APPENDIX C

Initial Technica®@ Evaluation

Name: PF: Date

4.) How tong did it take before you were confident enough in the Technica® lenses to

use them routinely at work?

2.) Have you noticed anything different when working with these lenses for 4 weeks?

3.) Please rate your overall satisfaction with these lenses on a scale of 1-10, with 1

representing complete dissatisfaction and 10 representing complete satisfaction:

4.) Please check one choice for each of the following areas of lens performance:

Advantage Disadvantage
A) Variable Working Distance
B) Field of View
C)  Glare/Reflections
D) Vision (Distortion/Clarity)
E) Other:

5.) Please indicate any visuai symptoms that you noticed with these lenses:

Increased Decreased
A) Blurred Vision
B)  Eyestrain
Cc) Other:

Cl



Cho MH, Sjpear CH. Caplan L. The effect of
excessive add power on the acceptance of progres-
sive addition lenses. Journal of the American Op-

tometric Association. Sep 1991; 62(9):672-5.

Seppinni A, Mathe N. VDTs & your patient’s
health - symptoms and solutions. Computers in
Eyecare. Winter 1991-92; 1(2):26-8,42-3.

Bachman WG. Computer-specific spectacle Jens
design preference of presbyopic operators. Journal
of Occupational Medicine. Oct 1992;
34(10):1023-7.

10

lt

12

Sheedy JE. Prescribing for presbyopic computer
users, Eyecare Technology. Nov-Dec 1994;
4(6):57-9.

National Transportation Safety Board. Safety rec-
ommendation. Aug 11, 1989; A89-83 through -
90.

Wing H, Manning CA. Selection of air traffic
controllers: complexity, requirements and public
interest. Washington, DC: Department of Trans-
portation/Federal Aviation Administration; 1990,
FAA Report No. DCT/FAA-AM/90/13. Avail-
able from: National Technical Information Ser-
vice, Springfield, VA 22161.


Tue Use oF TasK-SPECIFIC LENSES
By PresByopic Air TRAFFIC CONTROLLERS
AT THE En Route Rapar ConsoLe

INTRODUCTION

The primary goal of the Air Traffic Control (ATC)
system, which is under the jurisdiction of the Federal
Aviation Administration (FAA), is to prevent colli-
sions between aircraft. This goal is achieved by pro-
viding a safe and orderly flow of air traffic, utilizing
the air space as efficiently as possible. An Air Traffic
Control Specialist (ATCS), or controller, is a person
authorized to provide air traffic control service ().

There are three basic ATC facilities: 1) Terminal
Radar System Area covers the airspace surrounding
designated airports; 2) Automated Flight Service Sta-
tion transmits weather, flight plan information, and
other assistance to pilots; and 3) Air Route Traffic
Control Center (ARTCC) provides air traffic control
during the en route phase of the flight between desig-
nated airport terminal areas.

Airways
Map

Plan View
Display

Alphanumeric
Keyboard

D Console

Figure 1: Schematic of the En Route Radar Console
(Note: Plan View Display is the radar display, while the D Console

holds flight progress strips).


Appendix C (cont.)
6.) Please indicate any physical symptoms that you noticed with these lenses:

Increased Decreased
A) Headaches
B) Neck Pair;
C) Back Pain
D) = Other:

7.) How do you fee! that working with these lenses has affected your work related stress? (please
check one)

1.) Increase greatly

2.) Increase slightly

3.) not affected

4.) decreased slightly

5.) decreased greatly

6.) have difficulty assessing.

{1
U1
{]
{]
t]
0]
8.)

How do you feel that using these len-es has affected your work efficiency? (please check one)

] 1.) Increase greatly

] 2.) Increase slightiy

] 3.) not affected

] 4.) decreased slightly

] 5.) decreased greatly

] 6.) have difficulty assessing.

.) How do you feel that using these lenses has affected your work related fatigue? (please check
e)

3

] 1.) Increase greatly

] 2.) Increase slightly

] 3.) not affected

] 4.) decreased slightly

] 5.) decreased greatly

J 6.) have difficulty assessing.

C2


APPENDIX E

Follow-up Evaluation

Name: Pit: Date

1.) Which tenses did you use at work?

