masashiro shibuya, junichi hirota, kimihiro yamanaka and mitsuyuki kawakami tokyo metropolitan...
TRANSCRIPT
Examination of the causes of visual ability lowering due to
aging
Masashiro SHIBUYA, Junichi HIROTA, Kimihiro YAMANAKA and Mitsuyuki KAWAKAMI
Tokyo Metropolitan University
1
Japan Now!
Age groups Both sexes Male Female 0~14 years old 1718 13.5 880 14.1 838 12.8
15~64 years old 8234 64.5 4142 66.5 4092 62.5
65 years and over 2819 22.1 1203 19.3 1616 24.7
70 years and over 2017 15.8 820 13.2 1197 18.3
75 years and over 1321 10.3 498 8.0 823 12.6
80 years and over 751 5.9 251 4.0 500 7.6
Total 12771 100.0 6225 100.0 6546 100.0
Population Estimates by Age Group and Sex
Percentage distributionPopulation (Ten thousand persons)Sept. 15,2008 (Provisional estimates)
2
Employee by age group and type of employment
Employee
Employee,
excluding
excecutive of company or
corporation
Regular staff
Non-regular
staff
Part-time
worker, Arbeit(tempo
rary worker
)
Part-time
worker
Arbeit (tempo
rary worker
)
Dispatched
worker from
temporary
labour agency
Contract
employee or entrust
ed emplo
yee
Other
Feb. 1988 4422 4132 3377 755 599 443 156 - 156 15 to 24 years old 620 617 512 106 96 17 79 - 10 25 to 34 years old 1005 983 878 105 84 59 25 - 21 35 to 44 years old 1220 1149 927 222 198 177 21 - 24 45 to 54 years old 977 889 717 172 143 130 13 - 29 55 to 64 years old 494 422 307 115 61 48 13 - 54 65 years old or more 106 71 36 34 16 11 5 - 18Feb. 1997 5349 4963 3812 1152 945 638 307 - 207 15 to 24 years old 728 725 491 234 220 28 192 - 14 25 to 34 years old 1249 1219 1049 169 132 89 43 - 37 35 to 44 years old 1119 1052 832 220 194 173 21 - 26 45 to 54 years old 1315 1195 929 266 235 213 22 - 31 55 to 64 years old 740 633 448 185 123 106 17 - 62 65 years old or more 199 139 63 76 41 29 12 - 352007 Yearly average 5561 5174 3441 1732 1164 822 342 133 298 137 15 to 24 years old 545 544 292 253 202 31 171 18 25 8 25 to 34 years old 1289 1265 940 326 181 116 64 52 67 26 35 to 44 years old 1288 1222 890 332 229 199 30 31 48 24 45 to 54 years old 1155 1068 740 327 240 218 22 15 45 27 55 to 64 years old 997 866 512 354 230 197 33 11 81 32 65 years old or more 287 209 68 140 83 61 22 5 32 20
(Ten thousand persons)
Government policy Employment Services for the Elderly
Subsidies for Promoting the Employment of the Elderly
Support for Employers involved in the Employment of the Elderly
Educational Activities Concerning Employment of the Elderly
Supporting the Vocational Goals of Middle-aged and Older Workers
4
aim
To make guidelines for job redesign by clarifying the cause of older people's visual ability lowering.
More than 80% of daily living information comes through the eyes
5
The condition of this experiment
1 2 3 4 5 6 7
Angle(o) 13.7o 11.7o 9.7o 7.7o 5.7o 3.7o 1.7o
Distance(cm)
13.08 15.39 18.63 23.53 31.81 48.81 105.05
21 kinds of combinations
the visual index presentation distance
1 2 3 4 5 6 7
Small 0.46 0.54 0.65 0.82 1.11 1.71 3.67
Medium 0.69 0.81 0.98 1.23 1.67 2.56 5.50
Large 0.91 1.07 1.30 1.64 2.22 3.41 7.34
the index size of the experiment conditions
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The procedure of the experiment
Accommodo PolyrecorderThe subjective symptoms index (SSI)
Watch the marker until a Landolt ring appeared
Shift visual lines to the ring
Tell aloud its break as soon as possible
Return his visual lines to the marker after the ring disappeared
Taking a picture of pupil
Accommodo PolyrecorderThe subjective symptoms index (SSI)
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The evaluation indexes(1) Reaction time
The time the subject took from the moment he saw the Landolt ring to the moment he told the break of the ring.
