Self-motion illusions from distorted optic flow in multifocal glasses

Yannick Sauer,Malte Scherff,Markus Lappe,Katharina Rifai,Niklas Stein,Siegfried Wahl

doi:10.1016/j.isci.2021.103567

Yannick Sauer, Malte Scherff + Show 4 more

Open Access

https://doi.org/10.1016/j.isci.2021.103567

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Journal: iScience	Publication Date: Dec 8, 2021
Citations: 5	License type: cc-by

Affiliation: University of Münster, University of Tübingen

Abstract

SummaryProgressive addition lenses (PALs) are ophthalmic lenses to correct presbyopia by providing improvements of near and far vision in different areas of the lens, but distorting the periphery of the wearer's field of view. Distortion-related difficulties reported by PAL wearers include unnatural self-motion perception. Visual self-motion perception is guided by optic flow, the pattern of retinal motion produced by self-motion. We tested the influence of PAL distortions on optic flow-based heading estimation using a model of heading perception and a virtual reality-based psychophysical experiment. The model predicted changes of heading estimation along a vertical axis, depending on visual field size and gaze direction. Consistent with this prediction, participants experienced upwards deviations of self-motion when gaze through the periphery of the lens was simulated, but not for gaze through the center. We conclude that PALs may lead to illusions of self-motion which could be remedied by a careful gaze strategy.

Highlights

With increasing age, accommodation capabilities of the human eye decrease and it becomes harder to focus on nearby objects (Atchison, 1995)
Optic flow fields were calculated for the motion scenario with and without distortions using a ray tracing approach in which for each point in the scene the distorted and undistorted positions in the image plane are calculated followed by calculation of the optical motion in the image plane
Virtual reality experiment on distorted self-motion perception in humans To study human perception under the influence of Progressive addition lenses (PALs) distortions in an isolated experimental environment, we developed a simulation of optical distortions in virtual reality (VR) (Stein et al, 2021)

Summary

Introduction

Accommodation capabilities of the human eye decrease and it becomes harder to focus on nearby objects (Atchison, 1995). The far zone in the upper area of the lens corrects far vision, whereas the near zone in the lower area of the lens has additional optical power to reduce accommodative demand when focusing on close objects. Between these two zones, there is a progressive increase in optical power which inevitably produces unwanted astigmatism (Sheedy et al, 2005). There is a progressive increase in optical power which inevitably produces unwanted astigmatism (Sheedy et al, 2005) This causes blur and skew distortions in the periphery.

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