Empirical Research on the Prevention of
Health-related Accidents and Research on
the Public Awareness Activities forPreventive Measures

Project Members
Project Leader
Takeshi Tanigawa (Professor, Course of Public Health, Juntendo University
Graduate School of Medicine)
Project Members<IATSS Members>
Takashi Oguchi（Professor, Institute of Industrial Science, The University ofTokyo）
Kazuhiro Ota （Professor, Senshu University School of Commerce）
Kazuko Okamura（Director, Second Traffice Science Section, Department ofTraffice Science, National Research Institute of Police Science）
Motoki Shino （Associate Professor, Graduate School of Frontier Sciences, The
University of Tokyo）
Masaya Takahashi (Director, Research Center for Overwork-Related Disorders,National Institute of Occupational Safety and Health, Japan)<Special Researchers>
Migiwa Asano（Professor, Department of Legal Medicine, Ehime University Schoolof Medicine）
Manami Kimura（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Shiho Kunmatsu（Vice President, Inoue Eye Hospital）
Setsuko Sato（Assistant Professor, Course of Public Health, Juntendo University
Graduate School of Medicine）
朱 沁曄（Master's Course, Course of Public Health, Juntendo University Graduate
School of Medicine）
Ryutaro Shirahama（Part-time Lecturer, Course of Public Health, Juntendo
University Graduate School of Medicine）
Shintaro Chiba（Professor, Department of Otorhinolaryngology, Jikei University
School of Medicine）
Kiyohide Tomooka（Assistant Professor,Course of Public Health, Juntendo
University Graduate School of Medicine）
Koutatsu Maruyama（Associate Professor, Ehime University Graduate School of
Agriculture）
Noriko Miyoshi（Representative Director, Ehime Sangyohoken Service）
i

Ayumu Murakami（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Hiroo Wada（Associate Professor, Course of Public Health, Juntendo University
Graduate School of Medicine）＜Research Collaborators＞
Yuya Imai（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Keisuke Onuki（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Noriko Sakiyama（Assistant Professor, Tokyo Healthcare University Faculty of
Nursing）
Yohei Suzuki（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Eisuke Takeyama（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Tomokazu Tajima（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）
Keiko Tanaka（Master's Course, Course of Public Health, Juntendo

University Graduate School of Medicine）
趙 暁旭（Master's Course, Course of Public Health, Juntendo University Graduate
School of Medicine）
Kentaro Yamato（Doctor's Course, Course of Public Health, Juntendo University
Graduate School of Medicine）＜Observers＞
Kotaro Aoki（Section Head of Training, License Division, Traffic Bureau,
National Police Agency）
Shohei Kanesaki（Section Head of Planning & Research, Traffic Planning
Division, Traffic Bureau, National Police Agency）
Kazuhisa Kawamura（The First Section Head of Safety Administration, Safety
Policy Division, Road Transport Bureau, Ministry of Land, Infrastructure,
Transport and Tourism）
Kazuaki Sumi

（Section Head of Training, License Division, Traffic

Bureau, National Police Agency）
Shoji Sekimoto（Section Head of Planning & Research, Traffic Planningii

Division, Traffic Bureau, National Police Agency）（Section Head of Laws & Regulations, Traffic Planning

Koji Takeuchi

Division, Traffic Bureau, National Police Agency）
Shinya Fujimoto（Assistant Director, Traffic Planning Division, Traffic Bureau,
National Police Agency）
Yu Hoshino（Section Head of Planning & Research, Traffic Planning

Division, Traffic Bureau, National Police Agency）
Tatsuya Horii（Assistant Director, License Division, Traffic Bureau,

National Police Agency）
Dai Yamazaki（Assistant Director of Safety Administration, Safety Policy

Division, Road Transport Bureau, Ministry of Land, Infrastructure, Transport
and Tourism）< Secretariat>
Saburo Ishihara（Senior Administrator, Operation Department, International
Association of Traffic and Safety Sciences）
Hiroyuki Kaneko（Managing Director and Secretary General, International
Association of Traffic and Safety Sciences）
Satoshi Kamata（Executive Director, International Association of Traffic and
Safety Sciences）
Harumi Hiroya（Chief Administrator, Operation Department, International
Association of Traffic and Safety Sciences）
Kozo Miyanari（Chief Administrator, International Association of Traffic and
Safety Sciences）
Toru Yoshihara（Department Manager of Operation, International Association of
Traffic and Safety Sciences）* The indicated positions are at the time of participation in the project.

iii

Table of Contents
Ⅰ．Background of the Study Project ........................................................ 1
1．Background and purpose of this study project - Why are health-related
accidents focused now?- ................................................................................ 1
2．Sleep Apnea Syndrome and Traffic Accidents............................................. 3
3．Abnormal Visual Field and Traffic Accidents ............................................. 6
4．Hay Fever-induced Sleepiness and Traffic Accidents .................................. 9
5．Project Outline ...................................................................................... 10

Ⅱ．《Research for FY2017》 Development of a questionnaire andestablishment and validation of a survey method using a clock chart....................................................................................................... 11

1．Background and Objectives .................................................................... 11
2．Method .................................................................................................. 12
2-1．Target ............................................................................................. 12
2-2．Questionnaire .................................................................................. 12
2-3．Clock Chart ..................................................................................... 13
3．Results .................................................................................................. 15
4．Conclusion ............................................................................................. 30

Ⅲ．《Research for FY2018》 Conducting Epidemiological ResearchStudies on Occupational Drivers ..................................................... 32

1．Background and Objectives .................................................................... 32
2．Method .................................................................................................. 32
2-1．Target ............................................................................................. 32
2-2．Questionnaire .................................................................................. 32
2-3．Clock Chart ..................................................................................... 33
2-4．Statistical Analysis ........................................................................... 33
3．Results .................................................................................................. 35
3-1．Characteristics of Target .................................................................. 35
3-2．Relationship between Daytime Sleepiness and Traffic Accidents ......... 36
3-3．Relationshipbetween

Knowledge

of

Hay

Fever

Medication

andMedication Behavior ................................................................................ 37
3-4．Relationship between Abnormal Visual Fields and Traffic Accidents ... 39
4．Conclusion ............................................................................................. 44
4-1．Relationship between Daytime Sleepiness and Traffic Accidents ......... 44iv

4-2．Relationshipbetween

Knowledge

of

Hay

Fever

Medication

andMedication Taking Behavior ..................................................................... 44
4-3．Relationship between Abnormal Visual Fields and Traffic Accidents ... 45

Ⅳ．《Research for FY2019》 Conducting Follow-up surveys for those with
Findings on Clock Chart ................................................................. 47

1．Background and Objectives .................................................................... 47
2．Method .................................................................................................. 47
3．Results .................................................................................................. 48
4．Conclusion ............................................................................................. 49

Ⅴ．《Implementation in FY2019》 Raising Awareness of the Prevention of
Health-related Accidents by Holding Symposiums and Lectures ..... 50

1．Holding Symposiums .............................................................................. 50
1-1.

Traffic Safety Symposium ................................................................ 50

1-2.

Special Lecture ............................................................................... 53

2．Results of Promotion Activities-Results of the Symposium Questionnaire- . 54
2-1.

Traffic Safety Symposium ................................................................ 54

2-2.

Special Lecture ............................................................................... 59

3．Conclusion ............................................................................................. 61

Ⅵ．Conclusion and Issues .................................................................... 62

1．Summary of this Study ........................................................................... 62

2．Aiming to reduce health-related accidents ............................................... 63

References ............................................................................................. 65
Appendix 1 Questionnaire .................................................................... 69
Appendix 2 Clock Chart Implementation Manual ................................. 73
Appendix 3 Clock Chart Result Sheet (Front) ....................................... 78
Appendix 4 Medical Checkup Status Survey Form ................................ 80
Appendix 5 Reminder to Those with Severe Findings ............................ 81
Appendix 6 Flyer for the Citizen's Symposium on Traffic Safety ........... 81
Appendix 7 Flyer on Special Lecture ..................................................... 83v

Ⅰ．Background of the Study Project
1．Background and purpose of this study project - Why are healthrelated accidents focused now?In Article 2 of the Automobile Accident Reporting Regulations of the Ministry ofLand, Infrastructure, Transport, and Tourism, health-related accidents are defined as“those in which the driver is unable to continue driving a commercial vehicle due toillness. 1 ) In recent years, the number of traffic accidents, injuries, and fatalities has
been on a downward trend in Japan. However, on the other hand, the number ofreported health-related accidents has been on an upward trend (Fig. 1). 2 ) One possible
reason for this is that the number of reports is increasing, reflecting the growing
awareness of business operators of health-related accidents, etc. However, anotherpossible reason is that, as the entire Japanese society is aging, many occupational
drivers are also aging. The percentage of those with lifestyle-related diseases, etc.,that pose a risk of health-related accidents is increasing.
According to the Ministry of Land, Infrastructure, Transport and Tourism
announcement, cerebrovascular disease and heart disease accounted for 16% and 14%,respectively, of the drivers who caused health-related accidents between 2012 and2016. Of these, the breakdown by disease of the drivers who died is reported to be
50% for heart disease and 15% for brain disease 2 ) . Under these circumstances, theMinistry of Land, Infrastructure, Transport, and Tourism has begun to take measures toprevent and reduce health-related accidents, including the creation of the “Guidelines
for Measures against Cerebrovascular Disease in the Automobile Transport Industry”
in 2008. 3 )1

Figure 1: Number of Reports of Health-related Accidents(Number of Cases per Business Category)
However, in addition to cerebrovascular diseases and heart diseases, various otherdiseases such as digestive diseases, respiratory diseases, and side effects ofmedications have been reported to cause health-related accidents. 2 ) Furthermore,
previous reports on the causes of health-related accidents did not include healthrelated accidents caused by drivers who were unaware of their diseases. In otherwords, cerebrovascular disease and heart disease are just the tip of the iceberg
regarding the causes of health-related accidents (Fig. 2). With the aging ofoccupational drivers, it is possible that various lifestyle-related diseases could be thecause of health-related accidents. Comprehensive measures to deal with health-related
accidents, including diseases the driver is unaware of, will be necessary.
In this project, we focused on the following causes of health-related accidents: lossof concentration during the day due to sleep disordered breathing, abnormal visual
fields due to glaucoma, and drowsiness due to hay fever. This project aimed to clarify
the relationship between these health problems and traffic accidents and establish andpromote awareness of countermeasures against health-related accidents.

