Barbara WilhelmSteinbeis Transfer Centre Biomedical Optics and Function Testing at

the University Eye Hospital TübingenDept. Autonomous Nervous System and Safety Studies

Sponsored by and performed at DaimlerChrysler AG, Dept.PWT/PBT, Sindelfingen

EAGOSH, May 2007

B. Wilhelm

MyMy CoCo­­workersworkersWilhelm Durst

MichaelSell

Petra Weckerle

Anja Widmann

andJutta IsenseeHolger Lüdtke

EAGOSH, May 2007

B. Wilhelm

BackgroundBackground

Question: Are there effects of bright lights during day shift?

• DIN EN 12 464– Recommendation of 2500 Lux

in production• Advertisement of light industry

– positive effects on productivity– 5times more light causes 20% higher

productivity• Bright light seems to improve

adaptation to night work

EAGOSH, May 2007

B. Wilhelm

PreparationPreparation ofof thethe studystudyOphthalmolgical screening in

the target group

•visual acuity (near and far)•contrast vision•colour vision•night vision•accommodation•pupil reaction•slit lamp

EAGOSH, May 2007

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EAGOSH, May 2007

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ResultsResults ofof ScreeningScreening

63 workers examined27 were not included in the main trial because of:

12 visual acuity worse than 0,8­ mostly insufficient near correction (own glasses)

1 colour defect4 suspected glaucoma2 insufficient night vision2 diseases of optic nerve and cornea

5 organisatory changes1 younger than 18 years

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B. Wilhelm

Carcass finish E­Class Plant SindelfingenShift group A: 18 –57 years (Median 36 J)Shift group B: 21 –63 year (Median 42 J)

EAGOSH, May 2007

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ConditionsConditions

• fluorescent tubes TypePhilips TLS 80W/865

• three levels– 500 lx– 1500 lx– 2500 lx

• included n=28,– A: 10, B: 18

• complete data n=23– A: 9, B: 14

• estimated sample size– n=18

• Hawthorne­effect control• parameters of evaluation

– visual performance– subjective scales– alertness (PST)

• relevant effect sizes

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ForFor comparisoncomparison

Light intensities

full mooncity roadwork placedirect sun light

1 lx10 lx

500 lx100.000 lx

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StudyStudy designdesign

0

500

1500

2500

Lux

1 2 3 4 5

04.1041

11.1042

18.1043

25.1044

02.1145

08.1146

15.1147

22.1148

29.1149

06.12.200450

6 7 8 9 10 Wochen

DatumWoche

GruppeA B B B A BA A

Messpause

B A AB B AAB

OphthalmologicalScreening

Interruptiondaylight sav­ing time off

Christmas

EAGOSH, May 2007

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MethodsMethods: Visual: Visual AcuityAcuity

ETDRS­Charts

EAGOSH, May 2007

B. Wilhelm

ResultsResults: Visual: Visual AcuityAcuity

Periode/Helligkeit

Seh

schä

rfe b

inok

ular

 95%

CI

1/500 1/1500 1/2500 2/500 2/1500 2/2500

1.0

1.5

2.0

2.5

Helligkeitsdifferenzen

Seh

schä

rfe b

inok

ular

 95%

CI

Diff 1500 Diff 2500 Diff 2500 / 1500­0

.50.

00.

5

PP ­ Sehschärfe binokular

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MethodsMethods:: ColourColour visionvision

FM28

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ResultsResults:: ColourColour VisionVision

Periode/Helligkeit

Farb

test

 Tot

al E

rror S

core

, bin

okul

ar 9

5%C

I

1/500 1/1500 1/2500 2/500 2/1500 2/2500

5010

015

020

0

Helligkeitsdifferenzen

Farb

test

 Tot

al E

rror S

core

, bin

okul

ar 9

5%C

I

Diff 1500 Diff 2500 Diff 2500 / 1500­1

50­1

00­5

00

5010

0

PP ­ Farbtest Total Error Score, binokular

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MethodsMethods:: ContrastContrast VisionVision

Pelli­Robson­Charts

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ResultsResults:: ContrastContrast VisionVision

Periode/Helligkeit

Kon

trast

empf

indl

ichk

eit b

inok

ular

 95%

CI

1/500 1/1500 1/2500 2/500 2/1500 2/2500

1.80

1.85

1.90

1.95

2.00

2.05

2.10

Helligkeitsdifferenzen

Kon

trast

empf

indl

ichk

eit b

inok

ular

 95%

CI

Diff 1500 Diff 2500 Diff 2500 / 15000.

000.

050.

100.

15

PP ­ Kontrastempfindlichkeit binokular

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MethodsMethods::ContentednessContentedness withwith illuminationillumination

Wie zufrieden sind Sie mit der Beleuchtung an Ihrem Arbeitsplatz heute?

sehr _______________________________ gar nicht

a1

EAGOSH, May 2007

B. Wilhelm

HowHow satisfiedsatisfied areare youyou withwith thisthis brightnessbrightnesslevellevel??

