: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/19.jpg)
![Page 20: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/20.jpg)
How Do We Interpret the How Do We Interpret the Wave Aberrations?Wave Aberrations?
![Page 21: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/21.jpg)
Wave Aberration Surface MapWave Aberration Surface Map
![Page 22: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/22.jpg)
-2 -1 0 1 2
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Wave Aberration Contour MapWave Aberration Contour Map
mm (right-left)
mm
(su
perio
r-in
ferio
r)
![Page 23: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/23.jpg)
Breakdown of Zernike TermsBreakdown of Zernike Terms
-0.5 0 0.5 1 1.5 2123456789
1011121314151617181920
Zer
nik
e te
rmCoefficient value (microns)
astig.defocus
astig.trefoilcomacomatrefoil
spherical aberration
2nd order
3rd order
4th order
5th order
![Page 24: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/24.jpg)
Root Mean SquareRoot Mean Square
2 2 2 22 0 2 12 2 2 3 .......RMS Z Z Z Z
astig
mat
ism te
rm
defo
cus t
erm
astig
mat
ism te
rm
trefo
il ter
m……
![Page 25: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/25.jpg)
Point Spread FunctionPoint Spread Function
![Page 26: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/26.jpg)
Point Spread Function vs. Pupil SizePoint Spread Function vs. Pupil Size
pupil images
followed by
psfs for changing pupil size
1 mm 2 mm 3 mm 4 mm
5 mm 6 mm 7 mm
![Page 27: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/27.jpg)
Simulated ImagesSimulated Images
20/40 letters
20/20 letters
![Page 28: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/28.jpg)
Strehl RatioStrehl Ratio
diffraction-limited PSF
Hdl
Heye
actual PSF
Strehl Ratio = eye
dl
H
H
![Page 29: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/29.jpg)
Modulation Transfer Modulation Transfer FunctionFunction
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 50 100 150
spatial frequency (c/deg)
con
tra
st
Area under the MTF
20/20 20/10
![Page 30: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/30.jpg)
Applications for AberrometryApplications for Aberrometry
![Page 31: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/31.jpg)
Can we Build a Better Can we Build a Better Autorefractor?Autorefractor?
-0.5 0 0.5 1 1.5 2
1
234
567
89
10
111213
141516
171819
20
Ze
rnik
e t
erm
Coefficient value (microns)
astig.
defocus
astig.
trefoil
coma
coma
trefoil
spherical aberration
2nd order
3rd order
4th order
5th order
choose the spectacle
correction that minimizes the
second order Zernike terms
![Page 32: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/32.jpg)
Can we Build a Better Can we Build a Better Autorefractor?Autorefractor?
perf
ect P
SF
choose the spectacle
correction that maximizes the
strehl ratio
defocus/astigmatism
![Page 33: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/33.jpg)
Can we Build a Better Can we Build a Better Autorefractor?Autorefractor?
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
-1.4
-1.2 -1
-0.8
-0.6
-0.4
-0.2 0
0.2
0.4
0.6
0.8 1
Defocus (D)
Are
a un
der
MT
F (
0 -
50 c
/d)
choose the spectacle correction that maximizes the
area under the MTF
![Page 34: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/34.jpg)
Can we Build a Better Can we Build a Better Autorefractor?Autorefractor?
• Challenge– RMS, Strehl, and MTF area are not
correlated
• Solution– population data (Rochester, Indiana)– early results suggest maximizing metrics
like the Strehl ratio works best
![Page 35: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/35.jpg)
Aberrometric RefractionAberrometric Refraction
• conventional autorefractors are
accurate to ~ 0.5 D
• aberrometric autorefractor should
achieve ~ 0.1 D accuracy **
** ± 0.25 D is an acceptable correction error
![Page 36: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/36.jpg)
Diagnosis of High-order Diagnosis of High-order AberrationsAberrations
![Page 37: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/37.jpg)
Post - RKPost - RK Post - LASIKPost - LASIK
![Page 38: A New Definition of Refraction: Basics and Beyond Austin Roorda, Ph.D. Unversity of Houston College of Optometry](https://reader036.vdocuments.mx/reader036/viewer/2022062408/56649ef25503460f94c03a66/html5/thumbnails/38.jpg)
KeratoconusKeratoconus