(2) The direction of the visual lines The reflection of the maker or the Landolt ring on the
subject’s eyes was used. The light from the marker or ring was reflected on the pupil. The positional relation between this reflection light(Purkinje-Sanson mirror image) and the pupil was used as a visual Line index.
(3) The degree of eye strain This was examined using the relative evaluation before
and after work of Near Point Distance, Contraction Time and Relaxation Time obtained from the Accommodo Polyrecorder, and Subjective Symptoms Index.
9
Result and discussion
(1) Reaction Time
Variables Observed variance of ratio p-value
individual differences(A) 89.869 4.07E-73 **
visual index sizes(B) 2.338 0.098093
visual index distances(C) 11.302 1.66E-11 **
factor(AB) 1.626 0.070586
factor(AC) 1.358 0.075913
factor(BC) 1.449 0.142286
factor(ABC) 0.928 0.653934
The results of the ANOVA (younger person)
**: p<0.01
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Result and discussion
(1) Reaction Time
The results of the ANOVA (older person)
**: p<0.01
Variables Observed variance of ratio p-value
individual differences(A) 70.640 9.36E-38 **
visual index sizes(B) 44.785 6.5E-17 **
visual index distances(C) 34.510 8.03E-29 **
factor(AB) 1.348 0.221566
factor(AC) 2.117 0.002662 **
factor(BC) 5.827 1.09E-08 **
factor(ABC) 2.333 2.11E-05 **
Average reaction time by size S
young old0.000
0.500
1.000
1.500
SML
rea
cti
on
tim
e(s
ec)
**
**
**: p<0.01
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Multiple comparison by visual line shift distance
distance 1 2 3 4 5 6 7 distance 1 2 3 4 5 6 71 ** ** ** ** ** 1 ** ** ** ** **2 * * * ** 2 * ** ** ** **3 3 * *4 45 56 67 7
Young person old person
*: p<0.05,**: p<0.01
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Reaction time in Size S
1 2 3 4 5 6 70
0.5
1
1.5
youngold
visual line shift distance
reac
tion
tim
e(se
c)
14
(2) The visual lines
1 2 3 4 5 6 7-10.00
-5.00
0.00
5.00
10.00
young(right eye)young(left eye)old(right eye)old(left eye)
Visual line distance (o)
Vis
ual l
ine
slip
page
(pix
)
The regression lines of visual lines
15
summary The insufficient eye ball adduction of
older persons causes more significant distance influence on reaction time in Size S compared with younger persons.
Specially in the distances of 11.7 o and 13.7o, information fusion from the right and the left eyes is much more difficult, which is thought to make great difference in reaction time.
16
(3) The degree of eye strain
Near Point Distance Contraction Time Relaxation Time0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
Young peopleOld people
Th
e r
ela
tive
va
lue
s o
f e
fore
an
d a
fte
r w
ork
(%)
17
The items of the subjective symptoms index
Category ⅠFeelings of drowsiness
Category ⅡFeelings of uneasiness
Category ⅢFeelings of discomfort
Category ⅣFeelings of
languor
Category ⅤFuzzy feelings
Feel drowsy Feel uneasy Have a headache
My arms feel heavy
Have blear eyes
Want to lie down Feel depressed Feel heavy in the head
My lower back feels heavy
Have eyestrain
Yawn Feel nervous Feel sick My hands or fingers ache
Have sore eyes
Can't motivate myself
Feel irritated Feel my brains muddled
My legs feel feel heavy
My eyes are blurred
Feel tired all over
Can't think clearly
Feel dizzy Have stiff shoulders
Japan Society for Occupation Health
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The avarage value of the fifth category before and after work
before work after work0.000
0.500
1.000
1.500
2.000
2.500
Young personOld person
sco
re o
f ca
teg
ory
V
19