{Please circle your answer) Technica® Old Lenses Both

2.) Please respond to each statement using the following scale:

1 =strongly agree
2= agree

3 =no difference

4= disagree

5 = strongly disagree

(If you circled “both” above, piease specify which lens or both for each question)

A) My eyeglass lenses make my job easier to perform: (lens: )
B) My eyeglass lenses allow me to see my entire work area clearly : (lens:
C) My eyeglass lenses allow me to work more efficiently: (lens: )
D) My eyeglass lenses help me to feel less tired at the end of the day: (lens:
—______)

E) ly eyeglass lenses have helped to reduce physical discomfort (headaches, neck pain, back
pain, etc.): (lens:

F) When | get a new pair of glasses, | would like to get the same eyegiass lenses that | am wearing
now: (lens:

Comments:

El
HU,S, GOVERNMENT PRINTING OFFICE: 1997 - 559-879/2003)



Appendix B (cont.)

Confirm Prescriptions:
Was written Rx available for work Rx? yes / no
Work Rx:

Dates: Rx: i / Lenses:

Rx PD:

Lens style:

Rx: Distance
op:

Add

OS:

Seg or MRP location:
pupil center / mm below / mm above

Differences between Rx and lenses worn:

Home Rx:

Dates: Rx: f f Lenses:

Rx PD:

Lens style:

Rx: Distance
OD.

Add

OS:

Seg or MRP location:

pupil center / mm below / mm above

B2



RESULTS

Thirty senior ATCSs responded to ovr request to
be test subjects, but only thirteen (n = 13) qualified for
inclusion. The reasons for rejection included lack of
time working at the radar console (n = 12) (many
applicants were supervisors who spend limited time
controlling traffic at the radar console), medical dis-
qualification from working as controllers (n = 2), and
failure to follow up after their initial inquiry (n = 3).

The mean age of the 13 subjects was 45.6 + 5.9
years (range 36 - 55 years). By coincidence, all subjects
were male. The avcrage intermediate working dis-
tance as specified by the subjects was 88.9 cm 4 2.9 cm
(range 84.7 - 95.1 cm).

The preponderance of eyes were hyperopic (far-
sighted), with no subject exceeding 2.00 diopters (D)
of myopia (nearsighted) or hyperopia, and the major-
ity were near erametropia (no refractive error) with
corrections less than or equal to + 0.50 D. Ani-
sometropia (difference in refractive error of the two
eyes) did not exceed 0.87 D (spherical equivalent), and
the maximum astigmatism correction was -0.75 D.

Table 1 presents each subject’s preference by age,
type of fens correction worn, and add power required.
Subjects who used multifocal lenses (except those who
wore Executive lens designs), preferred the Technica®,
while most SV lens wearers preferred their current
lens design at work. All of the subjects who preferred
Technica® were > 44 years of age and had adds
powers > +1.25 D.

The ATCSs’ subjective complaints with their origi-
nal lens designs while at work are presented in Table
2. The most prominent symptoms reported included
blurred vision (10) and eyestrain (5). Table 3 presents
subjective complaints reported with the Technica® at
the radar console. The Technica® lens reduced eye-
strain in two of five subjects while inducing it in three
others. Blurred vision was eliminated in five of ten
subjects who had reported this problem with their
original lens designs. The most numerous subjective
complaints with the Technica® were from distortion
(8) and limited field of view (10).

Five of the 13 controllers (38.5%) reported that
vision through their original corrective lenses contrib-
uted to work-related stress. The five who subsequently

oe i 3 g
1 44 BIFOCAL (FT 28) + 1.25 Technica®
2 40 SINGLE VISION + 1.00 *
| 3 48 TRIFOCAL (EXEC) + 2.00 *
4 47 SINGLE VISION + 1.50 Technica®
5 49 BIFOCAL (EXEC) + 2.00 * |
6 51 BIFOCAL (FT 35) + 2.00 Technica®
7 : 36 SINGLE VISION + 1.00 *
8 45 SINGLE VISION + 1.00 *
9 53 SINGLE VISION + 2.50 * |
10 55 SINGLE VISION + 2.00 *
11 47 PROGRESSIVE + 1,50 Technica®
{_ 12 36 SINGLE VISION + 1.00 *
13 45 SINGLE VISION + 1.50 Technica®

Note: * Denotes Subject preferred current Rx.

