FEASIBILITY OF WAVEFRONT FEASIBILITY OF WAVEFRONT DERIVED CUSTOMIZED DERIVED CUSTOMIZED

CONTACT LENS CONTACT LENS CORRECTIONSCORRECTIONS

Ian Cox Ph.D.Ian Cox Ph.D.Bausch & LombBausch & Lomb

GeunyoungGeunyoung Yoon Ph.D.Yoon Ph.D.TaeTae--Moon Moon Jeong Jeong Ph.D.Ph.D.Center for Visual Science,Center for Visual Science,

University of RochesterUniversity of Rochester

Custom Correction of Wavefront

Aberration with Contact Lenses

- What Should We Correct?

Population Spherical Aberration

Population Distribution of Spherical Aberration

Z40 - Spherical Aberration

No

of o

bs

0

6

12

18

24

30

36

42

48

54

60

66

72

78

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2

n = 199

Population Distribution of Spherical Aberration

Z40 - Spherical Aberration

No

of o

bs

0

6

12

18

24

30

36

42

48

54

60

66

72

78

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2

n = 199

+ + + + + - -

Population Spherical Aberration Distribution

Spherical Aberration vs Spherical Rx

Subjective Spherical Error

Sphe

rical

Abe

rrat

ion

(um

)

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2-12 -10 -8 -6 -4 -2 0 2 4 6

n = 199+

+

+

+

+

-

-

Contact Lens Correction of Wavefront Aberration

• Individual Correction of Patient’s • Non-Rotationally Symmetric Aberrations

Issues- Control of Lens Rotation on the Eye- Control of Lens Movement in X&Y Planes- Compensating for Aberrations Induced By Lens Itself

- Processing Technology

Custom Correction of Wavefront

Aberration with Contact Lenses

- What type of Lens Should We Use?

Optimally Fit RGP Lenses

Peripheral Epithelial Staining

Soft Lens Fitting Theory - Negative Pressure Model

SOFT TORIC LENS DESIGN

Prism Ballast Orientation Mechanism

SOFT TORIC LENS ROTATIONAL ORIENTATION

SOFT TORIC LENS ROTATIONAL STABILITY

Custom Correction of Wavefront

Aberration with Soft Contact Lenses

- How to Manufacture?

Modern Lathing Process

2-Axis CNCOscillating Tool PostDiamond Point TurningNo Polishing

Customized Contact Lenses

Lens is Custom Packaged and Delivered to Doctor or Patient

Zywave Measures Wavefront Aberration in Clinicians

Office

Variform Lathe Creates Non-Symmetric Customized Lenses

Correcting Lens Design is Computed Remotely Via Internet

Capability of Lathing Manufacturing TechnologyCapability of Lathing Manufacturing TechnologyModel Eye No Defocus or Astigmatism

Model EyeUncorrected

Model EyeWith Lens

Wavefront Aberration

Point Spread Function

Strehl Ratio = 0.001 Strehl Ratio = 0.012 Strehl Ratio = 0.324

5.7mmPupil

PSF Convolution

Custom Correction of Wavefront

Aberration with Soft Contact Lenses

- Can We Improve Vision?

Correction of the eye’s aberration using phase plate and measurement of visual performance

Eye

Visual stimulus

Phase plate(pupil conjugate)

Laser

CCD

DMDprojector

Artificialpupil

Wavefrontsensor

Visual acuity

Pupilcamera

-0.5

0

0.5

1

1.5

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

2nd order Higher order (3rd ~ 5th) aberrations

Zer

nike

coef

ficie

nt (µ

m)

6mm pupil, GY

Eye

Eye + phase plate

-0.2

-0.1

0

0.1

0.2

0.3

0.4

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Total rms: 1.59 0.25µm2nd rms: 1.54 0.15µmHO rms: 0.38 0.20µm

Subject GY

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

2nd order Higher order (3rd ~ 5th) aberrations

Zer

nike

coef

ficie

nt (µ

m)

6mm pupil, JP

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Eye

Eye + phase plate

Total rms: 0.59 0.24µm2nd rms: 0.49 0.17µmHO rms: 0.33 0.16µm

Subject JP

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

2nd order Higher order (3rd ~ 5th) aberrations

Zer

nike

coef

ficie

nt (µ

m)

