Effects of transient adaptation on drivers’ visual performance in road tunnel lighting

Lighting for road tunnels: The influence of CCT of light sources on reaction time

The influences of tunnel lighting environment on drivers’ peripheral visual performance during transient adaptation

Influence of luminance and luminance longitudinal uniformity of tunnel lighting on drivers' comprehensive visual performance

A series of three experiments were conducted to investigate the relation between shifts of attention in depth and subjects' visual performance or peripheral environment luminance in three-dimensional (3-D) space. Previous researchers have examined various aspects of shifts of visual attention in 3-D space. However, there were few studies to study the relationship of depth attention and peripheral environment luminance. Firstly, visual function performance of subjects was tested by means of visual measurement apparatus in experiment 1, and experimental data was divided into two groups. And then, mean reaction time (RT) of subjects was examined by changing peripheral environment luminance using a semi-realistic setting, the depth attention experiment apparatus in experiment 2. Finally, changing forecast degree examination was conducted to subjects with low visual adaptability in order to reveal the relation between delay of reaction time and forecast degree in experiment 3. The major results was shown that (1) visual performance of subjects had an individual difference; (2) shifts of attention from far space to near space was faster than the reverse under each different condition; (3) the training for visual adaptive ability can improved visual performance of subjects.

To evaluate the short-term effects of three myopia-control lenses, which impose peripheral myopic defocus while providing clear central vision, on central and peripheral visual performance in myopic children. Twenty-one myopic children were enrolled in the study. Central visual performance was assessed using the quick contrast sensitivity function. Peripheral visual performance was evaluated by measuring peripheral contrast threshold and global motion perception, while subjects maintained fixation through the central portion of the lens. Single-vision spectacle lenses (SVL), spectacle lenses with highly aspherical lenslets (HAL) and defocus-incorporated soft contact (DISC) lenses were evaluated in random order, followed by orthokeratology (OK) lenses. All tests were performed monocularly on the right eye. The area under the log contrast sensitivity function (AULCSF) with DISC lenses was lower than that with SVL (1.14 vs. 1.40, p < 0.001) and HAL (1.14 vs. 1.33, p = 0.001). HAL increased the temporal visual field contrast threshold compared with OK lenses (p = 0.04), and OK lenses decreased the superior visual field contrast threshold compared with that of SVL (p = 0.04) and HAL (p = 0.005). HAL also increased the peripheral coherence threshold for identifying the contraction movement compared with OK lenses (p = 0.01). The short-term use of these optical interventions for myopia control exhibited measurable differences in central and peripheral visual performance. Relevant attention could be paid to these differences, especially when children switch to different treatments. DISC lenses exhibited worse central contrast sensitivity than SVL and HAL. Imposing peripheral defocus signals did not affect children's peripheral visual performance compared with SVL. However, considering the poorer peripheral visual performance provided by HAL, OK lenses are recommended for children if there are specific demands for global scene recognition and motion perception.

Peripheral (out-to-the-side) vision is important for general mobility and tasks such as driving. This study evaluated appropriateness of testing methods used to measure peripheral optics and visual performance. Peripheral optics measurements depended on the instrument used to measure them. The choice of either head or eye movements to set up peripheral optics measurements was not critical, even when contact lenses were worn. The nature of targets, in terms of size and abrupt or gradual loss of contrast near the edge, affected peripheral detection. To measure peripheral contrast detection accurately in the presence of blur, fine spatial frequency sampling was required.

Central and peripheral visual performance in myopes: Contact lenses versus spectacles

Based on the perceived contrast method in road tunnel lighting, Commission Internationale de l´Eclairage (CIE) defined the contrast revealing coefficient qc. The research report CIE 189-2010 recommended that contrast revealing coefficient qc was one of the indicators of tunnel lighting quality evaluation system. Many studies suggested that the value of qc was 0.6 under counter-beam lighting in tunnel lighting threshold zone. The value of contrast revealing coefficient was 0.2 under symmetric lighting. However, no studies have recommended the optimal value of contrast revealing coefficient under different lighting systems. The optimal value of contrast revealing coefficient was closely related to visual efficacy and driving safety in road tunnel lighting. Based on the range values of contrast revealing coefficient and visual efficacy experiment, this paper aimed to study the optimal values of contrast revealing coefficient under different lighting systems. The research results were as follows: the optimal value of contrast revealing coefficient qc was 0.20 under symmetric lighting and the optimal value of qc was 0.85 under counter-beam lighting. The optimal value of contrast revealing coefficient was 0.17 under pro-beam lighting.

Despite having comparable levels of visual functions, functional performance in a visual task may vary. Children with albinism had better visual search performance when compared with their other peers with visual impairments (VIs). Upon further investigation, the presence of nystagmus seemed to have a role in this performance outcome. Individuals with albinism and VI (AVI) are shown to have near-normal reading speed akin to normally sighted (NS), whereas individuals with other causes of VI are known to have difficulty. We investigated if a similar observation can be obtained in other functional vision domains, such as visual search. Towards this aim, visual search performance was compared among three groups of children (NS, AVI, and VI). Real-world images were presented on a computer screen along with a search target. Participants were asked to find and point to the search target within these images. A total of 150 trials were given to each child. Reaction time (time taken to find the target), accuracy, and integrated search performance score (a composite score accounting for time-accuracy trade-off) were analyzed. Comparisons between AVI and VI used univariate ANOVA after controlling for other factors (age, visual acuity, and contrast sensitivity). Ninety-seven children (age: 5 to 17 years) participated (n = 26 NS, 31 AVI, and 40 VI). As expected, NS children had better performance (p≤0.005). While the accuracy of AVI was comparable to those with VI (p=0.068), AVI were significantly faster (p=0.002) and had a better integrated visual search performance score (p<0.001). Further subanalysis showed the AVI group had better performance (p<0.001) when compared with those with VI but without nystagmus (n = 23) and not when compared with the VI group with nystagmus (p=0.059). No difference in performance was observed between the two VI groups (p=0.081). Despite having comparable visual functions, the AVI group performed better in a functional vision task than their peers with VI. Nystagmus seems to play a role in this visual performance. Further studies are needed to investigate this.

