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A
presentation, Driving With Low Vision
The
following information is excerpted from a presentation give by Dr Dennis
Kelleher at the 1996 NOAH Conference in San Jose, California. Dr.
Kelleher has written many papers on BiOptic Driving.
Click
here for a bibliography of his papers. [25.3 Kb PDF format]
A comprehensive bibliography on the subject is available by
clicking
here.
Dennis
was the first person licensed to drive in California using a BiOptic in March
1971. Since then he has driven in all types of conditions compiling a better
than average driving record. He received his Doctorate in Education in 1972 from
UC Berkeley. He has taught many low vision courses at the college level
including the UC School of Optometry and has written over 17 articles published
in professional journals on various topics in low vision. He served on the
California DMV drivers license advisory board from 1975 to 1983.
Visual
Factors in Driving Safety:
-
Static
Visual Acuity (screening standard 20/40 in most states)
-
Dynamic
Visual Acuity
-
Visual
Fields (130 degrees) & effects of speed blur
-
Color
Perception
-
Depth
Perception, monocular vs. binocular
-
Contrast
Sensitivity, Glare Recovery & Luminance
Research
has established that normally sighted drivers do not resolve details on a
continuous basis at 20/20 acuity while driving, but as a response to low
resolution stimuli. The common 20/40 screening standard is not the same as a
rejection criteria because DMV vision tests are based on what is reasonable, not
on what has been proven absolutely necessary for safe operation of a motor
vehicle. The greater the deviation, the more the safety margin is
reduced. Not all persons with low vision are able to drive. Driving is certainly
not for everyone, even those low vision persons who meet the above criteria and
may be able to drive, but don't have a desire to do so. DRIVING WITH LOW
VISION, WITH OR WITHOUT BIOPTICS IS A VERY PERSONAL DECISION THAT SHOULD BE MADE
COLLABORATIVELY BY THE INDIVIDUAL, THE EYE SPECIALIST AND THE LICENSING AGENCY.
Non
Visual Factors in Driving Safety
Research
has established that drivers who are more likely to be involved in an accident
are those who are:
-
impulsive,
emotionally unstable, overly aggressive & angry
-
inattentive
and have slow reaction time
-
substance
abusers & risk takers
-
Inexperienced
or new drivers
-
teenagers
and those over age 75
-
health
impaired with respect to mobility, hearing or vision
1994
California DMV BiOptic Study
Persons
with any medical disorders tend to have more traffic accidents than those
without them, but also have fewer citations. A study by California DMV in 1994
was conducted on 669 BiOptic drivers. The BiOptic group was composed of 71%
males with an average age of 46. In comparison to the control group, the BiOptic
group's accident rate was 1.5 times higher than the control group, but the
citation rate was one third lower than the control group. These findings are
consistent with the BiOptic study done by the California DMV in 1983. Other sub
groups with medical disorders such as persons with hearing loss, seizure
disorders and orthopedic impairments had an accident rates up to 2 times higher
than the BiOptic driver group. The study concluded that the BiOptic group did
not pose an unacceptable high risk and license restrictions for BiOptic drivers
are appropriate. Considered restrictions included:
-
geographic
area
-
specific
hours of the day
-
specific
familiar roads & routes
-
specific
vehicle using special equipment or devices
-
more
frequent and rigorous testing by the licensing agency
General
Prerequisites in California for licensing using a BiOptic
-
Visual
fields of approximately 130 degrees
-
A
stable vision condition preferably of long duration absent of other problems
-
Adequate
(20/40) central acuity through the BiOptic and no less than 20/200 through
the standard carrier lens
-
Ability
to differentiate color
-
Ability
to track objects through eye movements, head and neck coordination
-
Need
to drive for employment or independence
DRIVING
IS A PRIVILEGE, NOT A RIGHT
Common
Concerns regarding the use of the BiOptic
-
Small
visual field through the BiOptic telescope
-
Ring
scotoma causing a hazardous blind spot
-
Vibration
and speed blur
-
Telescopic
parallax and depth perception
-
Using
the BiOptic with mirrors
-
Critical
adjustment of the BiOptic frame and angle of the lens
Using
the BiOptic telescope
-
BiOptics
are used as a spotting device, intermittently during driving, never
constantly.
-
The
amount one spots through the BiOptic varies depending on the type of
driving.
-
Generally
the faster one is going, the more often the BiOptic will be used.
-
A
majority of the driving task will be done using the vision through the
carrier lens.
-
Maximizing
eye movement instead of head movement will decrease response time.
BiOptic
-
Rapidly
locate stationary objects while you are still
-
Rapidly
locate moving objects while you are still
-
Rapidly
locate moving objects while you are moving (preferably as a passenger in a
car)
-
Develop
accurate visual perception skills to evaluate the environment rapidly
Defensive
Driving Habits
-
Keep
your eyes moving and be alert
-
See
the whole picture and anticipate what they other driver will do in advance
-
Be
sure you are seen
-
Follow
at a safe distance (four second rule)
-
Be
sure you have an escape route as a last resort
-
Be
prepared by knowing where you are going in advance
-
Use
other aids as necessary (hats, visors, tinted lenses, magnifiers etc.)
Driver
Skills
-
Vehicle
speed control, shifting and braking
-
Depth
and spatial perception
-
Steering
-
Use
of Mirrors
-
Backing
up and parking
-
Knowledge
of rules of the road and courtesy
-
Compensation
for low vision (practice announcing what you must react to)
To
see a detailed MS PowerPoint presentation given by Dr. Dennis Kelleher on factors
concerning driving with BiOptic Telescopic Systems, click
here. (687 Kb)
-
Dennis Kelleher, Ed.D
Special
Education Consultant, Office of the Director, Special Education Division
California Department of Education 428 J Street, Suite 550 Sacramento, CA 95814
916-327-0842 Voice 916-445-4550 FAX
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