Every Airman a Force Multiplier

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Cone Contrast TestAerospace Ophthalmology

USAF School of Aerospace Medicine711th Human Performance Wing

Cone Contrast Test (CCT)

Every Airman a Force Multiplier

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Hereditary color deficiency 8% of males1 in 200 females

Current tests detect presence of color deficiencyFew tests detect

Type (red, green, blue)Severity of deficiency

Introduction

Every Airman a Force Multiplier

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Based on normal color visionLetters visible to single cone typeIn decreasing steps of visibility(cone contrast)Lowest visiblecone contrast

Cone Contrast Test

Every Airman a Force Multiplier

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Quantifies normal color visionType & severity of hereditary deficiencyAcquired color loss in eye disease

Cone Contrast Test

Every Airman a Force Multiplier

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Red Cone Contrasts

1 V Z N F U2 F V N H P3 R P F D U4 Z E D H P5 H R P E D

5

Every Airman a Force Multiplier

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Green Cone Contrasts

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1 H V R N F2 D R E Z U3 N Z V E P4 Z E D N F5 H R P E D

Every Airman a Force Multiplier

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Blue Cone Contrasts

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1 D R E Z U2 F V N H P3 R P F D U4 N Z V E H5 H R P E D

Every Airman a Force Multiplier

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Hereditary Color Deficiency

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1 V Z N F U2 F V N H P3 R P F D U4 Z E D H P5 H R P E D6 D R E Z U

1 V Z N F U2 F V N H P3 R P F D U4 Z E D H P5 H R P E D6 D R E Z U

1 V Z N F U2 F V N H P3 R P F D U4 Z E D H P5 H R P E D6 D R E Z U

Normal perception Red deficiency

Every Airman a Force Multiplier

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Hereditary Color Deficiency

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Normal perception Green deficiency

1 H V R N F2 D R E Z U3 N Z V E P4 Z E D N F5 H R P E D6 F V N H P

1 H V R N F2 D R E Z U3 N Z V E P4 Z E D N F5 H R P E D6 F V N H P

1 H V R N F2 D R E Z U3 N Z V E P4 Z E D N F5 H R P E D6 F V N H P

1 H V R N F2 D R E Z U3 N Z V E P4 Z E D N F5 H R P E D6 F V N H P

Every Airman a Force Multiplier

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CCT Detects Color Deficiency

0 4

0

25

50

75

100

Cone Contrast Test

CCTScore

Red Green Blue

Hereditary Color Deficiency

mean

+3SD

-3SD

NormalsRed deficientGreen deficient

NormalsRed deficientGreen deficient

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Every Airman a Force Multiplier

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CCT Grades Color Performance

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0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

CCT Score (right Eye)

CCT Score (left Eye)

> 2SD

Normal upper right quadrant

75

75

Green deficiency (n=183)Red deficiency (n=43)Normals (n=92)

In color deficiency and in normals

Every Airman a Force Multiplier

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Acquired Color Deficiency:Eye Disease

Visual Pathway

NormalsRetinaOptic Nerve

Red Green Blue

CCT in Eye Disease

Acquired Color Deficiency

0

25

50

75

100

CCTScore

Cone Contrast Test12

Every Airman a Force Multiplier

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N

V

R

E

U

ZZ Single letter

CCT Different

(random)sequence each time

Prevents memorization

Automated CCT

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Every Airman a Force Multiplier

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Brief Demo of Netbook CCT

Pre-calibrated Netbook with CCT programUser friendly; patient responds with mouseRapid staircase to threshold; automatic scoring

Every Airman a Force Multiplier

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Use Mouse to Select the Letter You See; Computer-Voice Reports Your Response; Letter contrast decreases with

correct response; increases with incorrect response

CCT Task

Every Airman a Force Multiplier

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Program Continues until Red, Green and Blue Tests are given to Right Eye and then Left Eye

(just follow the prompts)

CCT Task

Every Airman a Force Multiplier

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Recent CCT Results

Red Deficient

GreenDeficient

Every Airman a Force Multiplier

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CCT Calibration VerificationUser is Prompted Weekly

When prompted, Plug Spyder3 into Netbook USB Port; Place Spyder3 on Measuring Area as Shown; Select Start; Program will require 3-5 minutes

to check calibration and re-calibrate if not within tolerance.