THE EFFECTS OF COMBINING REDUCED LUMINANCE AND INCREASED BLUR ON OLDER DRIVER SPEED AND VISUAL ACUITY

Drivers may be at more risk to themselves and other roadway users when vision is blurred or when luminance levels are reduced. Past research has investigated these visual conditions separately, finding that each degrades acuity without severely impairing steering ability. However, it is unknown how reduced luminance in combination with increased blur will affect driving performance. This study sought to quantify this combined effect on older adults\u27 comfortable driving speed and visual acuity by testing 10 participants in a driving simulator. The majority of the luminance and blur conditions are comparable to those the driving population may realistically encounter. Participants were asked to drive the speed at which they feel comfortable and could stay within their lane without using the speedometer. To ensure participants followed the instructions to stay in their lane, a percentage-of-time-in-lane measure was used to confirm no differences in steering performance existed across conditions. The older adult drivers only slowed down during the extreme blur condition; however, visual acuity was impaired by each manipulation. Interestingly, after the training conditions requiring a speed above 50 mph, drivers were given the opportunity to choose their speed and dramatically slowed down. This unexpected finding illustrates an important difference in what aging drivers choose to do in comparison with what they can do. This finding has important applied implications

A review of higher order aberrations of the human eye

Abstract: Background: This literature review is part of a research study for aberration-correcting soft contact lenses, where wavefront aberrometry was utilised. Aim: This study was conducted as part of a postgraduate research degree by the first author with particular relevance to spherical aberrations in relation to myopia and soft contact lenses, both aberration control and non-control types. Setting: This study reports on a literature review of higher order aberrations. Methods: A comprehensive review of various databases was performed, including PubMed and Google Scholar in terms of aberration control contact lenses and particular customised contact lenses for compensation of spherical aberration in myopia, was performed. Results: Wavefront sensing and Zernike polynomials are increasingly used in optometry and ophthalmology to quantify the wavefronts for an optical system such as the eye, using either lower order (LOA) or higher order aberrations (HOA). Although other mathematical methods are available, zero, 1st and 2nd orders of the Zernike polynomial expansion are LOA. Defocus ( 2 Z0 ) and astigmatism ( − and 2 2 2 Z Z2 ) are 2nd-order modes that usually can be corrected by clinicians using ordinary sphero-cylindrical compensations such as spectacle lenses. Until recently, only LOA were easily correctable by clinicians in optometry and ophthalmology. Higher order aberrations are those modes in the third radial order, n = 3 and higher, which in the past were not correctable. However, HOA contribute to only about 7% of retinal image quality and often go unnoticed by individuals, although in some instances, for example, with keratoconus or after refractive surgery, such aberrations can become more problematic. Today, new treatments are available via specially designed or customised (to an individual) rigid or soft contact lenses that are claimed to reduce or eliminate HOA such as spherical aberration ( 4 Z0 ). Conclusion: Although such specially designed or customised contact lenses have some effect on HOA, there are conflicting reports and so further investigation of this intriguing aspect remains necessary

James Jurin (1684-1750):a pioneer of crowding research?

James Jurin wrote an extended essay on distinct and indistinct vision in 1738. In it, he distinguished between "perfect,'' "distinct,'' and "indistinct vision'' as perceptual categories, and his meticulous descriptions and analyses of perceptual phenomena contained observations that are akin to crowding. Remaining with the concepts of his day, however, he failed to recognize crowding as separate from spatial resolution. We present quotations from Jurin's essay and place them in the context of the contemporary concerns with visual resolution and crowding

Doctor of Philosophy

dissertationThe ability to navigate without getting lost is an important aspect of quality of life. This dissertation evaluated how one mobility-related challenge-the increased demands of keeping oneself safe while walking with degraded vision (risk monitoring)- affects spatial learning. I proposed that spatial learning deficits result from attention competition. In Experiment 1, participants walked through two paths in a real-world indoor environment: one with simulated degraded vision, one with normal vision. Memory was greater when navigating with normal compared to degraded vision. Experiment 2 evaluated the role of risk-monitoring. Participants performed the learning task while guided (low risk- monitoring demands) or independently (high risk-monitoring demands). Access to visual information was equated for each path; half of the participants performed both trials with normal vision and half with simulated low vision. Memory was better when guided versus unguided, only in the low-vision condition, suggesting that mobility-risk demands affect spatial learning. In Experiment 3, participants walked while performing an auditory listening task both with simulated degraded vision and with normal vision. Auditory performance was poorer when navigating with simulated degraded vision, suggesting increased cognitive demands with degraded vision. Experiment 4 tested additional attentional resources that were needed when risk monitoring demands are higher. Participants with simulated low vision walked half the paths guided, half unguided. Auditory task error rates were higher in the unguided condition, suggesting more attention is required to navigate with high compared to low demands of risk monitoring. Experiment 5 used a mediational analysis to test whether attention task errors predicted spatial learning errors when each participant performed both tasks in a single experiment. Results from Experiment 5 replicated Experiments 2 and 4, but the mediational analysis results were not consistent with the hypothesis. These results are likely due to experimental design issues, but the causal role of attentional demands on spatial learning outcomes remains an open question. Together, these studies suggest that more attention is required and spatial learning is impaired when navigating with degraded viewing. This work also suggests that the cognitive process of risk monitoring contributes to both the decrease in attention and memory for the environment

gEYEded: Subtle and Challenging Gaze-Based Player Guidance in Exploration Games

This paper investigates the effects of gaze-based player guidance on the perceived game experience, performance, and challenge in a first-person exploration game. In contrast to existing research, the proposed approach takes the game context into account by providing players not only with guidance but also granting them an engaging game experience with a focus on exploration. This is achieved by incorporating gaze-sensitive areas that indicate the location of relevant game objects. A comparative study was carried out to validate our concept and to examine if a game supported with a gaze guidance feature triggers a more immersive game experience in comparison to a crosshair guidance version and a solution without any guidance support. In general, our study findings reveal a more positive impact of the gaze-based guidance approach on the experience and performance in comparison to the other two conditions. However, subjects had a similar impression concerning the game challenge in all conditions

The Effects of Headlight Intensity and Clothing Contrast on Pedestrians\u27 Own Estimated Recognition Distances at Night

Inadequate pedestrian detection is a crucial contributing factor in fatal nighttime collisions involving pedestrians. Pedestrians typically overestimate how recognizable they are to oncoming drivers and little is known about what affects pedestrians\u27 estimates of how recognizable they think they are. This study explored the extent to which pedestrians believed their conspicuity was affected by headlight intensity and clothing reflectance. Participants in four clothing conditions and in four different levels of headlight intensity walked to and from a parked vehicle until they felt recognizable to the driver. Estimated recognition distances did not change with variations in headlight intensity, suggesting that pedestrians do not use headlight illumination when judging their own conspicuity. Participants estimated shorter recognition distances when in Black clothing compared to more reflective clothing. These findings indicate a need to educate pedestrians about night visibility issues