Wavefront-Guided Contact Lenses: Challenges in Moving from the Laboratory to the Dispensary

Geunyoung Yoon, Ph.D. Assistant Professor

Department of Ophthalmology Center for Visual Science Department of Biomedical Engineering University of Rochester Customized Vision Correction Laboratory http://www.cvs.rochester.edu/yoonlab/ Email: [email protected] Carl Chancy

Ramkumar Kamran Sabesan Luis Ahmad Carvalho, PhD Futoshi Taketani, Seth Lana MD, PhD Pantanelli Nagy

Collaborators: David Williams, Scott MacRae, Krystel Huxlin, Jay Wang; U. of Rochester Martin Banks; UC Berkeley Perry Rosenthal; Boston Foundation for Sight Ian Cox, Ravikumar Sumasundaram, Mohinder Merchea; Bausch & Lomb Impact of the wave aberration on retinal image quality -2.5 -2 -1.5 -1 -0.5 0

-2.5 -2 -1.5 -1 -0.5 0 No correction

0.5 1 1.5 2 2.5 3

0.5 1 1.5 2 2.5 3

Conventional correction

-2.5 -2 -1.5 -1 -0.5 0 + Higher order aberrations correction

0.5 1 1.5 2 2.5 3 Abnormal eyes have much greater amounts of higher-order aberrations compared to normals

6 mm pupil m) µ (

2.0 Coma

coefficient 1.5 Spherical aberration 1.0 Zernike

of 0.5

Trefoil Magnitude

Zernike mode Higher order aberrations have been successfully corrected using adaptive optics and wavefront-guided refractive surgery.

Adaptive Optics Customized refractive surgery

Distorted wavefront

Deformable Plane mirror wavefront Customized optics (phase plates) can also correct the higher order aberration. Low contrast (10%) visual acuity

Correcting 2nd order only Correcting 2nd + higher order

Normal eyes Keratoconus 0.2 20/32 1 20/200

) 20/125 0.1 20/25 0.8

0.6 20/80 0 20/20 logMAR

( 0.4 20/50 -0.1 20/16 0.2 20/32

acuity -0.2 20/12.5 0 20/20

-0.3 20/10 1.2 line improvement -0.2 20/12.5

Visual 3.2 line improvement

-0.4 -0.4 20/8 GY JP MM IC Mean Mild Advanced Mean KC KC Is it feasible to correct the higher order aberration with customized soft contact lenses?

With conventional contact lens

Blurred image

With customized contact lens

Sharp image Higher order aberrations can be generated by customized contact lens.

Design Measurement 3

Wavefront height (µm)

-3 CCL for normal eye for a 6 mm pupil

Manufacturing higher order RMS error = 0.25 µm Correcting the higher order aberration with customized soft contact lenses Normal eye for a 6 mm pupil

8 +3 120 6

With conventional HO rms = Wavefront 100 lens 0.69 µm 4

80 2 height ( 0 60 0

-2

40 µ m) -4

20 HO rms = With customized -6 lens 0.49 µm -8 20 40 60 80 100 120 -3 Correcting the higher order aberration with customized soft contact lenses Keratoconic eyes 6 mm pupil

8 8 8 120 120 120 6 6 6

100 100 100 4 4 4 8

120 2 With 80 80 2 80 2 6 0 0 0 conventional 60 60 60 Wavefront 100 -2 -2 -2 40 40 4 lens 40 -4 -4 -4

20 20 20 -6 -6 -6 80 2

-8 -8 -8 20 40 60 80 100 120 20 40 60 80 100 120 20 40 60 80 100 120 height ( HO rms = 3.07 µm 3.74 µm 1.74 µm 0 60 8 8 8 120 120 120 6 6 6 -2 100 100 100 40 4 4 4 µ m)

80 80 2 80 2 2 -4

With 0 0 0 60 60 20 60 -6 customized -2 -2 -2 40 40 40 -4 -4 -4 lens -8 20 20 20 -6 20 40 60 -680 100 120 -6

-8 -8 -8 20 40 60 80 100 120 20 40 60 80 100 120 20 40 60 80 100 120 HO rms = 1.05 µm 1.07 µm 0.52 µm Improving visual performance with customized contact lenses in keratoconus

6 mm pupil

HighHigh contrast contrast letterletter (100%) (100%)