Periode/Helligkeit

Bel

euch

tung

 Arb

eits

plat

z, V

AS

 95%

CI

1/500 1/1500 1/2500 2/500 2/1500 2/2500

020

4060

80

Helligkeitsdifferenzen

Bel

euch

tung

 Arb

eits

plat

z, V

AS

 95%

CI

Diff 1500 Diff 2500 Diff 2500 / 1500

­50

050

100

PP ­ Beleuchtung Arbeitsplatz, VAS

EAGOSH, May 2007

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HowHow dodo youyou feelfeel todaytoday??

Periode/Helligkeit

Stim

mun

g, V

AS

 95%

CI

1/500 1/1500 1/2500 2/500 2/1500 2/2500

020

4060

8010

0

Helligkeitsdifferenzen

Stim

mun

g, V

AS

 95%

CI

Diff 1500 Diff 2500 Diff 2500 / 1500­6

0­4

0­2

00

2040

60

PP ­ Stimmung, VAS

EAGOSH, May 2007

B. Wilhelm

OverallOverall wellwell­­beingbeing inin thethe workplaceworkplace todaytoday??

Periode/Helligkeit

Gef

ühl A

rbei

tspl

atz,

 VA

S 9

5%C

I

1/500 1/1500 1/2500 2/500 2/1500 2/2500

020

4060

8010

0

Helligkeitsdifferenzen

Gef

ühl A

rbei

tspl

atz,

 VA

S 9

5%C

IDiff 1500 Diff 2500 Diff 2500 / 1500

­60

­40

­20

020

4060

80

PP ­ Gefühl Arbeitsplatz, VAS

EAGOSH, May 2007

B. Wilhelm

HowHow alert /alert / sleepysleepy dodo youyou feelfeel rightright nownow??

Periode/Helligkeit

Wac

hhei

t VA

S 95

%C

I

1/500 1/1500 1/2500 2/500 2/1500 2/2500

2040

6080

Helligkeitsdifferenzen

Wac

hhei

t VA

S 95

%C

I

Diff 1500 Diff 2500 Diff 2500 / 1500­6

0­4

0­2

00

2040

PP ­ Wachheit VAS

Diff 2500*

EAGOSH, May 2007

B. Wilhelm

MethodsMethods::PupillographicPupillographic SleepinessSleepiness TestTest

PST by AMTech, Weinheim

EAGOSH, May 2007

B. Wilhelm

PupillographicPupillographic SleepinessSleepiness TestTest

wide alert

very sleepy PUI17,4 mm/min

PUI4,3 mm/min

EAGOSH, May 2007

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DiscussionDiscussion

Reflexion:• sample size issues• optimal feasible design• reliability

– correlations– plausible values

Comparison:• laboratory experiments:

subjective scales­ same results

• night shift­ not directly comparable

• physiological studies(vision)­ same results

EAGOSH, May 2007

B. Wilhelm

ConclusionsConclusions

• no improvement by very brigth light in visualperformance, psychological measures or alertnesscompared to 500lx

• no reason to expect higher productivity / betterquality of work

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B. Wilhelm

•500lx recommendable and sufficient

•general recommendation of 2500lx not useful

•ecological and economical consequences enormous

ConclusionsConclusions

EAGOSH, May 2007

B. Wilhelm

Thanks for a splendid cooperation to:Rainer Röck, Dr. med. Carl Fahr, Alexander Baier and theentire staff at PWT/VBT

EAGOSH, May 2007

B. Wilhelm

EAGOSH, May 2007

B. Wilhelm

Der „Blendvisus“, B. Hauser, H. Ochsner,E. Zrenner, 1992

1001.000

10.000 cd/m²

Vision and Vision Perception, 1965

500 ­ 2500 lx80 ­ 400 cd/m²

0,27 2,7 27 270 2700cd/m²Testfeldleuchtdichte

Modifiziert nach König, 1934

EAGOSH, May 2007

B. Wilhelm

0.4

1.0

5°

SehschärfeSehschärfe

ZapfendichteZapfendichte

EmpfindlichkeitsbereichStäbchen: 1/100.000 cd/m² ­ 3 cd/m²Zapfen: 5/1000 cd/m² ­ ca. 10.000 cd/m²­> 9 Zehnerpotenzen

EAGOSH, May 2007

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ExzentrizitätR

ezep

tord

icht

e 10

.000

/mm

²

EAGOSH, May 2007

B. Wilhelm

Zwei Linien im Abstand einer Bogenminutekönnen aufgelöst werden

Sehschärfe = 100 % per Definition

1‘

Sehschärfe

Prüfung mit Standardsehzeichen, z.B. Landoltring