1. Bi0ptic Telescopes The patient, the decisions, and the training
Ian L Bailey, OD, DSc, FAAO
School of Optometry
University of California, Berkeley. CA

2. Basic Vision Functions and Driving
Visual acuity reading signs, seeing detail
Contrast sensitivity seeing larger objects, borders, textures
Visual fields seeing things to the side
Color vision ability to see traffic signals, warning lights
Glare veiling haze from headlights or bright light
Adaptation (light/dark) adjusting to changes in light level
Light sensitivity ability to see in dim conditions

3. Should visually impaired people be allowed to drive? The Dilemma
For denial to be justified
Evidence of individual incompetence
Evidence (associations) of highly elevated risk
Strong prima facie argument for highly elevated risk
Caution when considering statistical evidence
Associations describe trends - they are not rules
Higher crash rates for a given group is insufficient,
by itself, to disqualify all members of that group

4. Should visually impaired people be allowed to drive?
Licensing Authorities (DMV’s) have the responsibility
to test driving abilities, to allow or deny licensure,
and to impose any restrictions
They may consider Special driving tests
Past driving experience
Anticipated driving needs
Causative disorder
Other health issues (sensory, motor, cognitive)
They may impose Closer monitoring of driving record
More frequent vision and driving tests
Restrictions on routes, time of day, etc.
Restricted vehicle categories, speed
They may require BiOptic telescopes

5. What is the use of BiOptic Telescopes?
BiOptic telescopes are
Head mounted telescopes Typically magnification (for driving) = 2x to 4x
Arranged to allow easy interchange from viewing with and without the telescope
BiOptic telescopes magnify
Enable distant details to been seen to be seen more easily.
Advantages for driving
Signs, signals and other features with more small details
can be seen at a longer distance than they otherwise could be
Disadvantages
Ring scotoma can reduce field of view
Brightness may be reduced
Head and/or eye movements are required to interchange

6. Vision impairment and Nystagmus
Congential Nystagmus Reduced visual acuity
Normal contrast sensitivity
Normal visual fields Astigmatism
Albinism Reduced visual acuity
Normal visual fields Astigmatism, High refractive error (+)
Some sensitivity to light
Achromatopsia Reduced visual acuity
Reduced contrast sensitivity (somewhat)
Normal visual fields
Poor color discrimination
Photophobia
Astigmatism, High myopia in some (Blue cone)

7. Is seeing fine detail important to driving?
Yes!
Reading signs
(freeway signs, street signs, warnings, parking, house numbers, building signs)
Traffic signs size and location usually designed on assumptions that
drivers will have a visual acuity of 20/40 (6/ 12 or 0.5)
But!
Reading signs, or attending to fine details
required for short-term and infrequent driving tasks
Especially in familiar areas, and other situations where need to read signs is minimal

8. BiOptic telescopes only engaged intermittently
BiOptic telescopes allow fine details to be seen from a longer distance
A driver who obtains 20/40 or better through telescope,
should be able to read roadway signs, etc., from the intended distance
BiOptic telescopes only engaged intermittently
for short periods when attending to signs (or other fine detail)
BUT
Potential danger when looking through telescope
because part of visual field is occluded (RING SCOTOMA)

9. Illustration of RING SCOTOMA with 3x telescope
For a 3x telescope
Occluded area is 8x larger than the area being magnified

10. Projecting a telescope ring scotoma

11. Ring scotoma could be hazardous
When viewing through telescope. There must be
a substantial para-central field loss from the ring scotoma,
IF -- the second eye is occluded
OR -- if the second eye is functionally blind
OR -- if there is a binocular telescope system
BUT
When viewing through telescope, there is no field loss
Provided -- second eye does not have a telescope
remains open
can readily detect large peripheral objects
does not have profound suppression

12. Some visual criteria for selecting patients for BiOptic Telescopes for driving
Best corrected Visual Acuity - 20/160 to 20/50 range (6/48 to 6/15)
Telescope V A (M= 4x or less) /40 to 20/32 range (6/12 to 6/9.5)
Should not have more than a 3x (0.5 log units) reduction in CS
Should not have significant field defects
Telescope before one eye only (better reading eye)
Second eye should have VA of 20/400 or better (6/120)
Second eye should not have profound suppression

13. Before prescribing Optometric consideration of visual abilities
Hard numbers on Visual acuity
Contrast sensitivity Visual fields
Evaluate as needed Color vision Glare Adaptation (light/dark)
Light sensitivity
Consider Motor and mental agility
Reaction time
Vision in clutter
Divided attention

14. Put your first name on this paper if you will help tomorrow
Some variations on usual more common tests Visual Acuity Reading efficiency for words and sentences
10 M
8.0
6.3
5.0
2.5
2.0
1.6
1.25
1.0
0.8
0.63
0.5
0.4
0.32
0.25
0.2
Word Reading
10 words each size
Grade 3 word lists
Sentences
60 characters
MNRead
Put your first name on this paper
if you will help tomorrow
Many people came to help us
clean the place after the party

