Netra at Mobile Health Expo NYC

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Cell Phone-based Optometry Solution The Inverse of Shack-Hartmann Vitor Pamplona eyenetra.com

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Transcript of Netra at Mobile Health Expo NYC

Cell Phone-based Optometry Solution

The Inverse of Shack-Hartmann

Vitor Pamplonaeyenetra.com

Andres Rueda

Thermometer for vision

Collaboration with: Ankit Mohan , Manuel M. Oliveira, Ramesh Raskar

Collaboration with: Ankit Mohan , Manuel M. Oliveira, Ramesh Raskar

Thermometer for vision

6.5 Billion

people

4.5B have a

cell phone

2B have

refractive errors

0.6B have URE

Shack-Hartmann Wavefront Sensor

Expensive; Bulky, Requires trained professionals

Wavefront aberrometer

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Shack-Hartmann Wavefront Sensor

Laser

Sensor MicrolensArray

Planar Wavefront

Spot Diagram

Laser

Sensor

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Displacement = Local Slope

of the Wavefront

Spot Diagram

Shack-Hartmann Wavefront Sensor

NETRA = Inverse of Shack-Hartmann

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Spot Diagram on LCD

Cell Phone Display

Eye Piece

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Spot Diagram on LCD

Inverse of Shack-HartmannUser interactively creates the Spot Diagram

Displace 25 points but 3 parameters

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Spot Diagram on LCD

Inverse of Shack-HartmannUser interactively creates the Spot Diagram

Displace 25 points but 3 parameters

Eye

Relaxed Eye with Myopia

Blurred point

Red pointat infinity

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

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Eye

Relaxed Eye with Myopia

Distinctimage points

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

Pinholes

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Red pointat infinity

Scheiner’s Principle

Eye

Relaxed Eye with Myopia

Virtual red pointat infinity

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

14

A

B

Distinctimage points

Display

Relaxed Eye with Myopia

A

B

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

Virtual red pointat finite distance

Move spots towards each

other

Display

Eye

15

Distinctimage points

B

A

Points overlap

Relaxed Eye with Myopia

Display

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

Eye

Virtual red pointat finite distance

Move spots towards each

other

16

B

A

Points overlap

Relaxed Eye with Myopia

Display

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

Eye

Virtual red pointat finite distance

Move spots towards each

other

17

d

Points overlap

Relaxed Eye with Myopia

perfect vision

myopia

hyperopia

~10cminfinity

Focusing Range

Eye

18

d

d

1

Point at infinity

Interactive Method

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Interactive Method

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Interactive Method

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Interactive Method

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Interactive Method

Farthest Focal Point(myopia, hyperopia, astigmatism) 24

Limitations

• Children

• Ability to align lines

• Resolution is a function of the display DPI

– Samsung Behold II – 160 DPI – 0.35D

– Google Nexus One – 250 DPI – 0.2D

– Apple iPhone 4G – 326 DPI – 0.14D

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Why Now?

0.35um

Confidential 27

NETRA Prototypes Worldwide29 partners in 14 countries.

Clinical Testing Partners

NETRA Team at LVPEI, India

Kenya

Tufts U. (Boston) NETRA vs Manifest Refraction

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

4.00

5.00

-5.00 -3.00 -1.00 1.00 3.00 5.00

Net

ra (D

)

Retinoscopy (D)

13 adults

-7.00

-5.00

-3.00

-1.00

1.00

3.00

5.00

7.00

-7.00 -2.00 3.00

Net

ra (D

)

Retinoscopy (D)

29 adults

LVPEI (India)NETRA vs Retinoscopy

Validation: Side by Side Trials

Preventable Blindness

WHO 2004

Unique, quantitative lens mapping

CATRA: Quantitative Cataract Maps

with: Erick Passos, Jan Zizka, Everett Lawson, Esteban Clua , Manuel M. Oliveira, Ramesh Raskar

Testing the Presence of Cataracts

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Blin

kin

g p

atte

rns

on

Scr

ee

n

Cell Phone Display

Pinhole

Lens

36 years old female with Posterior Sub-Capsular (10%)

CATRA’s Opacity MapSlit-lamp

Retro-illumination

For the Future

• Ophthalmology for Masses– >.5 billion URE. > 2.5 billion RE. -> Devices for all

• Quality of phones (resolution) will increase exponentially

• New features (recently cataracts, next Retinal NETRA)

• Smart phones will take over the market in developing world countries like India in next 5 years.