2

Figure 2: Causes of Health-related Accidents

2．Sleep Apnea Syndrome and Traffic Accidents
Sleep apnea syndrome (SAS) is a syndrome associated with sleep disorderedbreathing (SDB), an abnormal condition related to breathing during sleep, such as
respiratory arrest and hypoventilation, and subjective symptoms such as daytime
sleepiness, poor concentration, and fatigue. The number of SAS patients in Japan isestimated to be 4 to 5 million. In contrast, the number of patients currently undergoingtreatment is only about 400,000, equivalent to about one-tenth of the total number of
SAS patients. This is because 1) symptoms of SAS gradually become more severe andthe decline in sleep quality follows a chronic course, so sleepiness caused by SAS is
easily misinterpreted as age-related chronic fatigue symptoms, 2) potential SAS
patients are often unaware of excessive daytime sleepiness, and 3) the spread ofscreening tests for SAS and linkage to treatment are insufficient. 4 )In recent years, it has become clear that SAS has an impact on patients’ health, suchas cardiovascular diseases including diabetes, hypertension, and cerebrovasculardiseases, and has a significant social impact, including traffic accidents, because it
causes drowsiness during the day. 5 ) According to the results of a meta-analysis
conducted by Sassani et al. on the association between SDB and road traffic accidents,
the risk of road traffic accidents was reported to be about 2.5 times higher in drivers
with SDB (Fig. 3). 6 )In addition, according to a study on therapeutic intervention for3

SAS using continuous positive airway pressure (CPAP), it was found that therapeuticintervention can reduce the number of traffic accidents. 7 ) An estimate in the U.S.
suggests that the cost of CPAP intervention is greater than the economic loss fromtraffic accidents and could save 980 lives. 6 ) This suggests that therapeutic intervention

for sleep apnea in occupational drivers is significant.
Figure 3: Increased Risk of Traffic Accidents Due To Obstructive Sleep Apnea
Syndrome

While the impact of SAS-induced drowsiness while driving on traffic accidents has
been clarified, we conducted a questionnaire survey on traffic accidents and nearmisses among SAS patients. We found that there were many cases of falling asleep at
the wheel without warning, such as “I fell asleep at the wheel 12 times in one year,
and when I noticed, I collided with the car in front of me that was stopped at a red
light. 8 )In fact, a simple SAS screening test using the flow sensor method and aquestionnaire to determine subjective daytime sleepiness (ESS; Epworth sleepinessscale) were conducted simultaneously on approximately 5,000 truck drivers
nationwide. As a result, as many as 86% of the patients with moderate to severe SDB
were judged to have subjective sleepiness in the normal range, as shown in Table 1. 9 )Based on these results, we have proposed the concept of sleep apnea without
subjective daytime sleepiness (NoSSA; non-sleepy sleep apnea) and have called forattention to it. 4 )4Sleep Apnea

Weak↑
Perceived
Sleepiness↓
StrongESS
0 to 5ESS
6 to 10ESS
11 to 15ESS
16 to 20
Total

NormalRange(Less than
RDI 5)

1,457
(60%)
774
(32%)
142
(6%)
37
(2%)
2,410
(100%)

SlightDegree(RDI 5 to
19.9)

1,391
(60%)
725
(31%)
170
(7%)
44
(2%)
2,330
(100%)

MediumDegree(RDI 20 to
39.9)

201
(53%)
138
(37%)
34
(9%)
5
(1%)
378
(100%)

Severe(RDI 40 or
more)

Total

46
(36%)
52
(40%)
23
(18%)
8
(6%)
129
(100%)

3,095(100%)
1,689(100%)
369(100%)
94(100%)
5,247(100%)

Table 1: Relationship between Perceived Sleepiness and Prevalence of Sleep Apnea
SyndromeThus, since SAS is upstream of various lifestyle-related diseases, and falling asleep
due to SAS may directly lead to serious accidents, it is considered that SAS medical
checkups for the entire society, especially for people engaged in driving, are importantin preventing health-related accidents. In addition, since SAS, like NoSSA, is adisease that lacks subjective findings, it is considered necessary to introduce a simple
objective test for primary screening.

5

3．Abnormal Visual Field and Traffic Accidents
The visual field is the size of the field of vision that can be seen when gazing at asingle point in front of the eyes. A partial loss or narrowing of this field of vision iscalled an abnormal visual field. In Japan, glaucoma is the most common cause ofvisual field abnormalities at 28.6%, followed by retinitis pigmentosa at 14.0% anddiabetic retinopathy at 12.8%. 1 0 ) Of these, the number of glaucoma patients in Japanwas estimated to be approximately 4.6 million in 2015, and 5.0% (1 in 20) of people
who are 40 years or older and 10.0% (1 in 10) of people who are 70 years or older are
considered to have glaucoma. 11 ) Glaucoma is also the most frequently occurring
disease, accounting for about 30% of all cases of blindness in Japan. Glaucoma is adisease in which the optic nerve is damaged for some reason, resulting in a narrowingof the visual field, and increased intraocular pressure is thought to be one of thecauses. Once glaucoma has progressed, it is difficult to recover from it, but intraocularpressure lowering therapy can reduce its progression, so early detection and treatment
are essential. Another characteristic of glaucoma is that its symptoms progress
gradually, making it difficult to notice on one’s own, and there are no subjective
symptoms until the condition is quite advanced. Another reason for the lack ofsubjective symptoms is that glaucoma begins with narrowing of the peripheral visual
field. The central visual field is maintained even after the symptoms have progressedconsiderably. Glaucoma often progresses in one eye at a time so that the defective
portion of the visual field is compensated for when viewed with both eyes (Fig. 4).

6

Sin ce there are no symptom s, the person will
not be aware o f it, an d if the v isual fielddiso rder progresses…

Left

Right

Field of view with superimposed
visual field charts for both eyes

Figure 4: Visual Field Progression in Glaucoma Patients

It has been reported that about 90% of glaucoma patients have no subjective symptoms
and remain untreated, regardless of the degree of symptoms (Table 2). 1 2 ) In addition,
most cases of glaucoma are discovered by chance during a complete medical checkup
or eye examination when purchasing eyeglasses or contact lenses. It is reported that
only 5% of glaucoma patients have subjective symptoms.

7

Table 2: Ratio of Glaucoma Unawareness and Untreated Patients by Stage
among 250 Glaucoma Patients

Regarding the impact of abnormal visual fields caused by glaucoma on driving, it
has been found that glaucoma patients experience what is commonly called the “Jackin-the-Box Phenomenon” while driving, such as “a car, bicycle, or pedestrian suddenly
has jumped out in front of me (or has disappeared from in front of me)”, “a stop signthat should normally be there has been missing,” and “a traffic light that should bethere at an intersection has been missing. 1 3 )It has been clearly shown that such

reduced visibility while driving due to abnormal ふ fields of vision can cause traffic
accidents.

Previous studies showed that abnormal peripheral vision in both eyes

doubled the rate of car accidents, 1 4 ) that the incidence of glaucoma in elderly people
who caused car accidents was 3.6 times higher than in elderly people who did notcause car accidents, 1 5 ) and that glaucoma patients had a 6.6 times higher risk of
causing a car accident in the past five years than normal people. 1 6 ) . In Japan, as aresult of a study by Aoki et al. on the relationship between the progression ofglaucoma and a history of traffic accidents in the past five years in 29 glaucoma
patients, they reported that the percentage of those with a history of traffic accidents
was 6.9% and 0% in the early and middle glaucoma groups, respectively, while it wassignificantly higher at 34.5% in the late group. 1 7 )On the other hand, it has also been reported that glaucoma patients tend to avoid
driving at night, in fog, or in the rain, which makes them more cautious drivers andless likely to cause accidents. 1 8 ) Furthermore, it is suggested that glaucoma has
specific characteristics for traffic accidents depending on the location of the abnormal
8visual field. 1 9 ) In other words, early detection and early treatment of glaucoma is
important to prevent the progression of the disease and prevent traffic accidents bymaking glaucoma patients aware of their symptoms.
In Japan, however, few systematic measures have been taken to prevent healthrelated accidents due to abnormal visual fields caused by glaucoma. In our aging
society, the number of symptomless glaucoma patients is likely to increase further inthe future. In particular, since traffic accidents by occupational drivers have asignificant social impact, the development and expansion of a screening system for
occupational drivers for early detection and early treatment of abnormal fields ofvision are considered to be essential issues in preventing traffic accidents.

4．Hay Fever-induced Sleepiness and Traffic Accidents
In recent years, the number of hay fever patients has been increasing, and theprevalence in Japan has been reported to have reached more than 25%. 2 0 ) The
prevalence of cedar pollen allergy, in particular, is reported to be more than 30%
among people in their teens to 50s, and the prevalence is high among the working-age
population. 2 1 ) Hay fever induces sleepiness during the daytime because the main
symptoms, such as nasal obstruction, runny nose, sneezing, and itchy eyes, reduce
sleep quality. 2 0 ) On the other hand, second-generation antihistamines, which are themainstay of drug therapy, can induce daytime sleepiness when taken. 2 2 ) According toan Internet survey of about 1,200 hay fever patients conducted in Japan, about 80% of
hay fever patients complained of sleep disturbance due to their symptoms, and about
60% of patients felt more sleepy during the daytime during the pollen dispersal season
than during the pollen non-dispersal season. 2 3 ) About 40% of the respondents said thatthe cause of this was sleepiness caused by therapeutic medication, but more than 50%
said that the cause of this was sleepiness caused by disturbed sleep at night due to hay
fever symptoms or conditions. 2 3 ) In the cedar pollen dispersal season, more than 90%
of patients reported that their work/study was affected by hay fever symptoms. In
comparison, about 80% of hay fever medication patients reported that the treatment
improved their work/study efficiency. About 80% reported that they did not feel
sleepiness that affected their work/study due to hay fever medication (Table 3). 2 3 )Since some second-generation antihistamines are non-sedating agents with less central
nervous system depressant effects, 24 ) appropriate medication behavior is expected to
improve QOL (quality of life) during the day. However, it has been reported that about
one in four hay fever patients did not visit a medical institution even though they had
9the intention to do so, and that about half of those who did not visit a medical
institution ended up purchasing OTC drugs at a pharmacy. 2 3 ) 花 There are two types of
hay fever medicines: prescription medicines prescribed by medical institutions andover-the-counter medicines available at pharmacies. Since patients can take these
medicines according to their drug selection, their knowledge of the medicines, drug
selection, and medication-taking behavior may affect their daytime activities such as
driving. In the “Survey on Drivers and ‘Hay Fever’ (2007)” conducted by the Forumfor the Promotion of Healthy Japan 21, about 30% of the respondents answered that“hay fever symptoms greatly or considerably affect driving a car “. 2 2 ) As fortherapeutic medication, there are some second-generation antihistamines indicated intheir package inserts with cautions or prohibitions for driving, etc., and it has beenreported that these drugs are prescribed to about 70% of hay fever patients. 2 5 ) In
recent years, in addition to sleepiness and fatigue that are perceived as side effects ofantihistamines, unperceived “impaired performance” (a decrease in concentration,
judgment, and work efficiency that the patient him/herself is not even aware of) has
become a problem. 2 5 ) From the viewpoint of preventing automobile accidents, drivers
need to know how to alleviate hay fever symptoms and have knowledge about
medicines, selection of therapeutic drugs, and medication-taking behavior.
Thus, not only do hay fever symptoms cause a decrease in driving performance, but
the antihistamines used to treat hay fever may also lead to a decrease in consciousness
level and concentration due to sleepiness, a decrease in cognitive and operational
abilities, and poor driving maneuvers. 2 6 ) Therefore, hay fever is considered a potential
cause of health-related accidents.

