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Relationship of visual work productivity and indicators of functional state of visual system in Pcu.

INTRODUCTION

Scientific and practical aspects of health protection in PC users include several directions: physiology and hygienic monitoring, work productivity and functional state monitoring, estimation of adaptation processes, monitoring of the rehabilitation period. One of the actual and at the same time not enough_investigated subjects under consideration's the relationship of functional state and work productivity in PC users [1, 2]. The analysis of data shows that among the applied physiology publications in our country only a few are devoted to the health protection of office workers. At the same time the level of work intensity in office workers depending on their activities, social status, qualification changes from 3.3 to 3.1 classes, which corresponds to the level of stress in personal decision making in difficult situations, sensor load and visual strain [3]. Besides stress factors influencing health and work productivity of PC users, visual loads are of great importance. From the above mentioned it is important to further investigate physiological mechanisms of visual fatigue and working productivity in PC users.

MATERIALS AND METHODS

PC users--office workers (men=12, middle age- 32, women =26, middle age-43) were examined in two stages. Firstly, for quantitative estimation of subjective components of chronic visual fatigue in PC users anamnestic questionnaire monitoring was carried out in the following succession: nature of complaints, intensity of complaints, duration of complaints. At the second stage ophthalmological status (acuity of vision and refraction) was estimated as well as functional (critical flicker fusion frequency -CFFF) electrophysiological (electrosensitivity threshold -EST; electrolabilityEL), phychophysiological (channel capacity- CC, visual information volume -VIV, visual information speed -VIS, efficiency of visual information analysis -EVIA) investigations were carried out [4, 5]. They were carried out in standard laboratory conditions according to the generally accepted methods in conformity with the corresponding ethical requirements. In data analysis the rank correlative analysis was carried out and the estimation of reliability by Student's t-criteria.

RESULTS AND DISCUSSION

According to the data of questionnaire anamnestic research asthenopic complaints were presented by 71,3% PC users. The nature, intensity and duration of visual discomfort testified to the predominance of "eye" components of computer visual syndrome (CVS), conjunctiva irritation symptoms prevailing. According to the results of anamnestic monitoring all testees were divided into two equal groups: group A- with strongly expressed discomfort, group B--with weakly expressed discomfort.

Table 1 shows the results of research of functional state of visual system and work productivity in PC users with strongly and weakly expressed complaints of visual fatigue.

Special attention is drawn to the deviation of all investigated functional parameters of visual system from indicators accepted as the standard in both groups. This testifies to the fact that all stages of visual analyzer from retina (CFFF indicators) to visual cortex (EST, EL, CFFF) are involved in the process regardless of the expression of subjective components of CVS.

Data analysis showed that intergroup differences are valid only by EL indicator in the group with weakly expressed complaints, 63,68+5,24 (OD) and 66,42+5,18 (OS) and in the group with expressed complaints 47,95+3,41(OD) (p<0,01) whereas the other functional indicators and parameters of visual work productivity don't reach valid differences.

In group B, EL values are at the top standard border in comparison with other functional indicators which are considerably higher with respect to the standard. This states about the intensification of the process of excitement in the group with weakly expressed complaints. It allows to believe that in group B more expressed changes in neuronal network of visual analyzer take place.

In this connection, it is appropriate to note that in the neuroophthalmological diagnostics EL indicator is one of the most sensitive [6], and it reflects morphofunctional state of proximal layers of retina and optical pathways.

To verify the character of relationship between functional state of visual system and visual work productivity in PC users with different degrees of complaints of visual fatigue, the correlative analyses was carried out (table 2, 3).

In both groups, independently of expressed complaints negative moderate correlation between CFFF from the one hand and CC (r=-40 when p<0,05) and VIP (-0,38 when p<0,05) from the other was revealed. Negative relation between critical flicker fusion frequency and such parameters of visual perception as channel capacity of visual system and visual information processing may seem to be paradoxical because according to the canon of sensor physiology, the higher is the frequency characteristics of the communication channel, the higher its channel capacity [7].

