scholarly journals Short-term effects of aligning prisms on the objective and subjective fixation disparity in far distance

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Volkhard Schroth ◽  
Roland Joos ◽  
Ewald Alshuth ◽  
Wolfgang Jaschinski
Keyword(s):  
Binocular Vision ◽  
Exposure Duration ◽  
Fixation Disparity ◽  
Short Term ◽  
Prism Exposure ◽  
Test Conditions ◽  
Present Test ◽  
Suboptimal Condition ◽  
Cross Test ◽  
Distance Vision

Fixation disparity (FD) refers to a suboptimal condition of binocular vision. The oculomotor aspect of FD refers to a misadjustment in the vergence angle between the two visual axes that is measured in research with eye trackers (objective fixation disparity, oFD). The sensory aspect is psychophysically tested using dichoptic nonius lines (subjective fixation disparity, sFD). Some optometrists use nonius tests to determine the prisms for constant wear aiming to align the eyes. However, they do not (yet) use eye trackers. We investigate the effect of aligning prisms on oFD and sFD for 60 sec exposure duration of prisms determined with the clinically established Cross test in far distance vision. Without prisms, both types of FD were correlated with the aligning prism, while with prisms the FD was close to zero (these analyses included all base-in and base-out cases). The effect of base-in prisms on oFD was proportional to the amount of the aligning prism for the present 60 sec exposure, similar as for the 2- 5 sec exposure in Schmid et al. (2018). Thus, within 1 minute of prism exposure, no substantial vergence adaptation seems to occur in the present test conditions. Further studies may investigate intra- individual responses to different exposure times of aligning prisms in both prism directions.

Recovery from Adaptation to Moving Gratings

Perception ◽  
1977 ◽  
Vol 6 (6) ◽  
pp. 719-725 ◽  
Author(s):  
Max J Keck ◽  
Benjamin Pentz
Keyword(s):  
Time Course ◽  
Spontaneous Recovery ◽  
Motion Aftereffect ◽  
Time Decay ◽  
Short Term ◽  
Test Grating ◽  
Test Conditions ◽  
Sinusoidal Gratings ◽  
Short Term Adaptation

Short-term adaptation to moving sinusoidal gratings results in a motion aftereffect which decays in time. The time decay of the motion aftereffect has been measured psychophysically, and it is found to depend on (i) the spontaneous recovery from the adapted state, and (ii) the contrast of the test grating. We have measured the decays for various test conditions. An extrapolation of the measurements allows us to obtain a decay which represents the time course of the spontaneous recovery of the direction-sensitive mechanisms.

Modeling the blood lactate kinetics at maximal short-term exercise conditions in children, adolescents, and adults

2005 ◽  
Vol 99 (2) ◽  
pp. 499-504 ◽  
Author(s):  
Ralph Beneke ◽  
Matthias Hütler ◽  
Marcus Jung ◽  
Renate M. Leithäuser
Keyword(s):  
Blood Lactate ◽  
Muscle Mass ◽  
Body Mass ◽  
Short Term ◽  
Wingate Anaerobic Test ◽  
Blood Compartment ◽  
Test Conditions ◽  
Age Related ◽  
Adolescents And Adults ◽  
Anaerobic Test

Whether age-related differences in blood lactate concentrations (BLC) reflect specific BLC kinetics was analyzed in 15 prepubescent boys (age 12.0 ± 0.6 yr, height 1.54 ± 0.06 m, body mass 40.0 ± 5.2 kg), 12 adolescents (16.3 ± 0.7 yr, 1.83 ± 0.07 m, 68.2 ± 7.5 kg), and 12 adults (27.2 ± 4.5 yr, 1.83 ± 0.06 m, 81.6 ± 6.9 kg) by use of a biexponential four-parameter kinetics model under Wingate Anaerobic Test conditions. The model predicts the lactate generated in the extravasal compartment (A), invasion ( k1), and evasion ( k2) of lactate into and out of the blood compartment, the BLC maximum (BLCmax), and corresponding time (TBLCmax). BLCmax and TBLCmax were lower ( P < 0.05) in boys (BLCmax 10.2 ± 1.3 mmol/l, TBLCmax 4.1 ± 0.4 min) than in adolescents (12.7 ± 1.0 mmol/l, 5.5 ± 0.7 min) and adults (13.7 ± 1.4 mmol/l, 5.7 ± 1.1 min). No differences were found in A related to the muscle mass (AMM) and k1 between boys (AMM: 22.8 ± 2.7 mmol/l, k1: 0.865 ± 0.115 min−1), adolescents (22.7 ± 1.3 mmol/l, 0.692 ± 0.221 min−1), and adults (24.7 ± 2.8 mmol/l, 0.687 ± 0.287 min−1). The k2 was higher ( P < 0.01) in boys (2.87 10−2 ± 0.75 10−2 min−1) than in adolescents (2.03 × 10−2 ± 0.89 × 10−2 min−1) and adults (1.99 × 10−2 ± 0.93 × 10−2 min−1). Age-related differences in the BLC kinetics are unlikely to reflect differences in muscular lactate or lactate invasion but partly faster elimination out of the blood compartment.

scholarly journals Effect of video game playing and a glucose preload on subjective appetite, subjective emotions, and food intake in overweight and obese boys

2019 ◽  
Vol 44 (3) ◽  
pp. 248-254 ◽  
Author(s):  
Brandon J.F. Gheller ◽  
Julia O. Totosy de Zepetnek ◽  
Jo M. Welch ◽  
Melissa D. Rossiter ◽  
Bohdan Luhovyy ◽  
...  
Keyword(s):  
Food Intake ◽  
Video Game ◽  
Primary Role ◽  
Game Playing ◽  
Healthy Weight ◽  
Short Term ◽  
Physiological Factors ◽  
Video Game Playing ◽  
Test Conditions

Video game playing (VGP) is associated with overweight/obesity (OW/OB). VGP and caloric preloads in the pre-meal environment influence short-term food intake (FI) in healthy-weight children. Therefore, the purpose of the present study was to examine the effect of pre-meal VGP and a glucose preload on subjective emotions, subjective appetite, and FI in boys with OW/OB. On 4 separate mornings, boys with OW/OB (n = 22; mean ± SD: age = 11.9 ± 1.6 years; body mass index percentile = 94.3 ± 3.9) participated in 4 test conditions. Two hours after a standardized breakfast, boys consumed equally sweetened preloads (250 mL) of sucralose (0 kcal) or glucose (200 kcal), with or without 30 min of subsequent VGP. Immediately after each test condition, FI was evaluated during an ad libitum pizza meal. Subjective appetite was measured at 0 (baseline), 15, and 30 min. Subjective emotions (aggression, anger, excitement, disappointment, happiness, upset, and frustration) were measured at 0 and 30 min. VGP did not affect FI, but the glucose preload decreased FI compared with the sucralose control (Δ = −103 ± 48 kcal, p < 0.01). However, cumulative FI (preload kcal + meal kcal) was 9% higher after the glucose preload (p < 0.01). Subjective appetite increased with time (p < 0.05) but was not influenced by preload or VGP. Frustration was the only subjective emotion that increased following VGP (p < 0.01). A glucose preload, but not VGP, suppressed FI in boys with OW/OB, suggesting a primary role of physiological factors in short-term FI regulation.

Exposure Duration and Composition are Important Variables to Predict Short-Term Toxicity of Effluents to a Tropical Copepod, Acartia Sinjiensis

2021 ◽  
Author(s):  
Sarah Stone ◽  
Kitty S. McKnight ◽  
Cristoph Naab ◽  
Darren J. Koppel ◽  
Monique T. Binet ◽  
...  
Keyword(s):  
Exposure Duration ◽  
Short Term

Fixation Disparity as a Function of Viewing Distance and Prism Load

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 76-76
Author(s):  
W Jaschinski
Keyword(s):  
Binocular Vision ◽  
Temporal Variability ◽  
Angular Size ◽  
Psychophysical Method ◽  
Viewing Distance ◽  
Fixation Disparity ◽  
Average Standard Deviation ◽  
Natural Interaction ◽  
Near Vision ◽  
Constant Distance

In binocular vision, fixation disparity is present when a fixation point falls within Panum's area, but not on corresponding retinal points. To investigate the effect of vergence load, fixation disparity was measured at viewing distances of 20, 30, 40, 60, and 100 cm (while the test subtended a constant angular size) by the psychophysical method of dichoptically presented nonius lines with a central fusion stimulus. As the viewing distance was shortened from 100 to 20 cm, mean fixation disparity changed monotonically from 1 min arc esophoria (ie the eyes converged in front of the target) to 3 min arc exophoria. The average standard deviation of the psychometric function, which is a measure of the temporal variability of vergence, was smallest at 100 cm (when fixation disparity was esophoric) and increased at shorter distances. Fixation disparity was also measured at a constant distance of 40 cm, but with prisms in front of the eyes that induced the same vergence angles as would be induced by viewing distances between 20 and 100 cm. The slope of these conventional ‘fixation disparity curves’ as a function of prism load correlated with the slope of fixation disparity as a function of viewing distance ( r=0.39, p=0.02, n=25). However, testing at different distances, as introduced here, has the advantage of preserving the natural interaction between vergence and accommodation. Since the change of fixation disparity with distance differed reliably among subjects (with a test — retest correlation of 0.65 in 34 subjects with good binocular vision) this measure may be useful for identifying subjects who are prone to near-vision complaints.

scholarly journals Hoya Eyegenius®: New Method for Measuring and Correcting Fixation Disparity

2017 ◽  
Vol 71 (5) ◽  
pp. 392-396
Author(s):  
Volkhard Schroth ◽  
Olga Prenat ◽  
Natalia Vlasak ◽  
Roger Crelier
Keyword(s):  
Binocular Vision ◽  
Direct Conversion ◽  
New Method ◽  
Digital Environment ◽  
Fixation Disparity ◽  
Blurred Vision ◽  
Digital Devices ◽  
Innovative Method ◽  
Normal Binocular Vision

Abstract Many things interfere with good binocular vision in nowadays modern digital environment: long periods spent looking at screens and switching between different digital devices at short distances. Vision-related or asthenopic complaints such as headaches, tired and burning eyes or blurred vision can be experienced by many people. Prescribing prismatic correction for fixation disparity can help to reduce these symptoms. A new, highly innovative method for measuring and correcting fixation disparity has been developed - HOYA EyeGenius®. The HOYA EyeGenius® method includes the unique examination procedures, pre-tests and fixation disparity measurements at far and near distances. The pre-tests allow to include patients with asthenopic complaints only with normal binocular vision and exclude cases with abnormal binocular vision. The main innovation of EyeGenius is based on direct conversion of the fixation disparity value into a prism amount. Therefore, the trial prismatic lenses are not used during the test. The use of digital devices makes this method interactive and minimizes the influence of the examiner.

scholarly journals Aem Analyses of SRL 131 Glass Altered as a Function of SA/V

1991 ◽  
Vol 257 ◽  
Author(s):  
James J. Mazer ◽  
John K. Bates ◽  
Bruce M. Biwer ◽  
C. R. Bradley
Keyword(s):  
Experimental Studies ◽  
Volume Ratio ◽  
Scaling Factor ◽  
Experimental Results ◽  
Geologic Repository ◽  
Short Term ◽  
Natural Systems ◽  
Test Conditions ◽  
Solution Volume

Experimental studies of silicate glass/water reactions at low temperatures have previously identified the glass surface area-to-solution volume ratio (SA/V) as a significant rate determining parameter [1-4]. The value produced when SA/V is multiplied by reaction time, hereafter referred to as SVT, has been proposed as a scaling factor for comparing experimental results collected under different test conditions and for extrapolating short-term results to longer periods of time. Developing an understanding of the effect of SAN is needed for modeling experimental results where SA/V ranges in value or may vary during experiments. It is also useful to understand the effect of SA/V for modeling natural systems where this value almost certainly varies, such as during the hydrothermal diagenesis of natural glasses or projecting the long-term reaction of water and borosilicate nuclear waste glass in a geologic repository.

Test Stand for Durability Tests of Rotating Elements of Office Chairs

2014 ◽  
Vol 223 ◽  
pp. 155-162 ◽  
Author(s):  
Andrzej Zbrowski ◽  
Krzysztof Matecki
Keyword(s):  
Test Stand ◽  
Point Of View ◽  
Static Loads ◽  
Certification Tests ◽  
Test Conditions ◽  
Present Test ◽  
Normative Requirements ◽  
Design And Construction

This paper presents the purpose, concept, principles of functioning, design and construction of a stand intended for testing the durability of rotational elements of office chairs. It shows the use of the stand for certification tests in accordance with the PN-EN 1335:2009 standard. It also discusses how tests on swivelling and the durability of wheels and the base of office chairs should be conducted using the developed stand. The authors present test conditions and discuss the instrumentation necessary to induce static loads during the investigations. They also identify the possibilities to perform other tests on the stand by introducing to the existing research instruments additional instrumentation necessary from the point of view of the above listed standard. The possibility of adjusting the stand to the prospective changes in normative requirements and the needs of individual users are also described.

scholarly journals Creep Behaviour of Modified Mar-247 Superalloy

2016 ◽  
Vol 61 (2) ◽  
pp. 701-704 ◽  
Author(s):  
M. Cieśla ◽  
M. Mańka ◽  
F. Binczyk ◽  
P. Gradoń
Keyword(s):  
Creep Behaviour ◽  
Rupture Life ◽  
Coarse Grained ◽  
Short Term ◽  
Creep Tests ◽  
Nickel Based Superalloy ◽  
Test Conditions ◽  
Accelerated Creep ◽  
Term Creep ◽  
Short Term Creep

Abstract The paper presents the results of analysis of creep behaviour in short term creep tests of cast MAR-247 nickel-based superalloy samples made using various modification techniques and heat treatment. The accelerated creep tests were performed under temperature of 982 °C and the axial stresses of σ = 150 MPa (variant I) and 200 MPa (variant II). The creep behaviour was analysed based on: creep durability (creep rupture life), steady-state creep rate and morphological parameters of macro- and microstructure. It was observed that the grain size determines the creep durability in case of test conditions used in variant I, durability of coarse-grained samples was significantly higher.

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