Table 1:
Worn and Add Power

ATCS Preference of Lens Design by Age, Type of Lens Correction


FT-28, D-28 Bifocal FT-7/28 Trifocal

+ 28mm»

Executive Bifocal Executive Trifocal

( >

KY

Figure 2: Standard Bifocal and Trifocal Lenses


Atthe ARTCC, each airspace sector may have one
to three controllers assigned the function of separat-
ing aircraft. The radar controller issues altitude, head-
ing or airspeed changes to keep the aircraft separated.
The radar associate/nonradar controller assists by
separating aircraft that do not appear on the radar
display, updating flight progress strips, and assuming
aircraft separation responsibility if the radar display
malfunctions. The ARTCC, or en route, controller
must be “stress tolerant” and “attentive to detail” as
their occupation requires they maintain. current as-
sessment of the rapidly changing location of each
aircraft (in three-dimensional space) and their pro-
jected future locations relative to each other along
with other pertinent aircraft parameters (destination,
fuel, speed, etc.) (,).

The en route ATCSs have a work environment
with unusual visual demands (See Figure 1). The
configuration of their work station makes visual cor-
rection, particularly of older ATCSs, challenging as
conventional spectacle lens designs may often be un-
suitable (). Ophthalmic lenses are routinely prescribed
by eye doctors to correct for presbyopia, a normal
decrease in near vision focusing ability (accommoda-
tion) of the eye that occurs with age. The presbyopic
eye cannot change focus from far distance (20 feet and
beyond) to see closer objects clearly. That focusing
must be done using spectacles or contact lenses. Spec-
tacle lenses may be used to correct for neur vision
(normally prescribed at 14-16 inches) in the form of
single vision (SV) and multifocal lenses (See Figure 2).
Both distant and near vision can be corrected with
multifocal lenses of standard bifocal designs, while a
trifocal lens adds a correction for intermediate vision
(about 28-32 inches).

Progressive addition lenses (PALs) are specially
designed to correct presbyopia (See Figure 3), PALs
eliminate the bifocal or trifocal segment lines and
provide a continuous focus from far to intermediate
to near distances. PALs are popular due to their
aesthetics, clear viewing at all distances, and their
ability to eliminate image jumps or blurred zones
inherent in standard bifocal and trifocal lenses (). The

drawbacks to general-purpose PALs include a rela-
tively narrow vertical/horizontal intermediate and
uear vision zone, distortion in the lens periphery,
difficulty in fitting, higher ccst, and an extended
wearer adaptation period (5,,).

The en route radar console is similar to that of
computer and video display terminal (VDT), as it has
a video monitor and a keyboard. The American Op-
tical Corporation’s TruVision Technica® is a task-
specific, progressive power lens design that has been
shown in clinical trials to provide the computer user
with a more comfortable, usable correction than with
standard multifocal lens designs (,). The Technica®
has a narrow distant viewing area while providing
wider intermediate and near vision zones, as com-
pared to general-purpose PAL designs (6). The
Technica’s® aberration zones are pushed to the top of
the lens, while PALs have distortion near the bottom
of the lens. The other difference between Technica®
and general-purpose progressives is that, instead of
having the correction for distant vision at the center of
the lens, Technica® has the intermediate vision cor-
rection at that point (See Figure 3). Technica® was
designed to meet the needs of the typical computer
and VDT user who views a screen located ata distance
equal to 60-80% of their near add power, and at a
viewing angle 10 - 20° below straight-ahead gaze ().
Upon review of the en route radar console, it was
concluded that the work station environment was
similar enough to that of the VDT user to merit
evaluation of the Technica® lens as an occupational
fens to correct the vision of presbyopic ATCSs while
working at such a unit.

The objective of this study was to conduct subjec-
tive comparison of the performance of the Technica®
with the lens designs currently worn by presbyopic en
route ATCS at their work environment. The compari-
son was to determine whether the visual benefits of
the Technica’s® unique design could be transferred
from the VDT environment to the radar console
environment, thus increasing efficiency by reducing
work-related stress, fatigue, and the number of visual

and physical complaints of ATCSs at work.


Appendix B (cont.)

