The effects of glare and inhomogeneous visual fields on contrast detection in the context of driving

An experiment was carried out to investigate how contrast threshold for target detection is affected by the presence of glare and by extraneous light sources using the method of ascending limits. The target was located at either a foveal or a peripheral (10° right) location, glare was adjacent to the foveal location, simulating the headlamps of an oncoming vehicle, and extraneous light sources were at either foveal or peripheral (10° right or left) locations. Contrast threshold for a foveal target without glare was affected mainly by the surrounding local luminance distribution. However, in the presence of glare and also for the peripheral target (both with and without glare) the global luminance distribution matters. Glare increased the contrast needed for detection of the foveal target, but this effect was reduced by the presence of extraneous light sources that were peripheral to the target. For peripheral targets, contrast threshold was also reduced by the presence of extraneous light at a non-target location and this effect was increased in the presence of glare. Glare equations tend to be based on tests using uniform, homogenous fields: these data indicate that, in the presence of extraneous light sources, the influence of glare is over-estimated

Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements

PURPOSE: To investigate the effect of two tinted contact lenses (CL) designed for outdoor sports activity on the psychometric determination of retinal straylight using the compensation comparison method. METHODS: Thirteen emmetropic subjects were randomly fitted with two different tinted Nike Maxsight (Bausch & Lomb, Rochester, NY, USA) CL in one eye, while the contralateral eye was fitted with a clear lens made of the same material (Optima 38, Bausch & Lomb). Three valid straylight measurements were taken on each eye before and a few minutes after lens insertion, when lens stabilization had occurred. RESULTS: The subjects' mean straylight values were 0.90 +/- 0.09 at baseline and 0.95 +/- 0.10 with the clear Optima 38 CL. Straylight values were 0.97 +/- 0.10 and 1.0 +/- 0.10 log units with the amber and grey-green tinted CL, respectively. Differences in straylight between baseline (without CL) and with the clear CL in place were neither statistically significant (p = 0.066) nor was there a significant difference between baseline and the amber CL (p = 0.052). However, the grey-green CL showed a statistically significant difference from baseline (p = 0.006). Differences in straylight with the clear CL compared with the grey-green CL were also statistically different from zero (p = 0.002) showing an increased straylight value for the tinted CL. These differences were variable, but consistent for each subject, thus those showing higher or lower changes with one tinted lens tended to show the same trend with the second lens (r(2) = 0.736). CONCLUSIONS: Despite increases having been found in straylight values with tinted contact lenses, those changes are not likely to induce clinically significant changes in visual function under photopic conditions, even for the grey-green CL, which seems to increase straylight values more significantly than the amber CL. This difference between the tinted CL could suggest a wavelength dependence of straylight values, although this should be investigated further by controlling for pupil size and subjects' pigmentation, as well as by using neutral density filters

Comparison of longissimus thoracis

The aim of this trial was to compare some meat physical quality traits and the expression of some tenderness-related genes between Goudali (G, Bos indicus) breed and Italian Simmental × Goudali (SimGoud, SG, Bos taurus x Bos indicus) crossbreed. Ten G and 12 SG bulls, aged 31 ± 0.49 months, bred in the same farm and conditions in Western Highland Plateau Savannah of Cameroon were considered. Physical quality traits of longissimus thoracis (LT) muscle such as water losses, colour parameters and rheological properties were determined together with ultimate pH (pHu). The mRNA early post-mortem abundance of calpain-1 (Capn1), calpain-2 (Capn2), calpastatin (Cast), caspase 3 (Casp3), caspase 9 (Casp9), αB-crystallin (Cryab), heat shock proteins 27 (Hsp27), 40 (Hsp40) and 70 (Hsp70) was detected by qPCR. The Capn1, Cast, Hsp27 and Hsp70, early post-mortem protein content was determined by ELISA. The meat of G bulls had greater values of lightness (p < .05) and cooking loss (p < .05) than SG. The expression of Hsp70 in G was greater at mRNA (p < .05) level than SG. None of the other variables considered was significantly different between G and SG breeds. Whereas crossbreeding with Italian Simmental breed changed the colour and ameliorated the water retention capacity of G meat, tenderness and the expression of tenderness-related genes, both at mRNA and at protein level, were not significantly different between the pure local breed and the crossbreed. In comparison with pure Goudali, crossbreeding Goudali with Italian Simmental breed has a limited impact on meat traits in tropical conditions

Discomfort glare and time of day

There are strong reasons to suspect that glare sensation varies with time of the day. This study was designed to test whether such a relationship exists. Thirty subjects were exposed to an artificial lighting source at four times of the day. The source luminance was progressively increased and subjects were required to give Glare Sensation Votes (GSVs) corresponding to the level of visual discomfort experienced. Glare indices were calculated for every reported GSV, and results were statistically analysed. The findings indicated a tendency towards greater tolerance to luminance increases in artificial lighting as the day progresses. This trend was found not to be statistically related to the possible confounding variable of learning, providing evidence of an effect of time of the day on glare sensation