In particular, since occupational drivers spend

many hours driving, symptoms of hay fever and sleepiness caused by medication may
affect their driving operation and cause traffic accidents due to these symptoms.
Therefore, Awareness-raising on appropriate medication use is considered to benecessary.

5．Project Outline
This research project was carried out as a three-year project from FY 2017 to FY 2019.
The outline of each year’s research is shown below. (Fig. 5)
Fiscal Year 2017
-Development of a questionnaire and establishment and validation of a survey method
using a clock chart
Fiscal year 201810

-Implementation and analysis of a survey on health-related accidents targeting
approximately 2,000 employees of transportation companies
FY2019-Conduct follow-up surveys of employees with findings on clock charts-Raise awareness of the prevention of health-related accidents by holding symposiums
and lectures
The details of each year’s implementation will be described in Chapters II-V.
2017

Development of aquestionnaire andestablishment andvalidation of a survey
method using a clock
chart

2019

2018



Implementation andanalysis of a survey
on health-related
accidents targeting
approximately 2,000
employees oftransportationcompaniesConduct follow-up surveys
of employees withfindings on clock charts
Raise awareness of theprevention of healthrelated accidents byholding symposiums andlectures

Figure 5: The Research Project Outline

Ⅱ．《Research for FY2017》
Development of a questionnaire and establishment
and validation of a survey method using a clockchart
1．Background and Objectives
In FY 2019, we first developed a questionnaire to conduct a survey and study toclarify the relationship between sleep apnea, glaucoma, and sleepiness caused by hay
fever and traffic accidents. We used the clock chart to examine the survey method, asimple screening tool for abnormal visual fields. Then, we aimed to verify theusefulness of these research methods by conducting a pilot study on actual glaucoma
patients.

11

2．Method
2-1．Target
In this study, subjects were six outpatients (3 males and three females) who visitedthe Department of Ophthalmology at Juntendo University Hospital and nineoutpatients (four males and five females) who visited Tetsumoto Eye Clinic between
February and March 2018. Of these, this report describes 14
patients with the Humphrey automated visual field test (Figure6). This study was conducted with the approval of the Juntendo
University Hospital Ethics Committee ( Acceptance Number: 17270) and the Juntendo University School of Medicine Ethics
Committee (Approval Number: Jun Dai I Rin No. 2017204).

Figure 6:

Humphrey Automated Field

2-2．Questionnaire
Regarding driving a car or motorcycle, respondents were asked, “Do you currently
drive a car or motorcycle?” Respondents answered “yes” or “no” to the question, andif they answered “yes,” they were asked, “Have you ever had any of the following
experiences while driving a car or motorcycle within the past five years?” Nine items
related to the jack-in-the-box phenomenon were asked (all questions were answeredwith two choices, “yes” or “no”) (Table 3). In addition, respondents were asked “Haveyou ever caused a traffic accident in the past five years?” Respondents answered “yes”
or “no.” If the answer is “Yes,” the respondents were asked to indicate the number oftimes they had been involved in the following situations: “You damaged your own
vehicle. (single car accident),” “You were hit by another car or motorcycle. (property
damage)”, “You hit another car or motorcycle. (property damage),” “The other party’s
negligence resulted in personal injury.”, “Both the other party and your negligence
resulted in personal injury,” and “Your negligence resulted in personal injury.”
While driving a car or motorcycle, have you had any of the following experiences in
the past five years?
There were times when traffic lights that were supposed to be at

Yes

No

Yes

No

intersections were missing.
There were times when the stop signs that should usually be there
12were missing.
There were times when a car or bicycle suddenly jumped out in front

Yes

No

of you or disappeared right in front of you.
There were times when a pedestrian suddenly jumped out in front of

Yes Noyou or disappeared right in front of you.
You may find yourself slowing down or speeding up before you

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

know it compared to the flow of cars in the vicinity.
Sometimes you think you are driving in the proper lane, but before
you know it, you end up driving onto the sidewalk or into theoncoming lane.
Sometimes it is difficult to see road signs clearly and to drive
according to the signs.
Sometimes you get confused because you don’t know where you are
driving on the road.
You have been pointed out by a passenger, such as a family member,that you were driving dangerously.
Table 3: Questions and Answers on Jack-in-the-box Phenomenon

2-3．Clock Chart
In this study, we used the clock chart, a simple screening tool for abnormal visual
fields developed by Professor Chota Matsumoto of Kinki University, which is
performed with one eye. 2 7 ) The clock chart is made of a circular piece of paper with adiameter of 40 cm. A grid and petals are drawn within a viewing angle of 5° from thecenter, a ladybug at 10°, a caterpillar at 15°, a butterfly at 20°, and a cat at 25° (Fig.
7). Although the clock chart was created for self-checking, in this study, to improve
the accuracy of the test, the clock chart was placed on a base with a large clock faceon it, and the test was conducted under the guidance of an examiner (Fig. 8). First,
with the subject gazing at the center of the clock chart with one eye from a distance ofabout 35 cm, it was confirmed that a caterpillar located in the Marriott blind spot
would not be visible. In this state, the clock chart was rotated slowly in a clockwise
direction, stopped every 30°, and the visibility of the illustration of the creature wasrecorded. In this study, we tested the following viewing angles in order: ladybug (10°),
caterpillar (15°), butterfly (20°), and cat (25°). In addition, we confirmed the Marriott
blind spot for each viewing angle tested and confirmed the solid viewpoint for each90° rotation.
13

Figure 7: Clock Chart

Figure 8: Clock Chart Inspection Scene

14

3．Results
The following is a comparison of the results of the clock chart and the results of the
Humphrey automated visual field test for the 14 cases in this study, as well as a
description of the driving conditions, the presence or absence of the Jack-in-the-box
phenomenon, and the experience of traffic accidents.
Case (1)■48-year-old male■Non-motor-vehicle operator
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 0/16
False Positive: 0%
False Negative: 0%

15

Poor Fixation: 0/14
False Positive: 0%
False Negative: 0%Case (2)■68-year-old female■Non-motor-vehicle operator
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 13/17
False Positive: 1%
False Negative: 10%

Figure 10: Results of Clock Chart and Humphrey AutomatedVisual Field Test for Case 2

16

Poor Fixation: 5/18
False Positive: 1%
False Negative: 13%

Case (3)■82-year-old male (The right eye has almost lost its field of vision, so only 10° fromthe center is shown in the test results.)■Non-motor-vehicle operator
Clock Chart Result
Right Eye

Left Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 3/17
False Positive: 2%
False Negative: 6%

Poor Fixation: 0/17
False Positive: 2%
False Negative: N/A

Figure 11: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 317

Case (4)■74-year-old female■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: None
■Traffic accident experience in the past five years: None
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 1/13
False Positive: 6%
False Negative: 0%

Poor Fixation: 0/13
False Positive: 0%
False Negative: 0%

Figure 12: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 418

Case 5■ 63-year-old male■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: None
■ Traffic accident experience in the past five years: None
Clock Chart Result
Right Eye

Left Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 1/14
False Positive: 3%
False Negative: 7%

Poor Fixation: 1/17
False Positive: 1%
False Negative: 0%

Figure 13: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 519

Case 6■70-year-old female■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・You may find yourself slowing down or speeding up before you know it
compared to the flow of cars in the vicinity.
■ Traffic accident experience in the past five years: None
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 5/12
False Positive: 3%
False Negative: 18%

Poor Fixation: 4/11
False Positive: 40%
False Negative: 32%

Figure 14: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 620

Case 7■72-year-old female■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・You may find yourself slowing down or speeding up before you know it
compared to the flow of cars in the vicinity.
■Traffic accident experience in the past five years: Yes
・Property damage (hit by another car or motorcycle) 10 times
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 0/11
False Positive: 6%
False Negative: 12%

Poor Fixation: 1/12
False Positive: 14%
False Negative: 18%

Figure 15: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 721

Case 8■74-year-old male■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: None
■Traffic accident experience in the past five years: Yes
・Property damage (hit by another car or motorcycle) 2 times
Clock
ClockChart
ChartResult
ResultRight Eye

Left Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 0/10
False Positive: 9%
False Negative: 0%

Poor Fixation: 0/11
False Positive: 2%
False Negative: 0%

Figure 16: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 822

Case 9■78-year-old male■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・There were times when the stop signs that should usually be there were missing.
・There were times when a car or bicycle suddenly jumped out in front of you ordisappeared right in front of you.
■Traffic accident experience in the past five years: Yes
・Property damage (hit by another car or motorcycle) 3 times
・Another driver’s negligence resulted in personal injury.