In 2010, the CIE published a recommended system for mesopic photometry based on visual performance. According to this system, scenes illuminated at mesopic levels with light sources of high S/P ratio, will produce better visual performance than those illuminated with light sources of a lower S/P ratio at equal photopic luminance. However, there could be other factors affected by SPD that, when quantified, could lead to a contradictory final effect. The scope of this paper was to evaluate how road lighting is affected by the spectral road surface reflectance and by the human eye transmittance as people get older. Our results suggest that the benefits of considering the mesopic vision effect for light sources with high S/P ratios are totally counteracted by the other two effects at mesopic luminances between 0.75 cd/m2 and 1.73 cd/m2 for people between 20 and 60 years of age, depending on the light source and the age of observers.

The Loxahatchee National Wildlife Refuge (Refuge) is affected by inflows containing elevated contaminant concentrations originating from agricultural and urban areas. Water quality was determined using three networks: the Northern Refuge (NRN), the Southern Refuge (SRN), and the Consent Decree (CDN) monitoring networks. Within these networks, the Refuge was divided into four zones: (1) the canal zone surrounding the marsh, (2) the perimeter zone (0 to 2.5 km into the marsh), (3) the transition zone (2.5 to 4.5 km into the marsh), and (4) the interior zone (>4.5 km into the marsh). In the NRN, alkalinity (ALK) and conductivity (SpC) and dissolved organic carbon, total organic carbon, total dissolved solids (TDS), Ca, Cl, Si, and SO(4) concentrations were greater in the perimeter zone than in the transition or interior zone. ALK, SpC, and SO(4) concentrations were greater in the transition than in the interior zone. ALK, SpC, and TDS values, Ca, SO(4), and Cl had negative curvilinear relationships with distance from the canal toward the Refuge interior (r(2) = 0.78, 0.67, 0.61, 0.77, 0.62, and 0.57, respectively). ALK, TB and SpC, and Ca and SO(4) concentrations decreased in the canal and perimeter zones from 2005 to 2009. Important water quality assessments using the SRN and CDN cannot be made due to the sparseness and location of sampling sites in these networks. The number and placement monitoring sites in the Refuge requires optimization based on flow pattern, distance from contaminant source, and water volume to determine the effect of canal water intrusion on water quality.

The Loxahatchee National Wildlife Refuge (Refuge) developed as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources flowing into canals surrounding the west side and from urban and horticultural areas flowing into canals surrounding the eastern side of the Refuge. We analyzed water quality sampled at 40 sites divided into eastern and western areas and four zones in the Refuge. We defined four zones as the canals surrounding the Refuge marsh, the perimeter zone, the transition zone, and the interior zone. The canal receiving agricultural inflows had greater alkalinity and conductivity (SpC), Si and SO4 but lower turbidity and total suspended solids than the canal receiving urban and horticultural inflows. Alkalinity, total dissolved solids (TDS), SpC, Ca, Cl, and SO4 concentrations were greater in the perimeter than in transition and interior zones. Alkalinity and SpC values and SO4 concentrations were greater in the transition than in interior zone. Alkalinity, SpC, and TDS values and Ca, SO4, and Cl concentrations correlated in negative curvilinear relationships with distance from the canal (r2 = 0.78, 0.70, 0.61, 0.78, 0.64, 0.57, respectively). Analysis of multiple water quality parameters may reveal the complexity of interactions that might be overlooked in a simple single parameter analysis. These data show an impact of canal water containing high nutrient concentrations on water quality flowing from the canal towards the Refuge interior.

The impact of LED spectrum and correlated color temperature on driving safety in long tunnel lighting

Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.

Purpose Purpose: Under night driving conditions visual performance is compromised and become worse with disability glare, age and certain ocular pathologies. The aim of this study was to analyze mesopic visual function of young subjects.Methods Methods: The sample included 37 right eyes of healthy young adults (22.2 ± 1.8 years). The selected criteria were: Best‐corrected VA of at least 0.04 logMAR, and refraction ≤± 3.75. Under mesopic (0.1 to 0.2 cd/m2) luminance conditions and with the best‐optical correction in the right eye, the logMAR VA was measured using high‐contrast (HC‐96%) and low‐contrast (LC‐10%) logMAR Bailey‐Lovie letter charts, and the mesopic contrast sensitivity (CS) without / with glare was assessed with Mesotest II. The intraocular straylight was measured with the C‐Quant.Results Results: Under mesopic conditions, the HC and LC logMAR VA was 0.28 ± 0.1 and 0.70 ± 0.1 respectively, showing a significant correlation between them (Pearson’s correlation = 0.75; p&lt; 0.00); The mesopic log CS without glare was 0.19 ± 0.1 and with glare was 0.11 ± 0.1. Disability glare induced a 42% decrease in mesopic log CS (p &lt; 0.00). LC logMAR VA was significant correlated with mesopic log CS without and with glare (Pearson’s correlation = 0.4, p&lt; 0.02, and 0.42, p&lt; 0.02 respectively). The intraocular straylight Log (s) was 0.87 ± 0.1, but did not show any significant association with logMAR VA nor the log CS without and with glare under mesopic luminance conditions.Conclusion Conclusions: The results indicated that mesopic assessment of the low contrast logMAR VA and log CS without and with glare might potentially predict the glare visual performance under night driving conditions.