) 0.8 0.7 2.1 lines improved Conventional 0.6 lens logMAR

( 0.5 CustomizedSeries1 0.4 lensSeries2 0.3 acuity 0.2

Visual acuity (logMAR) 0.1

Visual 0 SC1 MX2 MB3 Subject Subjects Improving visual performance with customized contact lenses in keratoconus

6 mm pupil

Low contrastLow contrast letter (20%) (20%) Conventional

) 0.8 lens 2.1 lines improved 0.7 Customized 0.6 lens logMAR

( 0.5 Series1 0.4 Series2 0.3 acuity 0.2

Visual acuity (logMAR) 0.1

Visual 0 SC1 MX2 MB3 Subject Subjects Challenges to make customized contact lenses correct the higher order aberration better

- Manufacturing error

- Decentration and rotation of lens

- Image quality degradation immediately after blinks

- Tear film uniformity on lens surface

- Temporal changes of the aberration

- ….. Manufacturing error

Design Measurement Manufacturing error

Normal HO rms = 0.25 µm eye

Abnormal eye HO rms = 0.58 µm Dynamic movements of soft contact lens after blinks Horizontal and vertical decentration of soft contact lens after blinks

Advanced keratoconus 600 blink Horizontal decentration 400 m) µ (

200

0

-200 decentration

-400 Lens Vertical decentration -600 0 5 10 15 20 25 30

Time (sec) Rotation of soft contact lens after blinks

Advanced keratoconus 4

3 ) 2

degree 1 (

0

-1 rotation -2

Lens -3

-4 0 5 10 15 20 25 30

Time (sec) Partial vs Full Customization Partially vs Fully customized contact lenses: averaged HO aberration in a normal population

6 mm pupil (n=159 normal eyes) 0.4

0.3 Spherical aberration m)

µ 0.2 (

0.1

0 coefficient -0.1

-0.2

Zernike -0.3

-0.4 5 7 9 11 13 15 17 19 21 Zernike mode Partially vs Fully customized contact lenses: Averaged magnitude of HO aberration in a normal population

m) 6 mm pupil (n=159 normal eyes)

µ 0.4 (

0.35

0.3 Coma coefficient

0.25 Spherical aberration

0.2

Zernike 0.15 of 0.1

0.05

0

Magnitude 5 7 9 11 13 15 17 19 21 Zernike mode Partially vs Fully customized contact lenses

- Aspherical lens correcting averaged spherical aberration

- Customized aspherical lens Correcting individual spherical aberration

- Customized coma lens Correcting individual coma

- Customized aspherical + coma lens Correcting individual spherical aberration and coma

- Fully customized lens Correcting most higher order aberrations Retinal image quality metric: volume MTF (vMTF) under white light condition

1 1

vMTFHO correction vMTFconventional

Modulation transfer 0 0 60 60 Spatial frequency (cycles/deg)

vMTFHO correction Visual benefit = vMTFconventional Theoretical performance of partially customized contact lenses based on white light volume MTF

6 mm pupil (n=159 normal eyes) Without rotation 2.4 2.2 Fully customized 2 SA & coma customized SA customized 1.8 Aspherical 1.6 x Coma customized

Benefit 1.4 1.2 1 Visual 0.8 0.6 0.4 0 200 400 600 800 1000 Magnitude of lens decentration (µm) Theoretical performance of partially customized contact lenses based on white light volume MTF 6 mm pupil (n=159 normal eyes) With 5 degree rotation

2.4 Fully customized 2.2 SA + coma 2 SA customized Aspherical 1.8 x Coma customized 1.6 Benefit 1.4 1.2

Visual 1 0.8 0.6 0.4 0 200 400 600 800 1000 Magnitude of lens decentration (µm) Conclusion

Customized soft contact lens has successfully reduced the ocular higher order aberrations by a factor of 3 in keratoconus.

This reduction in the higher order aberration improved both high and low contrast visual acuity by 2.1 lines on average.

Contact lens movements are the most critical factor that decreases visual benefit.

Partially customized contact lenses are less sensitive to the lens movements. However, achievable visual benefit is smaller than fully customized contact lens in the presence of typical amounts of lens movements. Acknowledgements

Research supported by grants from

NIH/NEI (R01-EY014999) Customized contact lens research NYSTAR CEIS (5-23576)

Research to Prevent Blindness

Finger Lake Eye & Tissue Bank

Bausch & Lomb