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ORIGINAL ARTICLE
Year : 2017  |  Volume : 4  |  Issue : 4  |  Page : 114-119

Assessment of the effect of academic examination stress on binocular vision functions among secondary school-aged children


Department of Binocular Vision, Faculty of Optometry and Visual Sciences, Alneelain University, Khartoum, Sudan

Date of Web Publication7-Jun-2019

Correspondence Address:
Dr. Amani Ahmed Elsiddig
Department of Binocular Vision, Faculty of Optometry and Visual Sciences, Alneelain University, Khartoum
Sudan
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DOI: 10.4103/bijo.bijo_16_18

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  Abstract 


Background: Binocular single vision involves the simultaneous use of both eyes with bifoveal fixation, and this process helps individuals to use their both eyes for reading, writing, and other near activities; the stress on this system could lead to ocular complaints and affect the near task for the school-aged children.
Aim: The aim of this study was to assess the effect of academic examination stress on binocular vision functions among secondary school-aged children in Khartoum State of Sudan.
Materials and Methods: This is an experimental study of 148 secondary school-aged children, selected randomly from Alfath Secondary School, and their ages ranged from 13 to 17 years with a mean age of 14.6 ± 1.13 years. Investigation was performed before and after the academic examinations in 2017. The clinical examinations include visual acuity measurements using Snellen vision testing chart, refraction using autorefractometer, dissociated near phoria by Maddox Wing, associated near phoria by Mallet Fixation Disparity Test, amplitude of accommodation and near point of convergence (NPC) measured by R.A.F rule, and near positive fusional vergence (PFV) and near negative fusional vergence by prism bar. All these investigations were done before 15 days of academic examinations and on the day after the students finished their academic examinations.
Results: The findings indicated that most of the students (62.8%) before the academic examinations reported that they were free from any ocular complaints, whereas 37.2% had ocular symptoms. After stress due to examinations, the percentage of students who had ocular complaints increased to 71.6, whereas those free of ocular complaints decreased to 28.4. The mean of amplitude of accommodation before taken the examinations was 9.81 ± 2.16, and after the examination, the mean of amplitude of accommodation decreased to 8.77 ± 1.97 (P < 0.001). Nearly 54.7% of the participants had normal NPC before the academic examinations, and after the examinations, those who had normal NPC decreased to 46.4% (P < 0.001). Only 29% of the students had associated heterophoria before the stress of examinations, and after the examinations, the percentage of students with associated heterophoria increased to 56.5 (P < 0.001). Almost 40.5% of the students presented with normal PFV at near fixation, and after the stress, only 29.1% had normal PFV at near fixation. However, more than half of the students (59.5%) had weak PFV for near fixation before the examinations, and after the examination, they increased to 70.9% (P < 0.001).
Conclusion: The academic examination stress had a major effect on binocular vision functions, result in decompensated heterophoria, as well as decline in amplitude of accommodation, and NPC. Thus, comprehensive eye examination including binocular vision function assessment should be made annual for school-aged children.

Keywords: Associated phoria, convergence insufficiency, stress binocular vision functions, weak positive fusional vergence


How to cite this article:
Elsiddig AA, Alrasheed SH. Assessment of the effect of academic examination stress on binocular vision functions among secondary school-aged children. Albasar Int J Ophthalmol 2017;4:114-9

How to cite this URL:
Elsiddig AA, Alrasheed SH. Assessment of the effect of academic examination stress on binocular vision functions among secondary school-aged children. Albasar Int J Ophthalmol [serial online] 2017 [cited 2019 Oct 14];4:114-9. Available from: http://www.bijojournal.org/text.asp?2017/4/4/114/259772




  Introduction Top


The human eyeball moves smoothly by six extraocular muscles, consisting of four recti and two oblique muscles which arise from the wall of the orbit and insert into the sclera.[1] Binocular single vision is defined as coordinated use of two eyes to produce a single mental impression.[2],[3] Normal binocular vision without symptoms depends on three factors: the anatomy of visual apparatus, the motor system that coordinates the movement of the eyes, and sensory system through which the brain receives and integrates the two monocular signals. Anomalies in any of these can cause difficulties in binocular vision or even make it impossible.[2]

There are three grades of binocular vision. The first level is simultaneous perception, defined as the ability to see two objects at one time. The second level is fusion, which is divided in two types: sensory fusion is the neural process of synthesizing or integrating the monocular percepts into single binocular percept and motor fusion, which refers to moving the eyes result in the object of regard falling on corresponding retinal area. The last and advance level stereopsis is the ability to perceive depth when the eye is presented with a slightly dissimilar image of the same object.[4],[5] Orthophoria is defined as a binocular fixation in which the lines of vision of the two eyes meet at the object and considered as a normal condition of balance of the ocular muscles of the two eyes.[6] Heterophoria is a binocular condition in which the directions that the eyes are pointing at rest position, when not performing binocular fusion, are not the same as each other.[7] Decompensated heterophoria is usually detected by the presence of certain symptoms including asthenopia, blurring, and, sometimes, doubling, and these condition have serious effect on near activist.[8]

