By Ulrich Schiefer & Judith Ungewiß, Aalen University
Ulrich Schiefera,b, Judith Ungewißa, Michael Wörnera,c and the ContrastVal Study Group
a Competence Center „Vision Research“, Study Course Ophthalmic Optics, University of Applied Sciences Aalen, FRG
b Department of Ophthalmology, University of Tübingen/FRG
c BlickShift Inc., Stuttgart/FRG
Optical lenses are usually evaluated by ray tracing methods or questionnaires: Ray tracing is well suited to characterize the image quality at the retina level whereby the image processing in the downstream visual pathway is not taken into account. Questionnaires are subjective tools with an inherent lack of standardization.
The aim of this approach is to develop a psychophysical test set-up that records the individual’s visual performance or impairment in a location-specific manner within the highly standardized environment of a driving simulator. LED arrays moved via cable robots serve as moving or static glare sources.1
Individual local visual acuity and/or contrast sensitivity thresholds are assessed by eight-position LANDOLT C’s. The stimuli can be presented at various locations within the set-up (e.g. projection screen, dashboard, navigation monitor, rear mirrors etc.), utilizing static and moving optotypes, respectively2. The vector origins of the moving stimuli can be placed within the center of a glare source in order to assess the individual, location-related extent of the visual impairment due to halo or starburst. Local threshold variability and individual response time are assessed by repeated presentations and vector placements within unaffected visual field areas.
The set-up is being used for characterizing the visual effects of media opacities (cataract) in motorists (ContrastVal study)3 for benchmarking the impact of any kind of optical corrections, such as spectacle lenses, contact lenses, intraocular lenses (JJ-EYHANCE study)4 or other (surgical) refractive procedures.
1 German Patent and Trademark Office: Deutsches Patent Nr. 10 2017 126 741.7
2 German Patent and Trademark Office: Deutsches Patent Nr. 10 2019 121 602.8
3 ClinicalTrials.gov Identifier: NCT03169855
4 ClinicalTrials.gov Identifier: NCT04059289
Acknowledgement: These studies are supported by the German Social Accident Insurance, Berlin/FRG and by a JOHNSON & JOHNSON/AMO, Dublin/Ireland, IIT grant.