2 times

Clock
Clock
Clock
Clock
Chart
Chart
Chart
Chart
ResultResultResultResultLeft Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 2/10
False Positive: 2%
False Negative: 6%

Poor Fixation: 2/11
False Positive: 12%
False Negative: 10%

Figure 17: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 923

Case 10■78-year-old male(The left eye has lost its field of vision, so the clock chart test was
not conducted.)■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・There were times when a car or bicycle suddenly jumped out in front of you ordisappeared right in front of you.
・There were times when a pedestrian suddenly jumped out in front of you ordisappeared right in front of you.
・You may find yourself slowing down or speeding up before you know it
compared to the flow of cars in the vicinity.
・You have been pointed out by a passenger, such as a family member, that you
were driving dangerously.
■Traffic accident experience in the past five years: None24

Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 0/13
False Positive: 0%
False Negative: N/A

Poor Fixation: 7/12
False Positive: 11%
False Negative: 9%

Figure 18: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 1025

Case 11■52-year-old male■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: None
■Traffic accident experience in the past five years: None
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey
HumphreyAutomatedAutomatedVisual
VisualField
FieldTest
TestResult
ResultPoor Fixation: 3/11
False Positive: 4%
False Negative: 0%

Poor Fixation: 0/11
False Positive: 4%
False Negative: 0%

Figure 19: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 1126

Case 12■71-year-old female■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: None
■ Traffic accident experience in the past five years: None
Clock Chart Result
Right Eye

Left Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 0/12
False Positive: 2%
False Negative: 0%

Poor Fixation: 2/13
False Positive: 5%
False Negative: 0%

Figure 20: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 1227

Case 13■78-year-old male■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・You may find yourself slowing down or speeding up before you know it
compared to the flow of cars in the vicinity.
■ Traffic accident experience in the past five years: None
Clock Chart Result
Left Eye

Right Eye

Blind

Blind

S po tS po tHumphrey
HumphreyAutomatedAutomatedVisual
VisualField
FieldTest
TestResult
ResultPoor Fixation: 2/12
False Positive: 1%
False Negative: 9%

Poor Fixation: 0/12
False Positive: 19%
False Negative: 6%

Figure 21: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 1328

Case 14■68-year-old female■Motor-vehicle operator■Jack-in-the-box Phenomenon in the past five years: Yes
・Sometimes you get confused because you don’t know where you are driving on
the road.
■Traffic accident experience in the past five years: Yes
・Property damage (hit by another car or motorcycle) 2 times
Clock Chart Result
Right Eye

Left Eye

Blind

Blind

S po tS po tHumphrey Automated Visual Field Test Result

Poor Fixation: 6/11
False Positive: 1%
False Negative: 0%

Poor Fixation: 0/10
False Positive: 0%
False Negative: 0%

Figure 22: Results of Clock Chart and Humphrey Automated Visual Field Test for
Case 1429

4．Conclusion
This study conducted clock chart tests on 14 glaucoma patients and compared theresults with those of the Humphrey automated visual field test. In almost all cases, theabnormalities found in the visual field by the clock chart and those by the Humphrey
automated visual field test were generally consistent. In a previous study thatvalidated the validity of the clock chart, the concordance rate when classified by the
Allhom classification modified Greve method was 85% for stages 0 to 1 and 100% forstages 2 to 4, reporting high validity. 2 7 ) Of the 11 patients in this study who answeredthat they drove a car or motorcycle, 6 had experienced the Jack-in-the-box
Phenomenon in the past 5 years. Specifically, one respondent answered, “There was atime when a stop sign that should normally be there was missing. 2 respondents
answered, “Suddenly, a car or bicycle jumped out in front of me, or disappeared fromin front of me,” 1 respondent answered, “Suddenly, a pedestrian jumped out in front ofme, or disappeared from in front of me,” and 1 respondent answered, “Sometimes, thespeed of my car slows down or becomes faster than the flow of cars around me.” One
respondent said, “Sometimes I feel confused because I don’t know where on the road I
am driving.” One respondent answered, “A family member or other passenger has
pointed out to me that I was driving dangerously.”
Similarly, of the 11 patients who answered that they drove a car or motorcycle, 4 had
experienced a traffic accident within the past 5 years. The patients with traffic
accident experience had repeated accidents two or more times. Three out of four
patients with traffic accident experience had experienced the Jack-in-the-box
Phenomenon. These results suggest that the combination of screening for abnormal
visual fields using a clock chart and the presence or absence of the Jack-in-the-box
Phenomenon may be useful for the early detection of traffic accidents caused byabnormal visual fields.
Once abnormal visual fields caused by glaucoma, etc. have progressed, it is difficult
to recover from them, so early detection and treatment are essential. However, since
the abnormal visual field progresses one eye at a time, it is challenging to recognize
abnormalities in the visual field of both eyes, making early detection difficult. Since
the clock chart detects abnormal visual fields in one eye, it is possible to detect andtreat them early. Even if abnormal fields of vision are found in both eyes, if it is only
a mild case, the driver can continue to drive by paying attention to places that areeasily overlooked while driving. Therefore, to prevent traffic accidents caused by30

abnormal visual fields, it was considered important first to know the state of one’s
visual field.
In addition, in the course of examining the implementation method of the clock
chart in this study, it became clear that there are individual differences in the way the
Marriott blind spot appears in different subjects and that the accuracy of the test varies
greatly depending on the instruction provided by the examiner. Therefore, it wasconsidered necessary to standardize the implementation method of the clock chart in amanual, etc., as well as to calibrate the method through prior training, etc., if multiple
examiners are to conduct it.
These results suggest that the clock chart may be helpful as a screening tool forabnormal visual fields. In addition, since many of those who had experienced traffic
accidents also experienced the “Jack-in-the-box Phenomenon,” it was considerednecessary to increase the number of subjects and conduct further studies to clarify the
relationship between these phenomena and traffic accidents in the future.

31

Ⅲ．《Research for FY2018》
Conducting Epidemiological Research Studies on
Occupational Drivers
1．Background and Objectives
In fiscal year 2018, based on the pilot study results conducted in fiscal year 2017, asurvey study using questionnaires and clock charts was conducted on approximately
2,000 occupational drivers. The purpose of this study was to clarify (1) the
relationship between daytime sleepiness and traffic accidents, (2) the relationshipbetween knowledge of hay fever medication and medication-taking behavior, and (3)the relationship between abnormal visual fields and traffic accidents.

2．Method
2-1．Target
This study was conducted from June to January FY 2018 on 1,921 employees of cab
companies and 89 employees of tanker companies in the Tokyo metropolitan area.
However, because the working conditions and traffic accident rates differ significantly
between employees at cab companies and employees at tanker companies, only
employees at cab companies, for whom we were able to secure a large number ofsubjects, were included in the analysis in this report.

This study was conducted withthe approval of a Medical Ethics Committee for Research at Juntendo University
School of Medicine (approval number: Jun Dai I Rin No. 2018053).
2-2．Questionnaire
In addition to general items (age (years old), gender, height (cm), weight (kg),sleeping hours, and working hours), the questionnaire also assessed the following:
daytime sleepiness, symptoms of hay fever, whether or not they were taking hay fever
medication, whether or not they had knowledge of the side effects of the medication,
whether or not they had stopped taking the medication, whether or not they were
driving a car or motorcycle, whether or not they had experienced the Jack-in-the-box
Phenomenon and the number of times they had been in a traffic accident. The samequestionnaire items for the Jack-in-the-box Phenomenon and traffic accident
experience were used as in the FY 2017 study. For the assessment of daytime
sleepiness, the Japanese version of the Epworth Sleepiness Scale (JESS) was used, anda score of 11 or higher was defined as a person with excessive daytime sleepiness. 2 8 )32

The details of the questionnaire survey items are shown in Appendix 1.
2-3．Clock Chart
The clock chart test was conducted under the examiner's instruction in the same way
as the survey method of the pilot study in FY 2017. Based on the survey conducted in
FY 2017, a clock chart implementation manual ( Appendix 2) was prepared to improve
the accuracy of the test, and the test was conducted following the manual procedures.
In addition, a clock chart recording sheet (Fig. 23) was used during the test, anddetailed records were made of the presence or absence of abnormal visual fields.
2-4．Statistical Analysis
JESS's association between daytime sleepiness and traffic accident experience wasanalyzed using multivariate adjustment logistic regression analysis adjusted for genderand age. The association between knowledge of hay fever medication and medicationtaking behavior was examined using the χ² test. Multivariate adjustment logistic
regression analysis adjusted for gender and age was used to analyze the relationshipbetween the Jack-in-the-box Phenomenon and the clock chart, the combination of theJack-in-the-box Phenomenon and the clock chart, and the experience of traffic
accidents. The statistical significance level was set at p<0.05. SAS Ver9.4.(SASInstitute Inc., Cary, NC, USA) was used as the statistical software.

33

Figure 23: Clock Chart Recording Sheet
34

3．Results
3-1．Characteristics of Target
Of the 1,921 cab company employees included in this study, 1,813 (94.5%) were male,and the mean age (standard deviation) was 50.7 years old (±12.1 years). 757 (39.8%)
were obese, 1,360 (71.5%) were habitual drinkers, and 752 (39.8%) were habitual
smokers. The number of occupational drivers was 1,568 (81.6%), and 1,030 (55.4%)
had been involved in a traffic accident within the past five years. Of the nine questions
related to the Jack-in-the-box Phenomenon, 663 (36.2%) answered “Yes” to at least
one question, and 303 (15.8%) had at least one abnormal visual field on either eye.
(Table 4)
Number ofPeople

Total

（％）

1,921

（100）

Male

1,813

(94.5)

Obese (BMI 25 kg/m2 or more)

757(39.8)

Habitual drinker

1,360(71.5)

Habitual smoker

752(39.8)

Glaucoma under treatment

16

(0.9)

People who snore

888(46.6)

105

(5.6)

1,568

(81.6)

1,030(55.4)

663(36.2)

303(15.8)

Those with excessive daytime sleepiness (JESS
score of 11 or higher)
Occupational driverThose who experienced a traffic accident in thepast 5 years
Those who experienced one or more Jack-in-thebox Phenomenon.
Those who have one or more abnormal visual field
findings by clock chart on either left or right eye.
Table 4: Characteristics of Target35

3-2．Relationship between Daytime Sleepiness and Traffic Accidents
To examine the relationship between daytime sleepiness and traffic accidents,
people without complete data on gender, age, previous traffic accidents, sleep
duration, JESS scores, and non-occupational drivers were excluded from the analysis,
and a total of 1,433 were subject to analysis. The gender-age adjusted odds ratio (95%
confidence interval) of experiencing a traffic accident among those with excessive
daytime sleepiness was 1.55 (0.92-2.61), and there was no significant increase in theodds ratio.
However, since the rate of those with excessive daytime sleepiness was as low as
5.6% in this study, we examined the relationship between the JESS scores in quartiles
and the experience of traffic accidents. The results showed that the gender and ageadjusted odds ratios (95% confidence intervals) for having been in a traffic accident
relative to the first quartile of JESS scores were 1.07 (0.80-1.42) for the second
quartile, 1.44 (1.06-1.96) for the third quartile, and 1.59 (1.17-2.15) for the fourth
quartile. As the JESS score increased, there was a significant increase in the odds ratioof having experienced a traffic accident (Fig. 24).
Gender and age adjusted odds ratio