Differences between Rx and lenses worn:

VAs with current Rx:
Distance Intermediate Near
(distance to radar screen)

OD:

Os:

OU:

#1
Monocular PDs: Dist OD: Os:

Near OD: OS:
Vertical height to pupil center in frame selected for study:
oD: mm OS: mm
Record Specifications of frame selected for study:

Name: Manufacturer:

Eye: Bridge: Temple:

Color#1: (Technica®)

Color#2: (Other style)

Availability verified #1: #2:
Technica® fitting and cut-out verified:
Duplicate Rx: Rx Technica®
OD: OD:
Os: Os:
Add Add
Seg Ht OD:
os:

Complete orders for Technica® and duplicate work lenses and attach copies to this record.

B3



METHODS

Twenty (20) presbyopic ATCSs 35 years of age and
older who worked at the en route radar console a
minimum of 20 hours per week were to be selected.
After receiving approval for the testing by manage-
mentand union representatives, the Houston ARTCC
in Houston, TX, was selected as the test site. Contrac-
tual support was obtained for clinical and administra-
tive services (Krug Life Sciences of Houston, TX) and
ophthalmic manufacturing services (Duffens Optical
of Houston, TX).

An overview of the study was presented at control-
ler team briefings on-site and flyers were posted
throughout the Center. The offer of receiving two free
pairs of prescription eyeglasses encouraged participa-
tion. Interested controllers were initially interviewed
by telephone, during which the purpose of the study,
time schedule, qualifications, compensation, etc., were
discussed.

Selected subjects had to meet the following re-
quirements: 1) they must have had a complete vision
examination within the past 12 months; 2) they must
wear prescription lenses for near or intermediate vi-
sion while working at the en route radar console for at
least 20 hours per week; 3) the subject’s spectacle
prescriptions must meet the parameters available in
the Technica® lens (Note: No subject was ruled out
due to prescription specifications.); 4) they must have
anticipated being based in the Houston area for 12-
months after inclusion into the study; and 5) they
must consent to a medical screening ar the Center to
tule out any active ocular or systemic pathology,
which could affect their vision or refractive prescrip-
tion stability.

A copy of the description of the study and an
Informed Consent Sheet were mailed to all pre-
screened applicants. Qualified ATCSs were asked to
bring these forms, all eyeglasses and refractive pre-
scriptions, and workstation measurements to their
initial on-site visit. At this visit, the Informed Con-
sent Sheet was signed by each ATCS, an evaluation of
current lenses (likes, dislikes, limitations, problems,
etc.; See Appendix A), and subject information forms
were completed (hours at console, years working as an

ATCS, visual and physical complaints, medical his-
tory, ophthalmic measurements of the optical devices,
etc.; See Appendix B).

After analyzing each subject’s refractive prescrip-
tion and eyeglasses, an ophthalmic frame was selected
from a 10-frame fitting set. Two complete pairs of
eyeglasses were ordered in identical frames: one dupli-
cate of the original prescription lenses worn at the
radar console, and one pair of Technica® lenses.
There were two subjects who wore “over-the-counter”
monofocal lenses at the radar console, rather than the
refractive prescription from their mosr recent eye
exam. Duplicate eyeglasses dispensed for those two
subjects, were full-view SV lenses incorporating the
refractive correction of their most recent eye exam.
The completed eyeglasses were verified to ensure they
met both the American National Standards Institute
standards (ANSI Z80.1 - 1987, American National
Standards for ophthalmics - prescription ophthalmic
lenses - recommendations) and the requirements in
the American Optical’s TruVision Lifetime System of
Lenses® Fitting Manual.

A second visit to the Houston ARTCC was sched-
uled for each subject to dispense the completed eye-
glasses. During this visit the new spectacles were fitted
to each subject, adaptation and use of the Technica ®
lens design was explained, and instructions for the
periods of use for both pairs of eyeglasses were pro-
vided. Each subject was asked to wear the Technica®
lenses for near point leisure activities for one week. If
the subject felt comfortable with Technica® at the
end of the week, they were asked to wear the Technica®
exclusively while working at the radar console for a 4-
week period. At the end of this period, each subject
was personally interviewed by means of an initial
Technica® evaluation questionnaire (See Appendix
C). During the fifth week, the subjects were asked to
alternate between the new version of their original
lenses (i.e., current fens design) and Technica® at
work. At the end of that week, a second comparative
experience survey (See Appendix D) was adminis-
tered. A final follow-up evaluation (See Appendix E)
was compleved three months later to verify any change
in lens design preference at work.