15. Variable luminance backgrounds
Some variations on usual more common tests Visual Fields Effect of illumination
Variable luminance backgrounds
EITHER
Plot fields OR
Ask about letters visible on chart
at different luminances
RP, ARM etc
fields change with luminance

16. Number search Flashing squares
Some variations on usual more common tests Contrast Sensitivity Response Efficiency Tests
Number search Flashing squares
Output display Less than 2 mins per test
Response time measures at 24 contrasts
vs Log CS

17. Some variations on usual more common tests Useful Field of View (UFOV)
Test patient’s ability to respond to peripheral stimuli
Delayed reaction times for peripheral visual stimuli
Failure to see brief, peripheral visual stimuli
(i.e., reduced measured visual field)
When there is Divided visual attention
Visual clutter
Multi-tasking

18. Before prescribing Ensure good skill using telescopes
Hand held telescope - magnification equal to, or stronger, than planned bioptic
Achieve 20/40 with telescope
Efficient spot viewing - both indoors and outdoors
stationary observer - stationary object of regard
stationary observer - moving object of regard
moving observer stationary object of regard
moving observer moving object of regard
Real world location and viewing of targets in visual clutter
first locate the target object, and then engage telescope

19. Before prescribing Advising the patient
Advise patients about their visual disabilities and functional relevance
Bioptic telescope does not ensure ability to pass driving test
Bioptic telescopes do not restore vision to normal
Even with bioptic telescopes, they remain at a visual disadvantage
Need to drive with extra caution
Should have companion drive when possible
Need practice in viewing with bioptic telescope system
Need supervised training using bioptic telescope for driving
If no driving experience, likely to need more instruction than usual from
a professional driving instructor
The DMV makes the final decisions

20. Prescribing BiOptic Telescopes
Select telescope Magnification
Design (Designs for Vision, Ocutech)
Galilean, smaller, light weight, small field
Keplerian, longer, heavier, larger field
Focus fixed, adjustable, auto
Exit Pupil smaller or larger than pupil
Select frame Suitable for telescope mounting
Sturdy and comfortable
Adjustable to vary height, lateral position and angle
Determine lens powers for telescope and carrier lens
Select characteristics of carrier lens (SV, bifocal, tint)

21. Prescribing Positioning & Angling BiOptic Telescopes

22. Training: Using a BiOptic Telescope
Rehabilitation Staff
Five to fifteen lessons of 30 minutes.
Home practice after each lesson Begin practice indoors with flash cards,
Practice outdoors while walking (include traffic signs)
Practice while a passenger in a car
residential, business and freeways
(locate signs, signals, landmarks and then engage telescope)
WHEN patient is proficient with telescope while a passenger
THEN we issue DMV report form, patient applies for permit
AND patient begins training with professional driving instructor

23. Training Test Cards for bioptic telescope evaluations

24. Dealing with the Department of Motor Vehicles
Appointment with a “Driver Safety Referee”
Present vision report that includes information
VA with and without telescope
Fields, contrast sensitivity
Causative eye disease or disorder, stability and prognosis
May be considered a learner’s permit
THEN the patient takes the written test
THEN driving permit may be issued
LATER, patient takes drive test

25. Department of Motor Vehicles Driving test
Driving test appointment with a “Driver Safety Referee”
Driving test
Longer course than usual
Exposure to more visually-demanding driving tasks
Night time drive test may be requested
if patient wants to remove “no night driving” restriction

26. Department of Motor Vehicles Issue of a Driving License
Unrestricted or Restricted License??
Special considerations Driving skill tests Causal disease
Driving experience Visual abilities
Driving record Extent of vision loss
Driving need Prognosis, stability
Anticipated driving Variability of vision Sensory motor disabilities Other visual disabilities
Special constraints
Monitor Accidents Violations
Increase frequency Renewal Vision reports
Driving tests
Restrict Time of day Visibility conditions Routes Purpose
Distance from home Vehicle category
Require BiOptic Telescope Special mirrors

27. Some Conclusions Visual acuity tasks much less important
than visual field and contrast sensitivity tasks
BiOptic Telescopes enable seeing of finer detail,
when needed
Visually impaired drivers should be given opportunity
to demonstrate ability to drive safely
It can be reasonable to specify definite limits
OPINIONS :New California limit -better than 20/200 (6/60) -is acceptable
No driving with hemianopia is reasonable

28. Thank you!

29. For Europe POLICIES TO DEMAND
BiOptic telescope is a corrective lens system
Telescope must allow visual acuity of 6/12 (20/40 or 0.5)
Telescope must be before one eye only
BiOptics are to be used with two eyes open
so, relevant visual field test is with both eyes open
COMPROMISES TO ACCEPT OR CONCEDE 
Vision report every 5 years (at least)
Maximum mag = 4x, or without TS, VA > 6/48 (20/160 or 0.125)
Driving should be conditional on wearing telescope
Initial license should be for daytime use only
Night driving cannot be considered until 3 years experience