Numb er ofPeop le: 412
Case: 229 p eop leFirst Quartile
1 (0-2)

Numb er ofPeop le: 370
Case: 213 p eop le

Second Quartile
4 (3-4)

Numb er ofPeop le: 309
Case: 202 p eop le

Third Quartile
5 (5-6)

Numb er ofPeop le: 342
Case: 234 p eop leFourth Quartile
8 (7-24)

ESS Score Quartiles Median(Minimum- Maximum)
Logistic Regression Analysis

Figure 24: Relationship between Daytime Sleepiness and Traffic Accidents36

3-3．Relationship between Knowledge of Hay Fever Medication and Medication
Behavior
To examine the relationship between knowledge of hay fever medication andmedication taking behavior, people without complete data on gender, age, sleepinesscaused by hay fever, information on hay fever medication, and knowledge of hay fever
medication were excluded from the analysis, and a total of 1,694 were subject toanalysis.
3-3-1．Presence or Absence of Knowledge of Hay Fever Medications
Regarding the knowledge of hay fever medicines, in response to the question “Do you
know that hay fever and allergic rhinitis medicines can cause sleepiness as a side
effect?” 1,193 respondents (70.4%) answered “Yes. Also, in response to the question,“Do you know that there are medicines for hay fever and allergic rhinitis that do noteasily cause sleepiness as a side effect?” 850 respondents (50.2%) answered “Yes.”(Fig. 25).
Do you know that there are
medicines for hay fever andallergic rhinitis that do noteasily cause sleepiness as a

Do you know that hay fever
and allergic rhinitis medicines
can cause sleepiness as a side
effect?

No
No

Yes

Yes

Figure 25: Presence or Absence of Knowledge of Hay Fever Medications

3-3-2．Relationship between Knowledge of Hay Fever Medication and Taking
Medicine
In this study, 428 complainants who answered, “I sometimes have trouble withsleepiness or dullness when I have symptoms of seasonal hay fever or allergic
rhinitis,” were surveyed about the relationship between their knowledge of drugs that37

do not easily cause side effects of sleepiness and the rate of taking hay fever
medication. The percentage of hay fever sufferers taking medication was 59.1% among
those who answered: “yes” to the question “Do you know that there are medications
for hay fever and allergic rhinitis that do not easily cause sleepiness as a side effect?”.
In comparison, that of those who answered “no” was 39.4%, significantly lower thanthat of those who answered “yes” (P<0.01) (Fig. 26).
People with sleepiness due to hay fever: 428 people
Hay fever medication users(%)
X 2 Test

Yes (301 people)

No (127 people)

Do you know that there are medicines for hay fever and allergic
rhinitis that do not easily cause sleepiness as a side effect?

Figure 26: Relationship between Knowledge of Hay Fever Medication and Taking
Medicine

3-3-3．Relationship between Knowledge of Hay Fever Medication and Those Who
Stopped Taking Medication
In this study, 364 respondents taking hay fever medication were examined for the
relationship between their knowledge of drugs that do not easily cause sleepiness as aside effect and those who stopped taking it. Respondents who had taken hay fever
medication and had stopped taking their medication due to “sleepiness that interfereswith work” were asked, “Do you know that there are medications for hay fever andallergic rhinitis that do not easily cause sleepiness as a side effect?” 15.9% of the
respondents answered “yes” while 25.7% of the respondents answered “no.” The
percentage of discontinuers was significantly higher in the group with no medication
knowledge. (P=0.04) (Fig. 27)
People taking hay fever medication: 364
38 people

Those who stopped taking
medication due tosleepiness(%)
Yes (290 people)
X Test2

No (74 people)

Do you know that there are medicines for hay fever and allergic
rhinitis that do not easily cause sleepiness as a side effect?

Figure 27: Relationship between Knowledge of Hay Fever Medication and Those Who
Stopped Taking Medication

3-4．Relationship between Abnormal Visual Fields and Traffic Accidents
To analyze the relationship between abnormal visual fields and traffic accidents,
people without complete data on gender, age, experience of traffic accidents, Jack-inthe-box Phenomenon, and non-occupational drivers were excluded from the analysis,
and a total 1,475 were subject to analysis.
3-4-1．Relationship between the Jack-in-the-box Phenomenon and Traffic
Accidents
The number of respondents who answered “Yes” to the questions about the “Jack-inthe-box Phenomenon” within the past five years was divided into three groups: those
who answered zero yes, those who answered one or two yes, and those who answered
three or more yes. The relationship between the number of responses and theexperience of traffic accidents was examined using gender and age-adjusted logistic
regression analysis. As a result, the gender and age-adjusted odds rate (95%
confidence interval) for traffic accident experience in the group with one or two Jackin-the-box Phenomenon and the group with three or more Jack-in-the-box Phenomenon
was 1.61 (1.26-2.06) and 2.25 (1.53-3.30), respectively, compared to the group withzero Jack-in-the-box Phenomenon. A significant increase in the odds rate for traffic
39
Numb er ofPeop le: 921
Case: 517 p eop le

Numb er ofPeop le: 400
Case: 269 p eop le

Numb er ofPeop le: 154
Case: 114 p eop leaccident experience was observed as the number of Jack-in-the-box Phenomenon
increased (Fig. 28).
Gender and age adjusted odds rate
1 to 20
Logistic Regression Analysis

3 or more

The number of Jack-in-the-box Phenomenon

Figure 28: Relationship between the Jack-in-the box Phenomenon and Traffic
Accidents

3-4-2．Relationship between Clock Chart and Traffic Accidents
A clock chart was used to classify the presence or absence of at least one abnormal
visual field in either the left or right visual field, and gender- and age-adjusted logistic
regression analysis was used to examine the association with traffic accident
experience. The results showed that the gender-age adjusted odds ratio (95%
confidence interval) of experiencing a traffic accident in those with abnormal visual
fields compared to those without abnormal visual fields was 1.07 (0.8-1.42), and there
was no significant association between abnormal visual fields measured by the clock
chart and traffic accidents (Fig. 29).

40

Gender and age adjusted odds rate

Numb er ofPeop le: 242
Case: 145peop le

Numb er ofPeop le: 1,233
Case: 755 p eop le

Yes

No

One or more abnormal visual field findings by clock chart
Figure 29: Clock Chart and Traffic Accidents

3-4-3．Combination of Jack-in-the-box

Phenomenon and Clock Chart and its

Relation to Traffic Accidents
Those who answered “Yes” to at least one question about the Jack-in-the-box
Phenomenon within the past five years were defined as having the “Jack-in-the-box
Phenomenon, and those who showed at least one abnormal visual field in either theleft or right visual field measured by the clock chart were defined as having abnormal
visual field. The relationship between the combination of these factors and theexperience of traffic accidents was examined using gender and age-adjusted logistic
regression analysis. The results showed that the gender and age-adjusted odds ratios(95% confidence intervals) of having been in a traffic accident in the group with only
the Jack-in-the-box Phenomenon, the group with only abnormal visual fields, and thegroup with both the Jack-in-the-Box Phenomenon and abnormal visual fields were1.72 (1.35-2.21), 1.00 (0.69-1.44), and 1.88 (1.20-2.95), compared to the group withneither the Jack-in-the-Box Phenomenon nor abnormal visual fields. There was asignificant increase in the odds ratio of having been in a traffic accident when there
was only the Jack-in-the-box Phenomenon or both the Jack-in-the-box Phenomenon
and abnormal visual field. (Fig. 30)

41

Gender and age adjusted
odds rate

Numb er ofPeop le: 781
Case: 442 p eop le

Numb er ofPeop le: 452
Case: 313 p eop le

Numb er ofPeop le: 140
Case: 75 p eop le

Numb er ofPeop le: 102
Case: 70 p eop le

N o vi s u a l f i e l d d i f i c i t s

N o vi s u a l f i e l d d i f i c i t s

W i t h vi s u a l f i e l d d i f i c i t s

W i t h vi s u a l f i e l d d i f i c i t s

N o ja ck -in -th e- jox

Wih h ja ck -in - th e- jox

N o ja ck -in -th e- jox

Wi th ja ck- in -th e- jox

p h e o n om e n on

p h e o n om e n on

p h e o n om e n on

p h e o n om e n on

Logistic Regression Analysis

Combination of visual deficits and the jack-in-the box phenomenon
Abnormal visual field: Sujbects with one or more abnormal visual field
findings detected with the clock chart.

Figure 30: Combination of One or More Visual Field Deficit Findings detected with
Clock Chart and the Jack-in-the-box Phenomenon and Its Association with Traffic
Accidents

In addition, those who answered “yes” to at least one of the questions regarding theJack-in-the-box Phenomenon within the past five years were defined as having a Jackin-the-box Phenomenon, and those who showed three or more abnormal visual fields ineither the left or right visual field on the clock chart were defined as having abnormal
visual fields. The relationship between the combination of these factors and theexperience of traffic accidents was examined using gender and age-adjusted logistic
regression analysis (those with one or two abnormal visual field findings on the clock
chart were excluded). The results showed that the gender and age-adjusted odds ratios(95% confidence intervals) of having been in a traffic accident in the group with only
the Jack-in-the-box Phenomenon, the group with only abnormal visual fields, and thegroup with both the Jack-in-the-box Phenomenon and abnormal visual fields were 1.73
(1.35-2.21), 0.97 (0.58-1.61), and 2.66 (1.35-5.25), respectively, compared to thegroup with neither the Jack-in-the-box Phenomenon nor abnormal visual fields. There
was a significant increase in the odds ratio of having been in a traffic accident when
there was a Jack-in-the-box Phenomenon alone or when there was both a Jack-in-thebox Phenomenon and an abnormal visual field, and the risk increased more when there
was an abnormal visual field than when there was a Jack-in-the-box Phenomenon alone(Fig. 31).
42

Gender and age adjusted
odds rate

Numb er ofPeop le: 781
Case: 442 p eop le

Numb er ofPeop le: 452
Case: 313 p eop le

N o vi s u a l f i e l d d i f i c i t s

N o vi s u a l f i e l d d i f i c i t s

N o ja ck -in -th e- jox

Wih h ja ck -in - th e- jox

p h e o n om e n on

p h e o n om e n on

Numb er ofPeop le: 68
Case: 35 p eop le

3 or m or e v i s u a l f i e l ddi fi ci t s
N o ja ck -in -th e- jox
p h e o n om e n on

Numb er ofPeop le: 47
Case: 35 p eop le

3 or m or e v i s u a l f i e l ddi fi ci t s
Wi th ja ck- in -th e- jox
p h e o n om e n on

Combination of 3 or more visual deficits and the jack-in-the box
phenomenondetected with the clock chart.
Logistic Regression Analysis*Sujbects with one or two abnormal visual field findings detected with the clock chart were excluded.

