1. UZ Antwerp Effect of compensatory viewing strategies on practical fitness to drive in subjects with visual field defects caused by ocular pathology. Tanja Coeckelbergh W.H. Brouwer, F.W. Cornelissen, A.C. Kooijman University of Groningen, The Netherlands current address: University Hospital Antwerp, Belgium

2. UZ Antwerp Bioptic telescopes are intended for detailed vision (street names, signs, etc.) not for regular driving  are subjects with decreased visual acuity able to drive safely?

3. UZ Antwerp Subjects central VFD (n=24) peripheral VFD (n=36) central and peripheral (n=7) mild VFD (n=33) vision parameters visual acuity (logMAR)0.64 (0.03)0.14 (0.02)0.72 (0.08)0.11 (0.02) horizontal field *(°)142 (13)84 (35)91 (35)141 (13) sample characteristics male : female16:829:74:314:19 age65 (13)60 (12)63 (15)67 (9) driving license (# years)38 (11)37 (10)39 (17)38 (8) * Goldmann III4 isopter

4. UZ Antwerp On-road driving test own car own neighbourhood official driving examiner (CBR) 1 hour score: viewing behaviour, lateral position, anticipation, changing lanes, turning left, … pass/fail score www.cbr.nl

5. UZ Antwerp On-road driving test central VFDmild VFD passed:6 (25%)21 (64%) unfit to drive:5 (21%)0 (0%) not yet fit to drive: 13 (54%)12 (36%) fit to drive, limited:6 (25%)9 (27%) fit to drive: 0 (0%)12 (36%)

6. UZ Antwerp Percentage of subjects passing TRIP items: central VFDmild VFD lateral position66.784.8 lane choice70.866.7 car following95.897.0 speed66.769.4 viewing behaviour33.339.4 detection of traffic signs58.3**93.9 overtaking45.872.7 mechanical operations75.084.8 anticipatory behaviour37.563.6 communication45.878.8 turning left37.551.5 merging into another lane37.557.6

7. UZ Antwerp Driving simulator

8. UZ Antwerp Driving simulator: subjects

9. UZ Antwerp Driving simulator: results central VFDmild VFD speed (km/h)67(9)**74(9) lateral position SD (m)n.s. thw-averagen.s. thw-minimumn.s. ttc-minimum (log)0.61 (.16)**0.70 (.15) breaking dtin.s. release accelerator dtin.s. accident (% drivers)n.s.

10. UZ Antwerp

11. -0.2 -0.1 0 0.1 0.2 0.3 0.4 constantvariable driving speed of lead car log THWmin central VFD peripheral VFD mild VFD

12. UZ Antwerp Compensatory behaviour viewing behaviour – pass/fail score central VFD: no relationship speed – pass/fail score: central VFD: drive more slowly => pass

13. UZ Antwerp Conclusions before training On-road driving test: detection of traffic signs was (too) late Driving simulator: decreased driving speed (compensation) shorter following distance lateral position independent of road curvature bioptics!bioptics?

14. UZ Antwerp Training aim: teach compensatory viewing strategies laboratory trainingcomputer based tasks mobility trainingwhile walking or cycling motor traffic trainingwhile driving a car

15. UZ Antwerp AFOV 60 degrees 24 degrees -15 -10 -5 0 5 10 15 -30-20-100102030 0 1 2 3 4 threshold presentation time (s) Dependent variables: mean threshold presentation time variation (PDM)

16. UZ Antwerp Subjects motor laboratorymobilitytraffic central VFD557 peripheral VFD687 centr+periph VFD221 mild VFD314

17. UZ Antwerp AFOV 0 0.1 0.2 0.3 0.4 pre1 pre2 post1 post2 assessment log threshold presentation time 0 20 40 60 80 100 PDM thresh. present. time PDM

18. UZ Antwerp Driving simulator 0 10 20 30 40 50 60 70 pre1 pre2 post1 post2 session number of head movements 0 5 10 15 20 25 30 distance to intersection (m) number dti

19. UZ Antwerp On-road driving test 0 0.5 1 1.5 2 2.5 pre1 pre2 post1 post2 session viewing behaviour (0-3) laboratory mobility motor traffic

20. UZ Antwerp On-road driving test 0 10 20 30 40 50 60 functionmobility motor traffic training % pass pre2 post1 post2

21. UZ Antwerp Positive training results: compensatory viewing behaviour (AFOV) viewing behaviour while driving practical fitness to drive (pass/fail score) best results: motor traffic training Conclusions after training

22. UZ Antwerp Central VFD before training: 6/24 passed on-road driving test training: 17/24 (14 failed, 3 passed) after training: 8/17 passed on-road driving test (5 had failed before training)

23. UZ Antwerp Conclusion Are subjects with decreased visual acuity due to a central visual field defect able to drive safely? Yes, 11/24 (46%) passed on-road driving test. Might bioptic telescopes be helpful to these subjects? Yes, to improve ‘detection of traffic signs’ and ‘following distance’.