Eye

Eye + phase plate6mm pupil, IC

-0.2

-0.1

0

0.1

0.2

0.3

0.4

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Total rms: 0.927 0.24µm2nd rms: 0.785 0.19µmHO rms: 0.49 0.14µm

Subject IC

-1

0

1

2

3

4

5

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

2nd order Higher order (3rd ~ 5th) aberrations

Zer

nike

coef

ficie

nt (µ

m)

-0.4

-0.2

0

0.2

0.4

0.6

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

6mm pupil, MM

Total rms: 4.17 0.35µm2nd rms: 4.12 0.26µmHO rms: 0.65 0.24µm

Eye

Eye + phase plate

Subject MM

-2

-1

0

1

2

3

4

5

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

-2

-1.5

-1

-0.5

0

0.5

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

2nd order Higher order (3rd ~ 5th) aberrations

Zer

nike

coef

ficie

nt (µ

m)

6mm pupil, FE

Total rms: 5.13 0.36µm2nd rms: 4.82 0.28µmHO rms: 1.75 0.18µm

Eye

Eye + phase plate

Subject FE

GY JPSubject IC MM FE

µm µm

Eye

2nd ordercorrected

2nd + higherordercorrected(phase plate)

Eye

2nd ordercorrected

2nd + higherordercorrected(phase plate)

GY JPSubject IC MM FE

1

2

3

4

5

6

0 10 20 30 40 50 600.01

0.1

1

0 10 20 30 40 50 60

Improvement in MTF in Improvement in MTF in normal eyesnormal eyes

MTFsVisual benefit of

correcting higher order aberrations

Spatial frequency (c/deg)

Mod

ulat

ion

tran

sfer

Perfectcorrection

2nd ordercorrection

2nd + higher ordercorrection

6mm pupilAveraged from 5 subjects

Perfect correction2nd order correction

Phase plate correction2nd order correction

Vis

ual b

enef

it

Improvement in visual Improvement in visual acuityacuity in in normal eyesnormal eyes

Subjects

GY JP MM IC FE Mean

Vis

ual a

cuity

(log

MA

R)

20/20

20/16

20/12.5

20/10

Correcting 2nd order only

Correcting 2nd + higher order

20/25

20/32

20/20

20/16

20/12.5

20/10

20/25

20/32

-0.3

-0.2

-0.1

0

0.1

0.2

-0.3

-0.2

-0.1

0

0.1

0.2

GY JP MM IC FE Mean

High contrast (100%) letter Low contrast (10%) letter

SOFT TORIC LENS DESIGNSOFT TORIC LENS DESIGN

Prism Ballast Orientation MechanismPrism Ballast Orientation Mechanism

Incremental Correction of Zernike TermsIncremental Correction of Zernike Terms

1 Patient

Trial Lens Correction (Prism Ballasted Sphere)

1. Sphere only2. Sphere & Spherical Aberration3. 2nd Order Only4. 2ndOrder & Spherical Aberration5. 2nd Order & 3rd Order6. 2nd, 3rd & Spherical Aberration7. 2nd, 3rd, 4th, 5th

Incremental Correction of Zernike TermsIncremental Correction of Zernike TermsUsing Soft Prism Ballasted LensesUsing Soft Prism Ballasted Lenses

Contact Lens Correction of Wavefront Contact Lens Correction of Wavefront Aberration Aberration -- ConclusionConclusion

Technically Feasible for a Large Percentage of the Population Needing Vision Correction

To Be Truly Effective It Requires CustomCorrection of Individual Non-RotationallySymmetric Wavefront Aberrations Up to andIncluding 5th Order Zernike.

0

1

2

3

4

5

6

0

1

2

3

4

5

6

Rm

swav

efro

nt e

rror

(µm

)

The phase plate can effectively correct both lower The phase plate can effectively correct both lower and higher order aberrations in the eye.and higher order aberrations in the eye.

Higher order rmsTotal rms

Subjects

GY JP MM IC FE Mean GY JP MM IC FE Mean

Eye

Eye + phase plate

6mm pupil6mm pupil