Alrasheed et al., 2016,[9] reported that the prevalence of heterophoria and heterotropia among school-aged children was 51.1% at near fixation and 5.7% at distance fixation; they indicated that most of the children (46.6%) had exophoria at near fixation and only 0.3% had tropia. In another study, Hassan et al.[10] in 2018 revealed that the prevalence of convergence insufficiency (CI) among Sudanese secondary schoolchildren was 7.8%. Previous studies[11],[12],[13] indicated that the stress on binocular vision could lead to decreased binocular vision functions which in turn result in increased ocular complaints. These may have serious effects on near task for school-aged children such as writing, reading, and concentration on near task and could influence the academic achievements of the students. Therefore, this study was conducted to assess the effect of the academic examination stress on binocular vision functions among secondary school-aged children in Khartoum State of Sudan.


  Materials and Methods Top


This was an experimental study to assess the effect of academic examination stress on binocular vision functions among secondary school students in Alfath Secondary School at Khartoum State of Sudan, and the study was carried out from September 2017 to October 2017. One hundred and forty-eight secondary school students, aged 13–17 years, who were attending the school on the examination days, and free from manifest squint, ocular, and systemic diseases, and accepted to participate in this work, were included in the study. Students who had undertaken academic examinations were selected randomly from Alfath Secondary School at Khartoum State. After collecting the demographic information of all the participants, first, the details of ocular symptoms were obtained. Then, clinical investigations were performed which included presenting distance vision and visual acuity (VA) which was assessed using Snellen chart at a standard range of 6-m distance. Objective refraction was performed by an autorefractometer. Then, subjective refraction and VA were performed. Near-dissociated heterophoria was measured by Maddox Wing (Keeler instruments Inc. for Maddox Wing Test; 301-p-1022 Maddox Wing Test; US) test, Near point of convergence (NPC) and amplitude of accommodation was measured using R.A.F rule (Royal Areal Force; Good-Lite, 1155 Jansen Farm Dr. Elgin, IL 60123, USA). The near-associated heterophoria was measured by Mallet Unit Fixation Disparity Test, and finally, positive fusional vergence (PFV) and negative fusional vergence (NFV) were measured by prism bars. All these investigations were done before 15 days of academic examinations and on the day after the students finished their academic examination.

Data forms were reviewed for accuracy and completeness before data collection. The data for each student were analyzed using Statistical Package for the Social Sciences (manufactured by IBM SPSS Inc. PASW Statistics for Windows, Version 22.0; 2011. Chicago: SPSS Inc., IL, USA). Standard deviation (SD) and percentages were used to determine the descriptive statistics; paired sample tests were used to compare between tests variable. Chi-square test was used to determine statistical significance. For all statistical determinations, the significance level was established at P = 0.05.


  Results Top


A total of 148 participants (256 eyes) were examined in this study from Alfath Secondary School, and all the participants who were included in this study were exposed to stress during academic examinations. The distribution of participants according to the gender and age was as follows: equal gender distribution, i.e., Males representing 74 (50%) and female representing 74 (50%), their ages ranged between 12 and 17 years, with a mean of 14.6 ± 1.13 years.

Corrected and uncorrected visual acuity of the participants

Eyes of the vast majority of school-aged children (225, 76%) had normal VA and the remaining children's eyes (71, 24%) had visual impairment. After correction, the number of eyes with normal VA increased to 291 (98.3%) and only 5 eyes (1.7%) remained with visual impairment, as shown in [Table 1].
Table 1: Corrected and uncorrected visual acuity of the participants

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Distribution of refractive errors among participants

Half (50%) of the students' eyes in this study were emmetropic. The distributions of refractive errors among the participants with astigmatism, myopia, and hypermetropia were 29.4%, 19.9%, and 0.7%, respectively, as shown in [Table 2].
Table 2: Distribution of refractive errors among the participants

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Ocular complaints among school-aged children before and after the stress of academic examinations

Most of the students (62.8%) before taking the academic examinations reported that they were free from any ocular complaints, whereas 37.2% had ocular symptoms. After stress of the examinations, the percentage of students who had ocular complaints increased to 71.6, whereas percentage of students who were free of ocular complaints decreased to 28.4; the relation between academic stress and ocular complaint was statistically significant (P < 0.001), as shown in [Table 3].
Table 3: Distribution of ocular symptoms among school-aged children before and after the stress of academic examination

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Amplitude of accommodation before and after the examination stress

The mean and SD of amplitude of accommodation of the school-aged children before taking the examinations was 9.81 ± 2.16, and after the examinations, the mean and SD of amplitude of accommodation decreased to 8.77 ± 1.97. Paired sample t-test was used to compare between accommodations before and after stress of academic examinations, the result showed a significant difference (t = 9.9, df = 147, P < 0.001).