DOTEAAIAM-96127 The Use of Task-Specific
Office of Aviation Medicine Lenses by Presbyopic Air
Washington, D.C. 20591 Traffic Controllers at the

En Route Radar Console

Van B. Nakagawara
Kathryn J. Wood

Civil Aeromedical Institute
Federal Aviation Administration
Oklahoma City, Oklahoma 73125

December 1996

Final Report ents sovicnt gia oe an

Approved fsx public rebecse;
Distribution Unitmited

This document is available to the public
through the National Technical Information
Service, Springfield, Virginia 22161.

A) 5

U.S. Department
of Transportation

Federal Aviation
Administration

ATQSLGT SRD 4 |

19970122 110



general, the ATCSs preferred their original lenses if
they incorporated near and/or intermediate segments
with large surface areas, such as the bifocal and trifocal
executive (current: Technica® = 2:0) or SV lens (6:2)
designs. Those contrellers that use smaller bifocal
(0:2) and general-purpose PAL (0:1) designs preferred
the Technica® to their original prescription eye-
glasses. For the more mature presbyopic ATCSs, in-
termediate distance viewing becomes more difficult
with SV lenses, and traditional multifocal lens designs
with higher add powers are required. The study found
that 55.6% of subjects = 44 years of age and requiring
add powers 2 1.25 D preferred the Technica® with its
progressive design. It was anticipated that this per-
centage would be higher. However, for some indi-
viduals, the scanning requirements of an ATCS may
not be compatible with the limitations imposed by the
Technica’s® relatively narrow intermediate viewing
area and the induced distortions of the lens, compared
to SV and other multifocal lens designs.

Even with the visual jimitations of the Technica®,
there is evidence that some controllers felt its benefits
were significant. While ten controllers (76.9%) re-
ported limited field of view when using the Technica®,
two (20%) of these subjects preferred the Technica®
to their current eyeglasses. With the Technica®, eight
controllers (61.5%) complained of distortion, and
two (25.0%) of these preferred the Technica® to their
current eyeglasses. Ir is possible that older ATCSs
accustomed to the wider viewing areas of their current
lens designs, would require a prolonged adaptation
period to rehabilitate their visual scanning skills and
learn to ignore the negative features reported with the
Technica®, namely the limited field of view and
peripheral distortion.

Ivis important to note that a substantial number of
the test subjects (5) felt that vision with their original
lenses contributed to their job stress. Whether this
was due to inadequate refractive corrections or un-
suitable fit of the eye glasses was not determined. The
five controllers who subsequently preferred the
Technica® lenses reported that the lenses decreased
stress, increased efficiency and decreased fatigue, or
had little to no effect on these work-related symptoms.

Technica® was designed for the VDT user and
office employees who work at a desk. When asked if
they found the TechnicaO useful in other situations,
nine ATCSs (69.2%) reported using their TechnicaO
at home while working at the VDT, during casual
reading, and for watching television. A VDT user
normally views a screen equal to 60-80% of their near
add and at a viewing angle 10-20° below straight
ahead gaze. The fact that the average intermediate
working distance of the ATCS test subjects was 88.9
(35") + 2.9 cm, approximately 45% of the wearer’s
total add power, makes it considerably further away
than the typical computer screen, 40 - 76 cm (16" -
30"). Many people find 51 - 66 cm (20" to 26") most
comfortable. A 1989 National Transportation Safety
Board recommendation to the FAA states that for the
ATCSs, “all corrections required to demonstrate 20/
20 vision at all applicable distances should be present
in the same pair of corrective lenses” (). However, an
all-inclusive lens for the mature presbyopic ATCS
that would provide adequate viewing of all compo-
nents of the radar console would be difficult, if not
impossible to design. For the mature presbyope, im-
proved viewing at one distance, or area of the field of
vision, is almost always at the decrement of viewing
another. A prior study on the visual ergonomics of the
sadar console environment revealed that the primary
components of the radar console require the ATCS to
scan over large surface areas, and specialty lenses may
be required for viewing components overhead. It also
found thatan individual’s eye height in relation to the
ATCS radar console environment would be an impor-
tant factor in fitting vision correcting lenses (4).
These factors should be included in any future ergo-
nomic redesigns of the en route radar work station.

