Presentation Transcript

1. BIOPTIC DRIVING: APPLICATION & OUTCOMES TO LOW VISION DRIVING

   Chuck Huss, C.O.M.S. Consultant - Bioptic Driving chuck.P.huss@wv.gov (304) 760-7149
2. Bioptic driving
3. Bioptic driver training
4. Objectives of presentation Educate - basics re bioptic driving Educate - common misconceptions Provide – update ofbioptic driving activities, USA & abroad
5. Why the confusion re bioptic driving?(Part II)
6. Common misconceptions Optics of device User’s ability to see Basic use of device Use in familiar areas
7. Misconception No. 1 The optical limitations far outweigh the optical advantages of bioptic lens systems; making such devices unsafe for use during driving.
8. Optical limitations Nearness illusion - Objects or forms appear closer - Depends on level of magnification - In reality, object/form is X times farther away - Jack in-the-box effect
9. “Jack in the box” effect Other road users that suddenly and unexpectedly move into the magnified or non-magnified field of view or path of travel
10. Developing “Jack in the box”
11. “Jack in the box” effect
12. Concern of “Jack in the Box” Oncoming, lateral, same direction Sudden braking, rear-end accidents Rationale for short fixations
13. Optical limitations (cont’d) Restricted magnified field of view - Dependent on (X) Power, type and size of telescopic units - Dependent on “vertex distance”
14. Sampling: telescopic fields of view ManufacturerField of view (degrees) DVI - 2.2X BIO I, BIO II Galilean .……………………. 12, 11 - 3.0X WA BIO I; 3X BIO I, 4X BIO I Galilean .... 11, 8, 6 Ocutech - 1.7X, 2.2X Sight Scope Flip ..………………….. 26, 18 - 3.0X Mini …………………………………………. 15 - 4X VES –K ……………………………………….. 12 Conforma - 4X ½ BITA ....….………………………………….. 8.5
15. Vertex distance Linear distance or space between center of cornea and center of carrier lens, or center of ocular lens of telescopic unit Bioptics are not “horse blinders”
16. Optical limitations (cont’d) Ring scotoma– part of the normal visual scene invisible to the user Created by the enlarged retinal image produced by telescope (overlaps part of the normal visual image)
17. What photo of “ring scotoma” does not tell you? Scotoma exists for a few milliseconds (intermittent vs. continuous viewing) Extent of non-magnified field Impact of 1 vs. 2 telescopes *Source: Randy Jose, O.D., 2011 SWOMA Conference
18. Normal visual field Visual field of one eye overlaps visual field of other eye Central macular vision that is often impaired in bioptic drivers accounts for a small amount of field *Source: Dr. Laura S. Miller, O.D. (ww.nwhillseyecare.com)
19. Optical limitations (cont’d) Apparent movement of visual scene (objects or forms) in opposite direction to head movement - Consistent with all types of devices that magnify or enlarge - Rationale for vertical spotting only
20. Apparent movement of object or form opposite to head movement
21. Apparent movement of object or form opposite to head movement
22. Apparent movement of object or form opposite to head movement
23. Optical advantage Increases “margin of safety” - the time or distance needed to detect and identify a critical object or condition; then predict, decide and execute an appropriate driving maneuver.
24. Optical advantage Allows bioptic user to detect and identify detail, color and activity of distant objects or forms at farther distances
25. Approach magnification Driving slower and closer to critical object(s) or critical situations before making a decision of what to do or not do
26. Misconception No. 2 Low vision drivers depend upon the telescopic portion of their bioptic lens system to see.
27. In reality Low vision drivers can see in the distance, but not distinctly (carrier lens vision). Bioptic lens users can be taught to use functional visual acuity measures (with and without telescopic magnification).
28. Functional visual acuity measures Awareness acuity – “I notice something ahead but can’t identify what it is” (gross difference between foreground and background) Identification acuity – “It is beginning to look like a red vehicle” (as driver gets closer to object) Sure acuity – “I definitely recognize it as a red car” (at furthest yet optimal viewing distance)
29. Awareness acuity
30. Awareness acuity
31. Identification acuity
32. Sure acuity
33. Misconception No. 3 A low vision driver, who is dipping down into the telescopic portion of their bioptic lens system every few seconds or so, is illustrating safe driving practices.
34. In reality Driving is a dynamic task that requires far greater input from the peripheral or side portion of one’s field of view. “If you can’t drive without it, you can’t drive with it”.
35. Why use the telescopic unit? At “critical periods” to increase one’s margin of safety “Margin of safety”defined as - the time or distance needed to detect and react to a critical object or situation
36. Unexpected road closure!
37. Misconception No. 4 Low vision drivers need not use bioptics while driving in familiar driving environments.
38. In reality Drivers have no control over anything that takes place outside of their vehicles - First in line at traffic light (multi-lane crossroad) - Flagger @ road repaving site, water line breaks, tree trimming - First responder(s) at scene of motor vehicle accident
39. First in line at a traffic light
40. Traffic light with left turn arrow
41. Flagger - work site
42. Flagger - work site
43. Motor vehicle accident scene