Figure 31: Combination of Three or More Abnormal Visual Field Findings detectedwith Clock Chart and Jack-in-the-box Phenomenon and Its Association with
Traffic Accidents

43

4．Conclusion
4-1．Relationship between Daytime Sleepiness and Traffic Accidents
Daytime sleepiness is one of the major risk factors for traffic accidents, and thepercentage of accidents caused by driver sleepiness is said to account for 10-30% of
all accidents. 2 9 -3 1 ) In the report by Sakurai et al., ESS scores were higher in those who
had a history of serious accidents than in those who had not, among those who had
visited a sleep medicine specialist with a principal complaint of sleep apnea. 3 2 ) In
addition, the study reported that the ratio of serious accidents was 11.4 times higher inthe obese, severe SAS, and severe daytime sleepiness groups than in the group without
these factors. 3 2 ) In this study, the association between daytime sleepiness assessed by
the JESS and experience of traffic accidents was examined. In the association between
JESS score quartiles and experience of traffic accidents, a significant increase in theodds ratio of traffic accident experience was observed in the third quartile and above,
where the median (minimum-maximum) score was 5 (5-6) points. In the target groupof this study, the mean score (standard deviation) of the JESS was 4.7 (±3.4) points,
and the percentage of those with excessive daytime sleepiness was 5.6%. In theprevious study that examined the prevalence of excessive daytime sleepiness inJapanese community residents, the percentage of men in their 20s to 60s who hadexcessive daytime sleepiness was reported to be 9.1%, 3 3 ), suggesting that theprevalence in this study group is relatively low. One possible reason for this was that
the JESS and other questionnaires were not anonymized in this study and thus may
have been underestimated due to reporting bias. These results suggest that JESS
assessment may be helpful for traffic accident prevention. On the other hand, it isnecessary to carefully consider the cutoff of JESS when conducting JESS assessment
in a non-anonymous manner at transportation companies, as in this study.
4-2．Relationship between Knowledge of Hay Fever Medication and Medication
Taking Behavior
In this study, the relationship between knowledge of hay fever medication andmedication-taking behavior was examined. The results showed that among those whocomplained of sleepiness and dullness due to hay fever, the percentage of taking
medication was significantly lower among those who did not know about hay fever
medication, which does not easily cause sleepiness, and the percentage of
discontinuing medication was significantly higher among those who did not haveknowledge of the medication. Also, the high percentage of those who did not know
44about drugs that were particularly difficult to cause sleepiness suggests that theamount of information about non-sedating drugs is not sufficient for those working intransportation companies, and their impressions of the side effects of therapeutic drugs
may precede them, leading to lost opportunities for drug selection and decreased
adherence to medication.

Since hay fever has a high prevalence among working-age

people, and the decline in QOL during the daytime affects work productivity, it wasconsidered necessary to provide appropriate treatment for symptom relief when hay
fever symptoms are present and promote appropriate medication behavior for thispurpose. It was considered necessary to promote and raise awareness of appropriate
medication knowledge, especially for occupational drivers, because discontinuation of
medication without choosing appropriate treatment may affect driving without
reducing symptoms.
4-3．Relationship between Abnormal Visual Fields and Traffic Accidents
In an aging society, abnormal visual fields are a risk factor for traffic accidents.
Previous studies have shown that glaucoma patients have a higher risk of traffic
accidents. 1 4 -1 6 ) Therefore, early detection of abnormal visual fields is important inpreventing traffic accidents. In this study, the relationship between the Jack-in-the-box
Phenomenon and traffic accident experience was examined, and the percentage of
those who had experienced traffic accidents was significantly higher among those who
had experienced the Jack-in-the-box Phenomenon more frequently. This suggests thatthe evaluation of the Jack-in-the-box Phenomenon may be a useful tool for traffic
accident countermeasures in the transportation industry. On the other hand, there wasno significant association between abnormal visual fields detected with clock chartsand experience of traffic accidents in this study. The possibility that the abnormal
visual fields assessed by the clock chart are overestimated is a possible reason for this.
Specifically, this clock chart test took about 10 minutes. The subject complained that
it was difficult to maintain posture and eye opening. The eyelids drooped due tofatigue, which may have led to overestimating the upper abnormal field of vision.
15.8% of the subjects in this study had abnormal visual fields detected with the clock
chart. However, the prevalence of glaucoma, the leading cause of abnormal visual
fields, was reported to be about 5% in people over 40 years old in a previous study. 11 )Therefore, it is possible that many false-positive subjects were included in theevaluation of abnormal visual fields with the clock chart. In this study, however, thecombination of the presence or absence of the Jack-in-the-box Phenomenon and thepresence or absence of abnormal visual field detected with the clock chart was45

examined. The percentage of subjects with the Jack-in-the-Box Phenomenon and at
least one abnormal visual field detected with the clock chart was 6.9%, similar to theprevalence of glaucoma. As a result of examining the relationship between the
combination of these factors and the experience of traffic accidents, a significant
increase in the risk of experiencing traffic accidents was observed in those who had
experienced Jack-in-the-box Phenomenon and traffic accidents. These results indicatethat the combination of the Jack-in-the-box Phenomenon and the clock chart test may
be useful as a preventive measure against traffic accidents caused by abnormal visual
fields. In particular, the clock chart test can detect abnormal visual field in one eye at
an early stage, before the abnormal visual field in both eyes occurs, making it possible
to start treatment before the abnormal visual field progresses.

Even if an abnormal

visual field is found in both eyes, if the abnormality is mild, it is possible to prevent
traffic accidents by giving instructions such as, “You may miss a traffic light or a stop
sign. Be careful on the roads you often take and avoid going on unfamiliar roads if
possible.” In order to prevent traffic accidents caused by abnormal visual fields, it isfirst and foremost essential to be aware of one’s visual field abnormalities.

46

Ⅳ．《Research for FY2019》
Conducting Follow-up surveys for those with
Findings on Clock Chart
1．Background and Objectives
In the survey on health-related accidents conducted in FY 2018 on approximately
2,000 occupational drivers, the test results were reported to those with findings on theclock chart, a simple screening system for abnormal visual fields andrecommendations were made to them to visit an ophthalmologist (see Appendix 3). In
FY2019, research was conducted to investigate the status of visits to ophthalmologists
by subjects with clock chart findings and examine the usefulness of screening forabnormal visual fields using clock charts.

2．Method
In this study, of the 1,921 employees of cab companies and 89 employees of tanker
companies who were surveyed on health-related accidents in FY2018, 326 employees
who were employed by those companies at the time of the survey in FY2019 and who
had abnormal visual fields detected by the clock chart test were surveyed. In thesurvey items of the Medical Checkup Status Survey Form, it was confirmed whether or
not the subjects had received ophthalmological checkups when they had received
checkups, the name of the diagnosis, the reason for not receiving checkups, and theintention of those who had not received checkups to receive checkups in the future(see Appendix 4 for details).
This survey started in July of 2019, and a reminder of the survey was sent out in
September. In November, a promotional flyer (see Appendix 5) was distributed tothose who had abnormal visual fields and the Jack-in-the-box Phenomenon to remindthem further to seek medical attention. From December, individual interviews were
held at each office for those who had not responded to the medical checkup survey
form, and the survey was finally conducted up to February 2020. This study was
conducted with the approval of a Medical Ethics Committee for Research at Juntendo
University School of Medicine (approval number: Jun Dai I Rin No. 2019059).

47

3．Results
Of the 326 subjects of this survey, questionnaires were collected from 216 people( 66.3%). Of these, 71 (32.9% of the questionnaire respondents) had visited theophthalmologist, and of these, 14 (19.7% of visitors to the ophthalmologist) had been
diagnosed with glaucoma. (Fig. 32)
On the other hand, 91 people ( 27.9%) did not respond to this survey, and 19 people(5.8%) dropped out of the follow-up survey due to retirement or other reasons during
the survey period.

Figure 32: A Breakdown of Follow-up Survey Questionnaire Replies and Responses

When those who returned the questionnaire in this survey but did not visit theophthalmologist (145 people) were asked the reason, the most common answer was“Too much trouble” (52 people), followed by “No time” (50 people) and “Others” (49people). (Fig. 33) Other free comments included “I didn’t understand the explanation
at the time of the clock chart test,” “I have doubts about the method and results of theclock chart test,” “I didn’t think my condition was bad enough to see a doctor/ I do not
see the need based on the results of the test,” “I am not aware of it/ I don’t feel any
abnormality in my vision,” “I don’t consider it to be subject to treatment/ I didn’tknow about it,” and “I think I have another disease, not glaucoma.”48

Figure 33: Reasons for not receiving medical examination

4．Conclusion
In this study, 326 of the 2,010 employees of the transportation companies surveyed in
FY 2018 were found to have abnormal visual fields detected by the clock chart test. Of
these, 14 out of 71 (19.7%) who visited the ophthalmologist were actually diagnosed
with glaucoma. Therefore, it could be estimated that if all of the 326 subjects withabnormal visual fields detected using the clock chart were to visit the ophthalmologist,
the number of those who would be diagnosed with glaucoma would be approximately
64. In addition, it could be estimated that about 3% of the 2,010 employees of thetransportation companies targeted in this study were potential glaucoma patients.
The prevalence of glaucoma in Japan is reported to be 5% in people over 40 years ofage, 11 ) . The results of this study approximated the prevalence of previous studies,indicating the possibility that a screening test for glaucoma uses a screening test using
a clock chart for occupational drivers may be helpful.
One of the subjects who visited an ophthalmologist as a result of this study and wasdiagnosed with glaucoma said, “Although it was a simple test, I had signs of glaucoma
and decided to visit an ophthalmologist. I am glad that I was able to be detected at an
early stage,” and “I would like this test to be included in the annual health checkup
because it does not take much time. The significance of this study was considered to
be great in that it provided an opportunity for early detection and treatment ofglaucoma, which is a disease that is difficult to be aware of. However, only about 20%
49

of those with clock chart findings actually visited ophthalmologists in this survey, andeven among those who responded to the medical checkup status questionnaire, about
60% did not visit ophthalmologists due to reasons such as “lack of time” or “too muchtrouble. Since there are few subjective symptoms of abnormal visual fields caused byglaucoma, it is difficult for individuals to recognize the disease's effects. Since theimpact on driving is not sufficiently known, it may be difficult for them to seek
medical attention. In the future, promoting awareness of the effects of glaucoma on
traffic accidents and preventive measures, especially at transportation companies, wasconsidered necessary.