The study was compromised by the small number
of participating controllers. Age may have contrib-
uted to this since, for ep route controllers, there is not
only a maximum entry age (i.¢., may not have reached
their 31st birthday prior to initial appointment), but
also a mandatory separation at 56 years of age from
positions requiring direct separation and control of
air traffic (). Other reasons for nor participating may
have been changing work schedules, the limited num-


{EYESTRAIN Subject # 2, 3,7, 8, 13
BLURRED VISION Subject #: 2, 4, 5, 7, 8, 9, 10, 11,12, 13
HEADACHES Subject #: 1, 2, 14, 13
NECK PAIN Subject #. 7, 3,6
BACK PAIN Subject # 1,6
ISORE/SCRATCHY EYES Subject # 2
DISTORTIONS “[Subject #: 7
LIMITED FIELD OF VIEW Subject #: 3, 14
GLARE/REFLECTIONS Subject #2, 7
LIMITED WORKING DISTANCE Subject #: 5, 10, 12

Table 2:

Subjective Complaints
the Work Environment.

with Original Lens Correction in

EYESTRAIN Subject #: 2, 5, 7, 8, 9, 10

BLURRED VISION Subject # 2, 7, 8,9, 1

HEADACHES Subject #: 7

NECK PAIN Subject #._7

BACK PAIN Subject #:

peescnarcty EYES Subject #:

DISTORTIONS Subject #: 1, 2, 5, 7, 8, 9, 12, 13
{LIMITED FIELD OF VIEW Subject #: 2, 3, 5, 6, 7, 8, 9, 10, 12, 13
GLARE/REFLECTIONS Subject #6, 7, 8,S

lenarer WORKING DISTANCE | Subject #3, 7

Table 3:
Environment.

preferred the Technica® lenses reported decreased
work-related stress, increased efficiency and/or de-
creased fatigue with this lens design. These controllers
also reported fewer visual and physical symptoms and
more overall comfort with use of the Technica®.
Similarly, subjects who preferred their current lens
designs were more complimentary of the virtues of
that design in the work environment. At the three

month follow-up, all the ATCS who preferred the

Subjective Complaints with Technica® in the Work

Technica®, retained the use of the Technica® design
while none of the controllers who preferred their
current lenses switched to the Technica® design.

DISCUSSION

The majority of en route ATCSs preferred their
current lens design (61.5%) over the Technica® de-
sign (38.5%) while working at the radar console. In


Progressive Addition Lens

Distant Viewing Zone

Intermediate Viewing Zone

Near Viewing Zone

Aberraticn Zones

Aberration Zones

Distant Viewing Zone

Major Reference Point
(50% of add power)

intermediate Viewing Zone

Near Viewing Zone

Figure 3: Progressive Addition Lens vs. TruVision Technica®



APPENDIX D

Comparative Experience Survey

Name: PL#: Date

4.) Please note any general observations you made when comparing the two lens designs:

2.) Can you identify any situations in which you found one lens or the other superior? If so, which
one, and in what way?

3.) With which lenses did you:

Technica® Previous No Difference
A) Experience less fatigue :
B) Experience fewer visual symptoms
C) Experience fewer physical symptoms
D) Experience fess work related stress
£) Work more efficiently

F) Experience more overail comfort

4) oe all the factors, the statement | most agree with is: (please check one)

1 preter the new the new lenses
+ refer the new lenses
3.) | have no preference, | like both lenses equally
4. H prefer py previous lenses
8 1 strong Hy prefer my previous lenses

.) have difficulty assessing.

5.) Which pair of lenses to you plan to wear at work in the future?
Technica® lenses Previous Both

6.) Did you find the Technica® lenses useful in any other situations? If yes, please explain:

Comments:

DI



ACKNOWLEDGMENTS

The authors would like to acknowledge American Optical Corporation and in particular
Suzanne Nylander, O.D., Director of Professional Relations, for their technical and financial
support of this work. We gratefully acknowledge the outstanding clinical and administrative
support provided by the representatives from Krug Life Sciences, Inc., of Houston, Texas,
including: Mr. Michael Caputo, Keith Manuel, O.D., Robert Gibson, O.D., and Mrs. Donna
Winter-Manuel. We wish to thank Anthony Zeigler, M.D., retired Southwest Regional Flight
Surgeon for his administrative and moral support, and the management and staff of the
Houston Air Route Traffic Control Center in Houston, TX, for their time, patience, and
kindness shared with the research staff during this project.

iit


APPENDIX A

Evaluation of Current Lenses

Subject # Date

Please fee! free to indicate values such as 2.5 or 4.5

How well do your current glasses meet your visual needs at work?