Dealing with our results one can admit that this dependence is typical for good functional state of visual analyzer and when fatigue develops dissociation arises between parameters by the type of paradoxical reaction at the initial stages of functional breakdown of higher nervous activities. The most complicated situation of correlative relation is observed in dividing the examined into groups by the intensity of complaints. So in the group with weak asthenopic complaints (table 2) valid relation are revealed between functional CFFF,EST,EL indicators on the one hand and CC,VIV,VIS,EVIA on the other. Moreover, positive relations are observed between CFFF and EST data. There is strong relationship between psycophysiological CC and VIV indicators. Positive correlative relationship has been found between VIS and EVIA.

In the group with strongly expressed asthenopic complaints another type of correlative relation is observed. A number of correlative relationship decreases considerably, relationship is seen only between the indicators of visual acuity and EVIA. Moderate relationship is observed between CFFF and EAVI indicators and strong, positive correlative relationship is observed between VIS and VIV.

As it was mentioned above the dependence of visual work productivity on the functional state of visual system in PC users, in general sense, can be explained from the viewpoint of functional disorders of higher nervous activity, its paradoxical phase. But such explanation can't be satisfactory enough from the viewpoint of modern physiology. We have already shown [8, 9] the reaction of mechanisms performing the analysis and transmission of visual information to extreme impacts. We believe that the same mechanisms with the rising activating system form the basis of development of physiological processes of visual fatigue with dissociation of functional state of visual system and visual work productivity in PC. This opinion is in agreement with activated and resources models of selective attention, according to which definite, limited resources are required for analysis and selection of signals.

The tendency to rising of EST with a certain decrease of channel capacity testifies to activation of inhibitory processes in visual system. This is confirmed by the data of electrophysiological research [10] which reveal dynamic increase of beta activity in the frontal, central and occipital regions of the cerebral cortex. The authors believe that the testees make a lot of efforts to support necessary efficiency in visual information processing .

Thus, the obtained data confirm information about inverse relationship between functional state of visual analyzer and visual work productivity in developing visual fatigue in PC users. Further research is required to verify the mechanisms of this dependence.

ARTICLE INFO

Article history:

Received 25 March 2014

Received in revised form 20 April 2014

Accepted 15 May 2014

Available online 5 June 2014

REFERENCES

[1] Hsieh, Y.H., C.J. Lin, H.C. Chen, 2007. Effect of vibration on visual display terminal work performance: Percept Mot Skills, 105(3 Pt 2): 1055-8.

[2] Blehm, C., S. Vishnu and A. Khattak, 2005. Computer Vision Syndrome: A Review. Surv. Ophthalmol, 50

(3): 253-62.

[3] Brasche, S., M. Bullinger, A. Petrovitch, 2005. Self-reported eye symptoms and related diagnostic findings--comparison of risk factor profiles: Indoor Air.,15(10): 56-64.

[4] Chiuhsiang, J.L. Feng Wen-Yang, 2008. Effects of VDT Workstation Lighting Conditions on Operator Visual Workload: Industrial Health, 46: 105-111.

[5] Budnevskii, A.V, I.S. Afendulova, I.A. Zakharova, 2009 Computer technologies in diagnostics of sensor visual fatigue: Applied information aspects of medicine, 1(V12): 38-44.

[6] Bogoslovskii, A.I. and N.A. Kovalchuk, 1980. Electrical phosphen in ophthalmology. Ophthalmological electrodiagnostics, Research works MHRIED.-M, pp: 150-166.

[7] Glezer, VD. and I.I. Tsukkerman, 1961. Information and vision. Izdatelstvo USSR AS, pp: 184.

[8] Fenga, C., R. Di Pietro, P. Fenga, C. Di Nola and C. Spinella, 2007. Asthenopia in VDT users: our experience. G Ital Med Lav Ergon, 29 (3 Suppl): 500-501.