Ⅴ．《Implementation in FY2019》
Raising Awareness of the Prevention of Healthrelated Accidents by Holding Symposiums andLectures1．Holding Symposiums
In FY2019, a traffic safety symposium (Appendix 6) and a special lecture (Appendix
7 ) were held to spread awareness of the prevention of health-related accidents, basedon the knowledge obtained in this research project so far. The details of each activity
are outlined below.
1-1.

Traffic Safety Symposium・Theme: “Prevention and Countermeasures for Health-related Accidents・Time and Date: 2 p.m. to 4:40 p.m. on Tuesday, December 10, 2019
・Place: Ehime Prefectural Medical Practitioners Hall, 4F Conference Room 1・Number of Participants: 81
・Contents of the symposium
Speaker (Affiliation): Takeshi Tanigawa (Professor, Course of Public Health,Juntendo University Graduate School of Medicine)
Topic: Sleep Apnea and Health-Related Accidents
Main Content:
Sleep apnea and health-caused accidents: Sleep apnea is a risk factor for traffic
accidents, and the risk is even higher if untreated. However, since sleep apnea is
not subjective, the importance of screening with objective indicators was pointedout.
50

Speaker (Affiliation): Shiho Kunimatsu (Vice President of Inoue Eye Hospital in
Nishikasai)
Topic: Narrowed Visual Field and Health-related Accidents
Main Content:
The current status of abnormal visual fields and health-related accidents in Japan:
While the prevalence of glaucoma, which causes abnormal visual fields, is high,many patients are unaware and untreated due to lack of subjective symptoms.
Therefore, it was pointed out that early detection and treatment are important. In
addition, cases and judicial precedents of traffic accidents caused by abnormal
visual fields were introduced, and the first outpatient driving clinic in Japan was
also introduced.
Speaker (Affiliation) : Kazuko Okamura (Director, Research Office, National
Research Institute of Police Science)
Topic: Health factors inferred from traffic autopsy cases
Main Content:
The results of autopsies on traffic accident fatalities in Chiba Prefecture werereported. The report showed a high percentage of pedestrians and bicyclists
involved in traffic accidents, a high percentage of victims living alone or withlifestyle-related diseases or mental illness, and a high percentage of offenders using
alcohol or drugs.
Speaker (Affiliation) : Migiwa Asano (Professor, Department of Forensic Medicine,
Ehime University Graduate School of Medicine)
Topic: Health-related Accidents from the Perspective of Forensic Medicine
Main Content:
The causes of sudden death while driving in Japan were reported. In addition,
actual cases that were determined by autopsy to be deaths due to illness or
accidents were reported. Also, examples of the use of forensic medicine for traffic
accident countermeasures were reported.
Speaker (Affiliation) : Katsutoshi Ishida (Manager, Safety Policy Division,
Automobile Bureau, Ministry of Land, Infrastructure, Transport, and Tourism)
Topic: Prevention of Health-Related Accidents
Main Content:51

A report was given on the outline of measures to prevent health-related accidents inJapan. It was reported that while the overall number of traffic accidents has been
decreasing in recent years, the number of health-related accidents continues toincrease due to the increase in the number of elderly drivers. In addition, a report
was made on the efforts of the Ministry of Land, Infrastructure, Transport, andTourism to develop a health management manual for drivers of commercial vehicles
and on the status of screening for sleep apnea and brain diseases.

From left, Mr. Ishida, Dr. Kunimatsu, Dr. Tanigawa, Dr. Asano, Ms. Okamura

52

1-2.

Special Lecture

・Topic: “Prevention of and Countermeasures for Health-Related Accidents -Abnormal
Visual Field and Traffic Accidents-”
・Time and Date: 6 p.m. to 8:05 p.m. on Wednesday, February 19, 2020
・Place: Juntendo University, Century Tower 8F, Large Classroom
・Number of Participants: 74
・Content of the Lecture
Speaker (Affiliation): Kiyohide Tomooka (Associate Professor, Course of Public
Health, Juntendo University School of Medicine)
Topic: Visual Field Defect and Daytime Sleepiness on Motor Vehicle Crashes
Main Content:
Findings from this research project suggested that having both abnormal visual
fields and daytime sleepiness significantly increased the risk of traffic accidents
compared to those who did not have them.
Speaker (Affiliation): Shiho Kunimatsu (Vice President of Inoue Eye Hospital in
Nishikasai)
Topic: Narrowed Visual Field and Health-related Accidents
Main Content:
Concerning the relationship between narrowed visual field and health-caused
accidents, cases of driving performance of glaucoma patients using a driving
simulator in Japan’s first outpatient driving clinic were reported.
Speaker (Affiliation): David Crabb（Professor, Statistics and Vision Research,
City, University of London）
Topic: Glaucoma and age-related macular degeneration ―through the eyes andsteering wheel of the patient―
Main Content

53

A study on the relationship between abnormal visual fields caused by glaucoma or
age-related macular degeneration and driving performance was reported. Since
glaucoma patients are considered to be affected by abnormal visual fields in various
aspects of their daily lives, quantitative performance measurements were taken forvarious daily tasks such as driving acar. It was reported that abnormal
visual fields affect theirperformance and that the location of
the abnormal visual field has a
specific impact on driving
performance. Since the populationof patients with abnormal visual
fields is expected to increase in an
aging society, the importance of developing new technologies such as autopilot waspointed out.

2．Results of Promotion Activities-Results of the Symposium
Questionnaire2-1.

Traffic Safety Symposium

A questionnaire survey was conducted among the participants of this symposium, and62 people responded. In response to the question, “Before participating in this
symposium, did you know that sleep apnea can cause traffic accidents?”, 69% of the
respondents answered, “I knew a lot about it.” or “I knew a little about it” (Fig. 34).

54

Figure 34: Before participating in this symposium, did you know that sleep apnea

can cause traffic accidents?
In addition, the percentage of respondents who answered “very necessary” and“somewhat necessary” to the question, “Do you think that the screening tests for sleep
apnea are necessary to prevent traffic accidents?” was 69% before the symposium and
95% after the symposium, showing a significant increase. (Fig. 35)

55

Figure 35: Do you think that screening tests for sleep apnea are necessary to

prevent traffic accidents?
In response to the question “Before participating in the symposium, did you knowthat glaucoma can cause traffic accidents?”, 34% of the respondents answered, “I knew
a lot about it.” or “I knew a little about it.” (Fig. 36).

56

Figure 36: Before participating in the symposium, did you know that glaucoma cancause traffic accidents?
The percentage of respondents who answered “Very necessary” and “Somewhat
necessary” to the question “Do you think that screening tests for glaucoma arenecessary to prevent traffic accidents?”, 60% of the respondents answered “verynecessary” or “somewhat necessary” before the symposium, but the percentage
increased significantly to 95% after the symposium. (Fig. 37)

57

Figure 37: Do you think that screening tests for glaucoma are necessary to prevent

traffic accidents?
To the question, “Did you find this symposium useful?”, 89% of the participants
answered, “very useful” or “somewhat useful” ( Fig. 38 ).

Figure 38: Do you find this symposium useful?

58

2-2.

Special Lecture

A questionnaire survey was conducted among the participants of this special
lecture, and 53 people responded. In response to the question, “Before attending thelecture, did you know that glaucoma can cause traffic accidents? 79% of the
respondents answered that they “I knew a lot about it” or “I knew a little about it.”(Fig. 39).

Figure 39: Before participating in the symposium, did you know that glaucoma

can cause traffic accidents?
In addition, the percentage of respondents who answered “Very necessary” or“Somewhat necessary” to the question “Do you think that screening tests for glaucoma
are necessary to prevent traffic accidents? increased significantly from 79% before thelecture to 96% after the lecture. (Fig. 40)

59

Figure 40: Do you think that screening tests for glaucoma are necessary to prevent
traffic accidents?

To the question “Did you find this symposium useful?”, 100% of the participants
answered, “very useful” or “somewhat useful.” (Fig. 41)

Figure 41: Did you find this symposium useful?

60

3．Conclusion
The results of the symposium questionnaire showed that about 70% of the participants
knew that sleep apnea could be a cause of health-caused accidents. In comparison,
only about 30% knew that glaucoma could be a cause of health-caused accidents. In
the special lecture, about 80% of the participants answered that they knew about it to
the same question, which may be because most of the participants were
ophthalmologists and researchers. Therefore, it is necessary to raise awareness among
the general public, especially operation managers in the transportation industry, of thepossibility of these diseases causing health-related accidents further. Furthermore, afurther empirical study for the social implementation of screening to prevent healthrelated accidents caused by sleep apnea, abnormal visual fields, etc., was considerednecessary.

In addition, since sufficient measures have not been taken for health-related accidents, not only in Japan but also in other countries, especially in Asia, it
was considered necessary to develop international public awareness activities based on
the findings of this study.

