Many people feel insecure, and even stressed when driving, especially in difficult light and weather conditions, such as rain, twilight or night.1 On average, 83% of spectacle lens wearers drive, and of those, 72% are interested in an everyday lens solution specialised for driving.1
Zeiss DriveSafe lenses have been developed to address the three most common issues experienced by drivers who wear single vision and progressive addition lenses;
• Poor visibility in low light conditions
• Glare from oncoming cars
• Difficulty switching focus between the road, dashboard and mirrors
Zeiss Luminance Design Technology
A disproportionate number of fatal road accidents occur after dark2,3 and low luminance plays a major role in road traffic injuries.2 In low light, or mesopic conditions, visual acuity, contrast sensitivity and depth perception are reduced.2 Additionally, off-axis aberrations of single vision and progressive addition lenses interact with the enlarged mesopic pupil size to diminish retinal image quality further.
Traditional spectacle lens designs consider discrete light rays to determine the refractive distribution of a lens, whereas the patented Zeiss Luminance Design Technology process considers the entire bundle of rays passing through the mesopic pupil, and also overlaps the bundles to simulate the moving eye (Figure 1A). As a result, Zeiss DriveSafe single vision and progressive addition lenses have a smoothened refractive profile (Figure 1B) that improves contrast and acuity and reduces distortion and swim effects as the eye moves.
[CaptionComponent="2328"]Zeiss DuraVision Drive Safe Coating
While driving, the visual system must adapt quickly to different light levels. High luminance in the visual field, for example headlights from an oncoming vehicle at night, causes discomfort glare. Re-adaptation to lower light levels following glare exposure takes time, and during the recovery period visual performance is reduced. Recovery time increases as the exposure time to glare increases,4 and also depends on age.5
Zeiss consulted with automotive lighting experts, L-LAB, to investigate the effect modern headlights have on glare perceived by drivers. Discomfort glare is highest at short wavelengths of light (blue spectrum),6 which are emitted by Xenon/HID and LED vehicle headlights (Figure 2).
Zeiss DuraVision DriveSafe coating has been optimised to attenuate Xenon/HID and LED vehicle headlight glare by partially reflecting blue light (below 460nm; Figure 3). It enhances visual contrast and provides up to a 64% reduction in perceived glare compared to premium Zeiss MAR coatings.(7) As part of the Zeiss DuraVision coating family, the Zeiss DuraVision DriveSafe coating also provides anti-reflective, anti-static, hydrophobic, oleophobic and scratch-resistant properties.
[CaptionComponent="2329"]Zeiss DriveSafe Progressive Addition Lens Design
Frequent eye and head movements are required to switch fixation between the road ahead, peripheral field, mirrors and instrument panel.8 Progressive addition lens wearers exhibit longer eye and head movement path lengths, and a greater number of saccades when compared with single vision lens wearers, which may negatively affect some aspects of driving performance.9
Collaborative research with the Research Institute of Automotive Engineering and Vehicle Engines, Stuttgart, utilising a real-world driving course and an advanced full-motion driving simulator revealed drivers focus on the road ahead for 97% of the time, look at the dashboard for 2% of the time and use dynamic vision, switching focus between mirrors, for 1% of the time.10 Progressive addition lens wearers also tend to hold their heads more upright than single vision lens wearers when driving.
[CaptionComponent="2330"]Zeiss DriveSafe progressive addition lens design optimises the vision zones to provide extra width for distance vision to facilitate fast and accurate localisation of the mirrors. The intermediate zone is also expanded in all directions, including upwards, to enable easier switching between dashboard instruments and other driving tasks (Figure 4) and a more comfortable head posture.
The everyday lens solution for safer driving
Extensive wearer trials revealed 97% of wearers were very satisfied with Zeiss DriveSafe lenses when driving and 94% when doing everyday tasks.11 Zeiss DriveSafe lenses represent a new single vision and progressive addition lens category, providing an everyday lens solution that has been specifically designed to enhance visual performance while driving.
[CaptionComponent="2331"]Dispensing information
Zeiss DriveSafe lenses are available with these parameters:
• Power: -20 to +16D*
• Cylinder: 6D*
• Add: 0.75 to 4.00*
• Corridor length: Variable (FrameFit value 0 - 6)
• Minimum fitting heights: 14mm
* subject to refractive index and coating
References
1 Zeiss data on file. Market research study with ECPs and consumers with 480 subjects. 2013
2 Plainis S, Murray IJ, Pallikaris IG. Road traffic casualties: understanding the night-time death toll. Injury Prevention. 2006;12(2):125-128
3 Ward H, Shepherd N, Robertson S, Thomas M. Night-time Accidents – A Scoping Study. Report to the AA Motoring Trust and Rees Jeffreys Road Fund. Centre for Transport Studies. University College London, UK. 2005:1-63
4 Irikura T, Toyofuku Y, Aoki Y. Recovery time of visual acuity after exposure to a glare source. Lighting Research & Technology. 1999;31(2):57-61
5 Schieber F. Age & glare recovery time for low-contrast stimuli. In Proceedings of the Human Factors & Ergonomics Society Annual Meeting. 1994:38(9):496-499
6 Flannagan MJ, Sivak M, Traube EC. (1994). Discomfort glare & brightness as functions of wavelength. University of Michigan, USA. 1994:1-19
7 Zeiss data on file. DuraVision DriveSafe research study with 50 subjects. 2014
8 Rahimi M, Briggs RP, Thom DR. A field evaluation of driver eye and head movement strategies toward environmental targets and distractors. Applied Ergonomics. 1990;21(4):267-274
9 Chu BS, Wood JM, Collins MJ. Influence of presbyopic corrections on driving-related eye and head movements. Optometry and Vision Science. 2009;86(11):E1267-75
10 Zeiss data on file. DuraVision DriveSafe clinical research study with 50 subjects. 2014
11 Zeiss data on file. Internal wearer trial (Germany) with 50 subjects; and external wearer trials with ECPs and 60 consumers (Spain). 2014
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