[9] Khalfina, R.R., R. Ahmadeev, T. Timchenko and A. Minullin, 2014. Phychophisiological regularities of fatigue and recreation of visual system in PC users. St. Peterburg: SPC PSN.

[10] Lavie, N. and A. Hirst, 2004. Theory of Selective Attention and Cognitive Control. Journal of Experimental Psychology: General, 133(3): 339-354.

(1) Regina Robertovna Khalfina Ain E.B., (2) Tatyana Valentinovna Timchenko

(1) Fsosfee "The Law Institute Of Mha Of Russia"

(2) Muksinova st., 450099 Ufa FSBEE "The Bashkir State Pedagogical University Named After M.Akmulla 3a, Oktyabrskaya Revolutsii st., 450000 Ufa

Corresponding Author: Regina Robertovna Khalfina Ain E.B., Fsosfee "The Law Institute Of Mha Of Russia
Table 1: Functional state of visual system and visual work
productivity in PC users with different stages of expressed
complaints of visual fatigue.

                                     Weakl y expressed

                             OD                     OS

Functional indicators

Acuity of vision     0,49 [+ or -] 0,10     0,59 [+ or -] 0,10
Refraction          -0,43 [+ or -] 0,38     -0,28 [+ or -] 0,41
CFFF, Hr            36,53 [+ or -] 1,90     36,97 [+ or -] 1,81
EST, pA             114,47 [+ or -] 9,96   116,58 [+ or -] 10,74
EL, Hr              47,95 [+ or -] 3,41     53,21 [+ or -] 3,49

                                  Strongly expressed

                              OD                       OS

Functional indicators

Acuity of vision     0,70 [+ or -] 0,062       0,73 [+ or -] 0,069
Refraction           -1,75 [+ or -] 0,60      -1,55 [+ or -] 0,51 *
CFFF, Hr            33,87 [+ or -] 1,81 *     35,05 [+ or -] 1,82 *
EST, pA             125,47 [+ or -] 17,88 *  127,89 [+ or -] 15,17 *
EL, Hr              63,68 [+ or -] 5,24 *     66,42 [+ or -] 5,18 *

                    Standard

Functional indicators

Acuity of vision       1
Refraction
CFFF, Hr            37-55 Hr
EST, pA             50-80 pA
EL, Hr              30-40 Hr

Work productivity indicators

VIP ** (bit)         60,23 [+ or -] 5,11     61,42 [+ or -] 3,72
VIS ** (bit/sec)      0,68 [+ or -] 0,07     0,63 [+ or -] 0,07
CC ** (bit/sec)       1,09 [+ or -] 0,08    0,956 [+ or -] 0,08 *
EVIA ** (nom.unit)    0,48 [+ or -] 0,07    0,58 [+ or -] 0,05 *

Work productivity indicators

VIP ** (bit)
VIS ** (bit/sec)
CC ** (bit/sec)       1,08-1,42 bit/sec
EVIA ** (nom.unit)

Note: * validity of differences when p<0,05; ** values, obtained
from individuals of the same age which didn't use PC are
accepted as the standard

Table 2: Intergroup correlative analysis in the group with
weakly expressed asthenopic complaints.

                Correlation
Indicators         degree      Validity

CFFF     EST        0,46         <0,05
         CC        -0,66         <0,01
         VIV       -0,63         <0,01
EST      VIV       -0,63         <0,01
         VIS       -0,58         <0,05
EL       VIS       -0,56         <0,05
CC       VIV        0,72         <0,01
VIS     EVIA        0,66         <0,01

Table 3: Intergroup correlative analysis in the group
with expressed asthenopic complaints.

         Indicators         Correlation degree   Validity

Acuity of vision    EVIA           0,47           <0,05
CFFF                EVIA           0,47           <0,05
VIS                  VIV           0,69           <0,01
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Article Details
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Author:Khalfina Ain E.B., Regina Robertovna; Timchenko, Tatyana Valentinovna
Publication:Advances in Environmental Biology
Article Type:Report
Date:Jun 1, 2014
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