61

Ⅵ．Conclusion and Issues
1．Summary of this StudyIn this project, focusing on sleep-apnea, glaucoma, and sleepiness caused by hay fever
as causes of health-related accidents, we have been conducting research to clarify the
relationship between these health disorders and traffic accidents and to establish andpromote awareness of countermeasures against health-related accidents.
In FY 2017, a pilot study was conducted on 14 ophthalmology outpatients to
examine the method using the clock chart, a simple screening tool for abnormal visual
fields. As a result, in almost all cases, the findings of an abnormal visual field foundby using the clock chart and the abnormal areas found by using the Humphrey
automated visual field test were generally matched. In addition, three out of four
patients who had experienced a traffic accident within the past five years experienced
the Jack-in-the-box Phenomenon. This indicates that the clock chart may be useful as ascreening tool for detecting abnormal visual fields. Combining the clock chart testwith experience of the Jack-in-the-box Phenomenon may be helpful for early detectionof traffic accidents caused by abnormal visual fields.
In FY 2018, based on the pilot study results in FY 2017, a questionnaire on healthrelated accidents and a survey study using a clock chart were conducted on
approximately 2,000 employees of transportation companies. As a result, therelationship between daytime sleepiness assessed by the JESS and the experience oftraffic accidents was examined. Those with higher JESS scores had a significantly
increased risk of experiencing traffic accidents, suggesting that those with highdaytime sleepiness need to exercise caution against traffic accidents. As a result of
examining the relationship between knowledge of hay fever medication andmedication-taking behavior, it was discovered that among those who complained ofsleepiness and dullness due to hay fever, the percentage of taking medication was
significantly lower among those who did not know hay fever medication, which isdifficult to cause sleepiness; among those who were taking therapeutic medication, thepercentage of discontinuing medication was significantly higher among those who did
not know therapeutic medication. This suggests that promoting the correct knowledgeof hay fever remedies is necessary for appropriate treatment of hay fever. The results
showed that the risk of experiencing a traffic accident increased significantly for those
who had the Jack-in-the-box Phenomenon and abnormal visual fields as assessed by62

the clock chart test, compared to those who did not have both. This suggests that the
combination of the clock chart test and the questionnaire on the Jack-in-the-box
Phenomenon may be useful in preventing traffic accidents caused by abnormal visual
fields.
In FY2019, we surveyed the status of ophthalmological checkups for 326 subjects withfindings on the clock chart test among the subjects surveyed in FY 2018. As a result,
14 (19.7%) of the 71 subjects who visited the ophthalmologist were diagnosed withglaucoma. From this, it could be inferred that 64 (about 3%) of the 1,921 employees of
the transportation companies subject to this study were considered potential glaucoma
patients. The results of this study are similar to the prevalence of glaucoma in Japan(about 5% of people over 40 years old), suggesting the usefulness of the clock chart
test for screening glaucoma.
As a result of the empirical research for the prevention of health-related accidents
conducted by this research project over three years, the following relationships wereidentified: the relationship between daytime sleepiness and traffic accidents, therelationship between knowledge of hay fever medication and medication-taking
behavior, and the relationship between abnormal visual fields and traffic accidents. In
particular, there have been no large-scale epidemiological studies on the relationshipbetween abnormal visual fields and traffic accidents using the clock chart test, asimple screening tool for abnormal visual fields. In addition, the clock chart is
simpler, cheaper, and quicker to use than standard visual field tests, making it easier
to implement at transportation companies. This research project is considered ameaningful study in the prevention of health-related accidents.
Additionally, based on the results of the three-year research project, a traffic
symposium and a special lecture were held in FY2019 with the aim of raisingawareness of the prevention of health-related accidents. While it was revealed that thegeneral public was not very familiar with the fact that glaucoma can cause traffic
accidents in contrast to sleep apnea, the percentage of respondents who answered thatscreening for sleep apnea and glaucoma was necessary to prevent traffic accidents
increased significantly before and after the symposium and the special lecture. Thissuggests that this research project effectively raised awareness of preventing healthrelated accidents.

2．Aiming to reduce health-related accidents
Needless to say, prevention of health-related accidents is essential not only for63

individual efforts but also for the support and efforts of families and workplaces andthe establishment of a social system that supports these efforts. Sleep apnea syndrome,
the subject of this study, has been increasingly recognized as a causative disease ofhealth-related accidents. Screening using objective indicators has become widespreadat transportation companies in recent years. However, it is still not fully developed insociety as a whole. Although the cab companies surveyed in this study were aware of
the importance of screening for sleep apnea, they had not yet implemented it.
Furthermore, few countermeasures are currently taken for glaucoma, and it is hardly
recognized as a causative disease of health-related accidents. Moreover, as for hay
fever, which is regarded as a national disease, proper knowledge about taking hay
fever medication was not sufficiently widespread. Therefore, in the future, it will beessential to promote and raise awareness of the actual situation and knowledge about
these diseases by providing such information to workplaces and the entire communityand developing and expanding screening systems for early detection and treatment,
especially for occupational drivers.
In recent years, lifestyle-related diseases, which are the cause of health-related
accidents, have become more prevalent in developed countries and developing
countries in Asia and other regions, making countermeasures against health-related
accidents an important public health issue in these regions as well. In order tounderstand the current status of health-related accidents in China, the world’s largest
car manufacturing country, and Thailand, which has the highest traffic accident rate in
the world, we exchanged opinions with experts in these countries at the end of
FY2019. As a result, it became clear that measures to prevent health-related accidents
in these countries were almost completely untouched. In the future, it is necessary to
conduct joint empirical research in each country based on the knowledge of healthrelated accident countermeasures obtained in this research project and developinternational dissemination and awareness.

64

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Appendix 1 Questionnaire

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Appendix 2 Clock Chart Implementation Manual

Clock Chart Implementation Manual■Items to be prepared(1) Clock Chart Recording Sheet(2) Clock Chart(3) Underlay for clock chart(4) Thumbtack for clock chart(5) Reference stick for clock chart (35cm)(6) Eye patch to be applied (eye patch)(7) Writing utensils(viii) Masking tape (used to fix the clock chart stand to the desk)(9) Trash bag■Method of Implementing Clock Chart Test・First, check the name of the office, name, and date of test.
(1) “Now, we are going to do a simple test of your visual field called Clock Chart.
(Have the subject look at the clock chart at a height of about 35 cm.) Can you see
these four creatures: ladybug, caterpillar, butterfly, and cat?”(2) (Handing an eye patch to be applied to the subject) “Let’s start with the test of theright eye. Peel off the sticker on the back and put this eye patch on your left eye.”*If the subject is wearing glasses, remove them once and apply the eye patch, thenhave the subject put on the glasses again. (Note, however, that the frame may
overlap the illustration during the test, making it difficult to see.)(3) “(Place A at 12 o’clock position on the clock chart.) “First, look at the clock chartfrom right above the center of the chart ● at this height with your right eye. (Use a
35 cm stick and have the subject look at the clock chart.)*When conducting the clock chart test on a desk, have the subject place both handson the desk to support the subject’s body.
*At that time, be sure to place a 35 cm stick near his/her eyes to keep a distance.
(4) “Can you see the picture of the caterpillar while staring at the center? If you can,make sure the caterpillar is in your field of vision while staring firmly at the center●“.” (Confirming that the picture of the caterpillar is no longer visible.) You don’t
see the caterpillar anymore. This is called a blind spot, and everyone has one. This
test is performed at the position of the eye where the blind spot appears, so please
maintain this position during the test. Also, we will check to see if you can see the73pictures of the creatures one by one, but please make sure you keep looking at thecenter ● during the test.”*If the eye follows the caterpillar, the caterpillar will not enter the blind spot, so
point to the center with a finger or other object and make sure to check if thecaterpillar disappears while looking at the center.
*If there is a range in the height of the eye at which the caterpillar disappears, it
should be closest to the height of 35 cm.
*Since the appearance of blind spots varies from person to person, if the subject
cannot find a blind spot, he or she should try looking for it by slightly raising or
lowering the height of the eyes.
*The key point of the clock chart test is to emphasize the need to maintain a heightof 35 cm and to keep looking at the center.
(5) “Let’s start with the ladybug.” " Is the picture of caterpillar disappeared with youreyes looking at the center ●?"➡Put a ✓ in the fixation point (1), and if the picture of the caterpillar disappears,
put a ✓ in the blind spot in the ladybug column.

(6) "Do you see a picture of the ladybug?"➡If visible, put a circle in 12 o'clock in the ladybug column; if not, put an X.
(7) Slowly turn A to the 1 o'clock position. Check in the same way as (7). In the sameway, check at the 2 o'clock to 11 o'clock positions. Also at 3 o'clock, 6 o'clock and9 o'clock positions, check the fixation points and put a ✓ in each of Fixation Points(2) to (4). (To confirm gazing at fixation point)

After finishing the ladybug, repeat steps (5) to (8) in the same order for thecaterpillar, butterfly, and cat. However, when testing of the caterpillar, it is normal
not to be able to see the caterpillar when A is at the 12 o'clock position because it
is a blind spot, so the corresponding box in the clock chart recording sheet isblacked out.
(8) " Then, looking at the center ● from directly above at the height where thecaterpillar disappears, does the center grid appear distorted? Also, does any of thepetals appear to be missing?" ➡Fill in the items for "distortion of the grid" and"missing petals" (If there is distortion or missing petals, put a circle in "Yes"; if74not, put a circle in "No").
After completing the test for the right eye, perform the test for the left eye. Coverthe right eye with an eye patch, place B at 12 o'clock position on the clock chart,and perform steps (3) through (8) for each creature, and then perform step (9).

75Notes on the Implementation of Clock Chart-Fix the clock chart base to the desk with tape. Also, use rubber gloves or finger sacks
to make it easier to rotate.
-At the start of the clock chart test (right eye A, left eye B at 12 o'clock position),stare at the center ● from right above and make sure that the caterpillar disappears(Marriott blind spot) before starting the test.
-It is also necessary to keep looking at the center at all times during the test. For thisreason, always check the fixation point.
-The test should be performed on each creature in the following order for both theright and left eyes, according to the recording sheet.
Ladybug → caterpillar → butterfly → cat-Stop rotating the clock chart every hour on the dial and make sure that the illustrationof each creature is in view.
-Always make sure that the caterpillar is out of sight first when working with eachcreature.
-Make sure to turn the clock chart to the right (clockwise) slowly.
-At the start (12 o'clock), when A for the right eye and B for the left eye are at the 3o'clock, 6 o'clock, and 9 o'clock positions, ask the subject to "look at the ● in thecenter." to confirm the fixation point.
-The same eye patch may be used for both the left and right eye, but if the eye has aninfectious disease such as stye, be sure to use a new patch for each eye.
-If the picture appears blurred or disappears due to the frame of the glasses, ask thesubject to shift the glasses in that position slightly by hand and check again if thepicture can be seen without overlapping the frame.
-If there are many findings at the top of the clock chart (1,2,1,0,11,12 o'clock), theeyelids may be lowered, and the subject may not be able to see. If this is the case,perform the test again with the eyelids properly opened.
-There are individual differences in the height of the blind spot (some people find theblind spot at a position that is more upward or downward than the 35 cm index, orleft or right of the center). However, basically, the measurement is performed withthe blind spot as the reference point. the entire clock chart should be in the field ofview.
・If the butterfly is not visible at the 3 o'clock position (for the right eye; 9 o'clock
for the left eye), the distance between the caterpillar and the butterfly is so close,making the appearance of the blind spot different for each individual. In such acase, if the cat in the periphery can be confirmed when it comes to the same76

position, the butterfly is considered to have entered the blind spot. Mark with X.

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Appendix 3 Clock Chart Result Sheet (Front)

Appendix 3 Clock Chart Result Sheet (Back)78

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Appendix 4 Medical Checkup Status Survey Form80

Appendix 5 Reminder to Those with Severe Findings
Appendix 6 Flyer for the Citizen's Symposium on Traffic Safety

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Appendix 7 Flyer on Special Lecture83