1 2 3 4 5
not at ail poorly satisfactorily well perfectly

What limitations do you experience with these glasses?

What do you like about your current glasses?

Do you fee! that your vision with your current glasses is the same as when you first
received them?

yes no

if no, in what way is your vision different?

How comfortable are you with your present glasses at work?

1 2 3 4 5
very uncomfortable uncomfortable satisfactory comfortable very comfortable

Are you experiencing any specific discomfort with your present glasses?

yes no

Please continue to next page.

Al


APPENDIX B

Subject Information

Date: I Ng.

Subject#: Age:

Job Title:

Hours/week at radar console:
How long working at ATCS: yrs., months

Work reiated visual complaints (eyestrain, blurred vision, etc.):

Physical complaints (headaches, neck or back pain, etc.):

Health history (please circle all conditions that currently apply):

glaucoma cataracts macular degeneration diabetes
hypertension other.

Medications (Please list both prescription and non-prescription that are currently used):

Record Subject’s Work Measurements:
Distance from eyes to center of screen

Distance of eyes from floor when working ai radar screen

Bi


Technical Report Documentation Page

DOT/FAA/AM-96/27

7. Report No. 2. Government Accessio., No.

3. Recipient's Catalog No.

4. Titie and Subtitle

The Use of Task-Specific Lenses by Presbyopic Air Traffic
Controllers at the En Route Radar Console

%. Report Date

December 1996

6. Parforming Organization Code

7. Author(s)

8. Performing Organization Report No.

Van B. Nakagawara, O.D.; Kathryn J. Wood

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

FAA Civil Aeromedical Institute

P.O. Box 25082 11. Contract or Grant No.
Oklahoma City, OK 73125

12. Sponsoring Agency name and Address 73. Type of Report and Period Covered

Office of Aviation Medicine
Federal Aviation Administration
800 Independence Ave., S.W.

Washington, DC 20591 14. Sponsoring Agency Code

15. Supplemental Notes

This work was performed under task AM-A-95-PHY-156.

16. Abstract

Introduction: The configuration of the radar console to control aircraft traffic has similar features to a visual display
terminal (VDT) work station. Task-specific lenses have been found in clinical studies to reduce visual symptoms while
working at the VDT. The American Optical Corporation TruVision Technica®, a task-specific lens design, was
evaluated to see if visual benefits from such a lens could be transferred from the VDT environment to the radar console
work environment.

Methods: Presbyopic Air Traffic Control Specialists (ATCSs) at the Houston Air Route Traffic Control Center were
fitted with two prescription spectacles, using their current and Technica® lens designs, in similar ophthalmic frames.
Each ATCS used both lens designs at the radar console and provided subjective evaluations of their appropriateness in
that environment.

Results: Thirteen (13) subjects (45.6 + 5.9 years of age, range 36-55 years) completed the study. Subjects who used
larger near viewing area (single vision and executive) lens designs generally preferred their current lens design. The
Technica® was preferred by mature presbyopes (add power of 2 1.25 diopters) and those using smaller near viewing
area (FT-25, FT-28 and general progressive addition) lens designs. The primary complaints reported by ATCSs with
the Technica® were peripheral distortion and limited field of view.

Conclusions: Task-specific lens designs are an alternative for presbyopic ATCS who work at a radar console. However,
distortion and limited field of view from the lens may require prolonged adaptation times before such designs are
acceptable to ATCS on the job, especially for those accustomed to lens designs with larger viewing areas.