• Hardware store

NETRAhttp://eyenetra.com

Vitor Pamplona

Photography in 1960s

Illana Tamir

Roboppy

Today, cameras are everywhere

Photo: Derek K. Miller

Photo: Tyler

Photo: John Kannenberg

Corneal TopographerWavefront Aberrometer

Phoropter

Optometry Today

Snellen chartTrial set of lenses Lasers

“point-and-shoot” optometry

Traditional User Driven

Mass-use Devices Scientific Instruments

Phoropter

Snellen chart

Trial lenses

Reading Charts

• Accuracy– Sharpness Estimation is subjective

– Brightness affects results

– Pupil size variation and DoF

• Cost– Trial Lens Set > $150

– Bulky

EHR

DeliveryDiagnosticEyecare

Providers

New Ecosystem

Asynchronous

Medical IT Systems

Retinoscope w/

Lenses

Auto-refracto-

meter

Chart with

Lenses

In-Focus: Focometer Optiopia

Solo-health: EyeSite

NETRA

Technology Shining Light plus lenses

FundusCamera

Moving lenses + target

Moving lenses + target

Reading chart on monitor

Cellphone+ eyepiece

Cost to buy $2,000* ~$10,000 ~$100 ~$495 ~$200 -- $30

Cost per test ~$36 ~$36 ~$5 -- -- -- ~$1

Data capture No Comp. No No No Comp. Phone

Mobility <500g >10Kg 2kg 1kg <5kg >10Kg <100g

Speed Fast Fast Medium Medium -- Fast Fast

Scalability No No No Yes Probably No Yes

Accuracy 0.15 0.15 0.5 0.75 -- -- <0.5

Self evaluation No No Yes Yes Yes Yes Yes

Electricity Req No Yes No No -- Yes No

Astigmatism Yes Yes Yes/No No -- Yes Yes

Network No Yes No No No Yes Yes

Training High High High Medium Medium Low Low

* Phoropter-based: $5,000.00

Needs expert, Moving parts, Shining lasers

Human Eye

Human Eye

Cornea(~40D) Crystalline lens

(10~20D)

Retina

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Human Eye

Human Eye

Cornea(~40D) Crystalline lens

(10~20D)

Retina

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Accommodation

Infinity

Perfect Vision System

Human Eye

Infinity

Subject can focusat infinity

10cm

Normal Vision

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Accommodation Range

Myopia (nearsightedness)

Infinity

Subject cannot focusat far distances

10cm

Normal Vision

Myopia

Wrong focal point

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Accommodation Range

Infinity

Human Eye

Myopia Correction

Infinity

Subject can focusat infinity

10cm

Normal Vision

Myopia

Divergent Lens

Corrected Myopia

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Accommodation Range

Infinity

Human Eye

Hyperopia (farsightedness)

Infinity 10cm

Normal Vision

Myopia

Hyperopia

Wrong focal point

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Accommodation Range

Infinity

Human Eye

Hyperopia Correction

Infinity

Accommodation Range

10cm

Normal Vision

Myopia

Hyperopia

Convergent Lens

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Corrected Hyperopia

Infinity

Human Eye

Refractive Errors and Shifted Range

Perfect vision

Myopia

Hyperopia

10cmInfinity

Need to measure

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1m 33cm Distance

Refractive Errors and Shifted Range

Perfect vision

Myopia

Hyperopia

10cmInfinity

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-10D0D

Diopter = 1/Distance

-3D-1D

1m 33cm

+1D+3D

Distance

Diopter

Astigmatism: angle-dependent refractive error

http://www.elizabethpope.co.uk/eyeinfo/astigmatism.html 56

Astigmatism: angle-dependent refractive error

http://www.elizabethpope.co.uk/eyeinfo/astigmatism.html 57

Astigmatism: angle-dependent refractive error

http://www.elizabethpope.co.uk/eyeinfo/astigmatism.html 58

Refractive Power as a Function of Angle

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Cylinder SphereAxis Cyl.Unknowns:

SCP )(sin(2

Astigmatism

Cross or points may never meet with a 1d search !60

Astigmatism

Lines reduce the problem to a 1d search61

Measuring the Accommodation Range

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Perfect vision

~10cmInfinity

Myopia

Hyperopia

Step 1: Far limit Step 2: Near limit

Measuring the Accommodation Range

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Perfect vision

~10cmInfinity

Myopia

Hyperopia

Step 1: Far limit Step 2: Near limit

Measuring the Accommodation Range

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Perfect vision

~10cmInfinity

Myopia

Hyperopia

Step 1: Far limit Step 2: Near limit

Points overlap

A

B

Display

Virtual Point at the far limit

Relaxed Eye

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Points overlap

A

B

Display

Accommodated Eye

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Virtual pointgetting closer

Move points towardseach other

Subject Accommodates to fix the “blur”

Points overlap

A

B

Display

Accommodated Eye

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Virtual pointgetting closer

Move points towardseach other

Subject Accommodates to fix the “blur”

Points overlap

A

B

Display

Accommodated Eye

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Virtual pointgetting closer

Move points towardseach other

Subject cannot accommodate more than the previous point

Patterns for Alignment Task

Displayed

Subject view

Displayed

Subject view

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Visual Cryptography

A B A B A B A B A B

A B A B A B A B A B

[NaorShamir94]

Patterns for Alignment Task

Displayed

Subject view

Displayed

Subject view

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Visual Cryptography

A B A B A B A B

A B A B A B A B A B

A B

[NaorShamir94]

Summary of Interaction

Farthest Point(myopia, hyperopia, astigmatism)

Nearest Point(presbyopia)

Accommodation Range

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