1. Priya Ramamoorthy BSOptom, MS
Computer Display Placement Preference In Progressive Addition Lens (PAL) Wearers
Priya Ramamoorthy BSOptom, MS
James Sheedy OD, PhD
Carolyn Sommerich PhD

2. Current Recommendations
Placement slightly lower than horizontal
HFES (computer workstations)
Monitor location 15º–20º below horizontal eye level
Research reports on younger subjects
Preference for placement < eye level
Gaze angle preference ranging from -3º to -22º
Research on PAL wearers
Musculoskeletal & visual fatigue with multifocal wear
↑ muscle load in PAL wearers (Aaras & Horgen ’89, ’95, ‘02)
Preference for lower placement (Kumar ‘94)

3. The Case of the Presbyope
What is Presbyopia?
Spectacle correction for presbyopia
Progressive Addition Lenses (PALs), Bifocals
The presbyope challenged at his computer workstation
Restriction of PAL Optics
Downgaze demand ~ 20º- 35º for clear near vision through PALs
Excessive strain upon the neck/upper torso

4. Our Study
Aim
To determine computer display placement preference in PAL wearers
Study the effect of task, seat reclination and touch typing ability of subjects

5. Methods 30 subjects Test conditions Outcome Measures
3 Tasks - Reading, Typing, Editing
3 Seat Reclinations - 100º, 110º, User defined (UD)
Neutral posture assessment
Outcome Measures
Preferred locations of the monitor and keyboard
Subjects’ postures
Motion Monitor™, an electromagnetic motion tracker

6. Study Set-Up

7. Posture Evaluation

8. Results – Preferred Monitor Placement
100º
110º UD
*Previous reports for younger observers - - 3º to - 22º at 57 – 79 cm
Current Placement – 51 – 57 cm
PAL Demand

9. Monitor Tilt Range between – 15.6º and – 21º
Gaze w.r.t. horizontal - 16˚ to - 22˚
Monitor tilt is maintained perpendicular to the subjects’ gaze

10. The Posture – Gaze Respective to Horizontal
Averages range from ~ 21º to 25º
Neutral value: º
Previous reports: 8.9º to 19º
PAL wearers’ gaze ~ 9º higher
Non-touch typists vs. the rest

11. Head and Neck Behavior Average head angle range: 159.9º to 163.6º
Neutral:
Previous studies: 138.1º to 151º
> 10º greater than non-PAL wearers

12. Neck Flexion Forward neck flexion range: ~44º to 52º
Neutral: 47.19º
Other studies: 36.6º to 50º

13. Some Inferences.. The posture of PAL wearers Comparison with neutral
PAL wearers’ gaze higher
Head angle greater than non-PAL wearers
Increased forward neck flexion
Comparison with neutral
Case of the non-touch typists

14. Conclusions PAL wearers prefer a slightly lower monitor placement
Stressful craning posture despite being presented with highly adjustable workstation
Risk for MS discomfort in the head and neck regions
Non-touch typists are at a significant disadvantage
SOLUTIONS:
Better workstations/ occupational spectacles
Simpler measures
User education

15. Acknowledgement