17. Key Words 78. Distribution Statement
Aviation; Vision; Lenses; Presbyopia; Document is available to the public through the
Occupational Health National Technical Information Service,
Springfield, Virginia 22161
19. Security Classif. (of this report) 20, Security Classif. (oF this pagel 21. No. of Pages 22. Price
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ber of presbyopic ATCSs who work at the console
(many senior controllers were in supervisory/manage-
ment positions and could not meet the required
number of hours working at the radar console), con-
cern about reporting additional medical information
to FAA, and satisfaction with their current vision
correction. The requirement that the participants
have a current refractive prescription further limited
our subject pool, since many individuals do not have
routine eye examinations. Even when this condition
was met, some current prescriptions were problem-
atic, since several were reported questionable by the
contractual vision specialists for the intermediate dis-
tance for which they were being used.

A study with quantitative test results of controller
performance would have been preferred. However, a
performance-based test was not an option in this
study, since we could not interrupt the ATCSs while
they were controlling air traffic. The use of subjective
responses to survey questions, which are not easily
quantifiable and are sometimes difficult to interpret,
was the most practical method of evaluating the us-
ability and feasibility of these ophthalmic lenses on
the job.

In conclusion, for en route ATCS working at the
radar console, our test results suggest that a lens type
with a wider field of view (SV or Executive) is gener-
ally preferable to a Technica® lens design. However,
Technica® may be preferable for those ATCSs using
smaller multifocal lens designs, such as FT-28, FT-35
or general-purpose PALs. Although the Technica®
provides a relative wide intermediate and near vision
area, it may not be wide enough for the visual scan-
ning required for work at the radar console, resulting
in complaints of distortion and limited field of view.
Itis possible that the TechnicaO may be more accept-
able in other air traffic activities, such as automated
flight service stations, which use more traditional
VDT equipment. Although nor a panacea for ali
presbyopic controllers who need corrected vision for
near and intermediate distances, the Technica® is a
viable option for eyecare practitioners correcting
ATCSs with occupational vision problems. The five
controllers who preferred the Technica® lenses in
this study reported decreased work-related stress, in-
creased efficiency, and/or decreased fatigue. With a

longer period of adaptation or with improvements in
refractive prescriptions, it is possible that all of our
subjects could have adapted to the TechnicaO. Fur-
ther study on the corrective needs of presbyopic ATCSs
is needed as current demographics of the ATCS popu-
lation forecast a substantial increase in early and
mature presbyopic controllers in the next decade,
many of whem will be full performance level ATCSs
working at the radar console (4).

REFERENCES

1 Nolan MS. Fundamentals of Air Traffic Control,
2nd Ed. Belmont CA: Wadsworth Publishing
Company, 1994.

2 Schroder DJ, Broach D, Young WC. Contribu-
tion of personality to the prediction of success in
initial air traffic contro} specialist training. Wash-
ington DC: Department of Transportation/Fed-
eral Aviation Administration; 1993; FAA Report
No. DOT/FAA/AM-93/4. Available from: Na-
tional Tect *~| Information Service, Springfield,
VA 22161.

3. Endsly MR, Rogers MD. Situation awareness in-
formation requirements of en route air traffic
control. Washington DC: Department of Trans-
portation/Federal Aviation Administration; 1994;
FAA Report No. DOT/FAA/AM-94/27. Avail-
able from: National Technical Information Ser-
vice, Springfield, VA 22161.

4  WNakagawara VB, Coffey JD, Montgomery RW.
Ophthalinic requirements and considerations for
the en route air traffic control specialist: an ergo-
nomic analysis of the visual work environrent.
Washington, DC: Departmentof Transportation!
Federal Aviation Administration; 1996, FAA Re-
port No. DOT/FAA-AM/96/12. Available from:
National Technical Information Service, Spring-
field, VA 22161.

5 Milder B, Rubin ML. Progressive power lenses.
Survey of Ophthalmology. Nov-Dec 1987;
32(3):189-8.

6 Nylander SH. Some considerations in progressive
lens design. Eye Quest Magazine. Sep-Oct 1992;
2(5):77-9.


Appendix A (cont.)

Subject #:

If yes, please check off the category and severity of symptoms:

1) eyestrain severity: mild moderate. severe
2) blurred vision severity: mild moderate severe
3) headaches severity: mild moderate severe
4) neckpain severity: mild moderate severe
5) back pain severity: mild moderate severe
6) other severity: mild moderate severe

Do you feel that your vision with your glasses contributes to job related stress?

1 2 3
not at all to some degree significantly

Please explain:

Do you have any observations about your vision or your glasses that have not been
touched on in these questions? If so, please note below: