scholarly journals Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Eliza Maria da Costa Brito Lacerda ◽  
Monica Gomes Lima ◽  
Anderson Raiol Rodrigues ◽  
Cláudio Eduardo Correa Teixeira ◽  
Lauro José Barata de Lima ◽  
...  
Keyword(s):  
Visual Field ◽  
Contrast Sensitivity ◽  
Organic Solvents ◽  
Color Discrimination ◽  
Temporal Contrast ◽  
Spatial Frequencies ◽  
Exposed Workers ◽  
Occupationally Exposed ◽  
Snellen Chart ◽  
Psychophysical Evaluation

The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old) were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry) and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test—FM100). Spatial contrast sensitivities of exposed workers were lower than the control at spatial frequencies of 20 and 30 cpd whilst the temporal contrast sensitivity was preserved. Visual field losses were found in 10–30 degrees of eccentricity in the solvent exposed workers. The exposed workers group had higher error values of FM100 and wider color discrimination ellipses area compared to the controls. Workers occupationally exposed to organic solvents had abnormal visual functions, mainly color vision losses and visual field constriction.

Contrast Sensitivity and Visual-Field Thresholds in Patients with Thyroid Optic Neuropathy

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 194-194
Author(s):  
J Jankauskiene ◽  
R Lukauskiene ◽  
B Mickiene
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Contrast Sensitivity ◽  
Optic Neuropathy ◽  
Control Group ◽  
Ophthalmological Examination ◽  
Threshold Test ◽  
Spatial Frequencies ◽  
Snellen Visual Acuity ◽  
The Mean

Thyroid optic neuropathy is one of the most troubling complications of endocrine ophthalmopathies. It is related to the degree of extraocular muscle swelling in the apex of the orbit. The purpose of this study was to investigate contrast sensitivity and visual-field thresholds in patients with thyroid optic neuropathy. We examined twenty-two patients aged 29 – 63 years (mean 45.3 years). The control group consisted of fifteen healthy persons of similar age. Contrast sensitivity was measured by means of Volkov's charts (sinusoidal gratings) at eight spatial frequencies from 17.5 to 0.46 cycles deg−1. The visual field was investigated with a static automatic perimeter (Allgan Humphrey Field Analyzer) by means of the central 30-2 threshold test. All patients underwent a complete ophthalmological examination including best corrected Snellen visual acuity, fundus copy, and proptosis measurement with the Hertel exophthalmometer. The mean proptosis of patients was 19.4 mm. Fifteen of the patients had decreased visual acuity. Contrast sensitivity at low spatial frequencies was significantly reduced in the patients. It was established that a reduction of visual-field threshold accompanies the decrease of visual acuity. Our results show that contrast sensitivity and visual-field threshold testing are very sensitive at detecting early optic neuropathy and may be a useful means of following patients after treatment.

scholarly journals Morbidity patterns of workers employed in pharmaceutical-chemical industry

2007 ◽  
Vol 135 (3-4) ◽  
pp. 184-190 ◽  
Author(s):  
Aleksandar Milovanovic ◽  
Branko Jakovljevic ◽  
Jovica Milovanovic ◽  
Katarina Paunovic ◽  
Dragan Ilic ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Working Conditions ◽  
Chemical Industry ◽  
Control Group ◽  
Pharmaceutical Chemical ◽  
Work Activity ◽  
Pharmaceutical Chemical Industry ◽  
Exposed Workers ◽  
Occupationally Exposed ◽  
Physical Examinations

Introduction. Work in pharmaceutical-chemical industry is characterized by exposure to numerous hazards, both physical (microclimate, illumination, noise) and chemical (organic solvents). Organic solvents can cause damage to many organic systems and have carcinogenic, teratogenic and mutagenic effects. Objective. The aim of this study was to analyze patterns of chronic morbidity of workers employed in pharmaceuticalchemical industry during 2002. Method. The study was conducted in the pharmaceutical- chemical industry "Zdravlje" Leskovac in 2002. A total of 143 workers in workplaces with special working conditions - exposed to chemical hazards as well as 40 workers from control group took part in the study. The physical examinations of the participants were performed at the Department of Occupational Health in Health Center, Leskovac. Results. Heart diseases were the most frequent both among exposed workers (17.8%) and in control group (33.3%). Respiratory diseases were at the second place (16.9% in the exposed group, and 7.4% in control group). Arterial hypertension was diagnosed in 14.7% workers occupationally exposed to hazards, and in 12.5% workers from control group (p>0.05). Chronic bronchitis was diagnosed in 17.5% of the exposed workers and in only 5.0% of controls (p>0.05). The highest prevalence of diseases in both groups was observed among workers aged 40-49 years, with 20-29 years of exposure working time. 73.4% of the exposed workers and 85% of control workers were capable of work (p>0.05). Conclusion. Workers occupationally exposed to hazards in pharmaceutical-chemical industry have higher prevalence of various diseases compared to non-exposed workers, which can be the result of work, working conditions and work activity. Preventive measures should be directed towards the decrease of occupational hazards and unfavorable working conditions and increase of work protection. Regular physical examinations of workers are of prime importance for the prevention of occupational morbidity, traumatism and invalidity. .

Evidence of a Global Oblique Effect in Human Extrafoveal Vision

Perception ◽  
1996 ◽  
Vol 25 (5) ◽  
pp. 523-530 ◽  
Author(s):  
Jonathan S Pointer
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Oblique Effect ◽  
Spatial Summation ◽  
Single Subject ◽  
Frequency Dependency ◽  
Spatial Frequencies ◽  
Sensitivity Data

Analysis of recently published human contrast-sensitivity data obtained along the cardinal and major oblique visual-field meridians of a single subject has demonstrated a consistently greater sensitivity at a given eccentricity to horizontally oriented as compared with obliquely oriented gratings. This difference was evident not only at foveal but also at several eccentric loci over a range of low to medium spatial frequencies. This observation is to be distinguished in extrafoveal fixation from the well-documented oblique effect, which describes the variation in sensitivity with orientation at a single visual-field locus. With periodic stimuli which were well localised in space and frequency, and had comparable spatial-summation properties, a spatial-frequency dependency of what could be termed the global oblique effect could be demonstrated along isoeccentric contours centred on the fovea (eccentricity 0 deg) out to an eccentricity of at least 40 deg.

scholarly journals Effects of Ocular Dominance on Contrast Sensitivity in Middle-Aged People

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Gökhan Pekel ◽  
Neşe Alagöz ◽  
Evre Pekel ◽  
Cengiz Alagöz ◽  
Ömer Faruk Yılmaz
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Ocular Dominance ◽  
Testing System ◽  
Middle Aged ◽  
Aged People ◽  
Spatial Frequencies ◽  
Uncorrected Visual Acuity ◽  
Snellen Chart ◽  
Aged Subjects

Purpose. Our aim was to compare contrast sensitivity values of the dominant and nondominant eyes of healthy middle-aged subjects. Material and Methods. Ninety eyes of 45 healthy middle-aged subjects (30 males and 15 females) were included in this study. Patients were aged between 40 and 60 years, having uncorrected visual acuity (UCVA) of 20/25 or better (Snellen chart). Ocular dominance was determined by hole-in-the-card test. Functional acuity contrast testing (F.A.C.T.) was measured using the Optec 6500 vision testing system (Stereo Optical Co. Inc., Chicago, IL, USA) under both photopic and mesopic conditions. Results. At all spatial frequencies (1.5, 3, 6, 12, and 18 cpd), under mesopic conditions, the contrast sensitivity values of the dominant eyes were slightly greater than those of the nondominant eyes; but only 18 cpd spatial frequency measurements’ difference was statistically significant (P=0.035). Under photopic conditions, the contrast sensitivity values of the dominant eyes and non-dominant eyes were similar at all spatial frequencies (P>0.05). Conclusions. The photopic and mesopic contrast sensitivity values of dominant and nondominant eyes of healthy middle-aged people were similar at all spatial frequencies, except at mesopic 18 cpd spatial frequency.

Functional acuity contrast sensitivity assessment in young and middle age healthy persons at the day time with and without glare

2014 ◽  
Vol 21 (1) ◽  
pp. 21-25
Author(s):  
Jelena Sidorova ◽  
Rasa Čiumbaraitė ◽  
Džastina Čebatorienė ◽  
Mantas Banevičius ◽  
Rasa Liutkevičienė
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Middle Age ◽  
Age Groups ◽  
Sensitivity Assessment ◽  
Spatial Frequencies ◽  
Snellen Chart ◽  
Group 2 ◽  
Healthy Persons ◽  
Group 1

Background. As people age, their vision becomes less clear; they can clearly see big objects but experience problems discerning minor things and minor details. The functional acuity contrast test is a very sensitive method used for visual system evaluation which may help to detect the beginning of the disease in case the visual acuity is still normal. Purpose. To determine functional acuity contrast sensitivity in young and in middle age healthy persons at the day time with and without glare. Materials and methods. We examined 40–49 yrs (Group 1), and 50– 59 yrs (Group 2) healthy persons. The typical Snellen chart (the direc­tion of the gap in Landolt C) was used for the non-corrected and the bestcorrected visual acuity testing. Functional acuity contrast sensitivity was measured employing a Ginsburg Box, VSCR- CST-6500, at the day time with and without glare. Results. Functional acuity contrast sensitivity remained very similar in the age groups of 40–49 years and 50–59 years. However, statistically, it significantly decreased at day time without glare (18 cycle / degree) spatial frequencies (p = 0.05). Results in Group 1 as compared to Group 2 decreased from 3.09% to 51.7% at the day time without glare and from 2.16% to 11.61% at the day time with glare. Conclusion. The facts are that contrast sensitivity remained very similar in the age groups of 40–49 years and 50–59 years at the day time with and without glare.

Flicker Contrast Sensitivity in Normal and Specifically Disabled Readers

Perception ◽  
1987 ◽  
Vol 16 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Frances Martin ◽  
William Lovegrove
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Temporal Frequency ◽  
Temporal Contrast ◽  
Control Subjects ◽  
Visual Systems ◽  
Spatial Frequencies ◽  
Disabled Readers ◽  
Transient System

Temporal contrast sensitivity for counterphase flicker was determined for specifically disabled and normal readers to investigate whether the two groups differ in the functioning of their transient systems. In experiment 1, temporal contrast sensitivity was measured over a range of temporal frequencies with a spatial frequency of 2 cycles deg−1. Disabled readers were less sensitive than the control subjects at all temporal frequencies. In experiment 2, temporal contrast sensitivity was measured at a temporal frequency of 20 Hz over a range of spatial frequencies. Disabled readers were less sensitive than the controls at all spatial frequencies, with the differences between the groups increasing as spatial frequency increased. Both these findings are interpreted as supporting the hypothesis of a transient-system deficit in the visual systems of disabled readers.

Temporal Integration and Contrast Sensitivity in Foveal and Peripheral Vision

Perception ◽  
1984 ◽  
Vol 13 (6) ◽  
pp. 665-674 ◽  
Author(s):  
Jyrki Rovamo ◽  
Lea Leinonen ◽  
Pentti Laurinen ◽  
Veijo Virsu
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Peripheral Vision ◽  
Temporal Integration ◽  
Photopic Vision ◽  
Spatiotemporal Information ◽  
Spatial Frequencies ◽  
Primary Determinant ◽  
Integration Improvement

Spatial contrast sensitivity functions and temporal integration functions for gratings with dark surrounds were measured at various eccentricities in photopic vision. Contrast sensitivity decreased with increasing eccentricity at all exposure durations and spatial frequencies tested. The decrease was faster at high than at low spatial frequencies, but similar at different exposure durations. When cortically similar stimulus conditions were produced at different eccentricities by M-scaling, contrast sensitivity became independent of visual field location at all exposure durations tested. The results support the view that in photopic vision spatiotemporal information processing is qualitatively similar across the visual field, and that quantitative differences result from retinotopical differences in ganglion cell sampling. For gratings of constant retinal area temporal integration (improvement of contrast sensitivity with increasing exposure duration) was more extensive at high than at low retinal spatial frequencies but independent of cortical spatial frequency and eccentricity. For M-scaled gratings temporal integration was more extensive at high than at low cortical spatial frequencies but independent of retinal spatial frequency and eccentricity. The results suggest that the primary determinant of temporal integration is not spatial frequency but grating value that is calculated as AF2 square cycles (cycle2), where A is grating area and F spatial frequency.

Red-green vs. blue-yellow spatio-temporal contrast sensitivity across the visual field

2011 ◽  
Vol 58 (19-20) ◽  
pp. 1736-1748 ◽  
Author(s):  
M.A. Díez-Ajenjo ◽  
P. Capilla ◽  
M.J. Luque
Keyword(s):  
Visual Field ◽  
Contrast Sensitivity ◽  
Temporal Contrast ◽  
Spatio Temporal
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