Near point of convergence among participants before and after the examination stress

More than half of the participants (54.7%) had normal NPC before the academic examinations, and after the examinations, the percentage of students who had normal NPC decreased to 46.4. However, 40.5% of students had Convergence Insufficiency (CI) before the examinations after the end of examinations the students had CI increased to 53.4%. The paired sample t-test was used to compare between NPC before and after stress of examinations, the result of which showed a significant difference (t = 6.5, df = 147, P < 0.001), as illustrated in [Table 4].
Table 4: Near point of convergence among the participants before and after the examination stress

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Heterophoria for near fixation before and after examination stress

Nearly 13.7% of the students presented with normal muscle balance (orthophoria) before the stress of academic examinations, and after the stress, only 23% of the students were orthophoric. Almost 15.5% of the students had moderate degree of exophoria, and after the stress, about 18.9% of the students had moderate degree of exophoria. With regards to esophoria it less prevalent among the students then exophoria, before the stress of examination 21 (14.2%) had esophoria after the stress the students with esophoria decreased to 18 (12.2%), as shown in [Table 5].
Table 5: Distribution of heterophoria for near fixation among the participants before and after the stress

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Associated heterophoria before and after the stress of academic examinations

The Mallet Unit Fixation Disparity Test revealed the following results: almost 71.0% of the students before taking their academic examinations presented without associated heterophoria. However, 29% of the students had associated heterophoria before the stress of examinations, of those 23% had prism base-in associated phoria and only 6% had prism base-out associated phoria. After the examinations, the percentage of students without associated heterophoria reduced from 70.0 to 56.5, and the percentage of students with associated heterophoria increased from 29 to 43.5. The percentage of students who had prism base-in associated phoria increased from 23 to 35.4, more than the percentage of students who had base-out associated heterophoria, i.e., from 6 to 8.2. The sample t-test was used to compare between associated heterophoria before and after stress, the result showed a significant difference (t = 3.7, df = 147, P < 0.001).

Positive fusional vergence among participants before and after the stress

Nearly 40.5% of the students presenting with normal Positive Fusional vergence (PFV) at near fixation, after the stress of examination there is dramatically decreased of PFV at near 29.1%, this associated with increased in ocular complaints for near. However, more than half of students (59.5%) had weak PFV for near before the examinations after the examinations those increased to 70.9%. The paired sample t-test was used to compare between positive fusion at near fixation before and after stress of examinations; the result showed a significant difference (t = 3.7, df = 147, P < 0.001), as illustrated in [Table 6].
Table 6: Distribution of positive fusional reserve before and after stress

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Negative fusional vergence among participants before and after the stress

Nearly 42.6% of the participants presented with normal NFV reserve, and 57.4% had weak NFV, and after the stress, the percentage of students with normal NFV reserve increased to 52 and that of those who had weak negative NFV reserve decreased to 48. The paired sample t-test was used to compare between negative fusion reserve before and after stress of examination; the result showed a significant difference (t = 3.0, df = 147, P = 0.002), as shown in [Table 7].
Table 7: Distribution of negative fusional reserve before and after the stress

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  Discussion Top


Excessive use of the eyes could lead to stress on visual functions and could result in ocular complaints, particularly among school-aged children during the examinations period, and eventually may have an effect on the children's academic performances. The current study was conducted to assess the effect of the academic examination stress on binocular vision functions among secondary school-aged children in Khartoum State of Sudan. Most of the students in this study before taking the academic examination were asymptomatic, whereas after stress of the examinations, the vast majority of the students became symptomatic, which was statistically significant (P = 0.001). This could be due to the effect of the stress on binocular vision functions, lead to change in degree of the heterophoria at near result in ocular complaints. In a study, Demirkilinc Biler et al. in 2017[13] indicated that the stress on the convergence and divergence causes decrease of the stereoacuity, and this has an effect on the intermittent ocular deviation among the participants. Yekta et al.[14] indicated that the stress on binocular vision is accompanied by visual symptoms. Our study revealed that the mean and SD of the amplitude of the accommodation of the participants decreased from 9.81 ± 2.16 to 8.77 ± 1.97, before and after the examinations stress, which was statistically significant (P < 0.001). The examination stress may have effect on ciliary muscle activity and result there is change in amplitude of accommodation. In this study, more than half of the participants (54.7%) had normal NPC before the academic examinations, and after the examinations, the percentage of students those who had normal NPC decreased to 46.4. However, 40.5% of students had CI before the examination, after the end of examinations the students with CI increased to 53.4%. The change in NPC before and after the examination was statistically significant (P < 0.001). This agreed with the study conducted by Yi et al. in 2015[15], in which they reported that 30-min reading stress changed NPC from 9.58 cm to 11.25 cm.

The near phoria test revealed that 15.5% of the children had a moderate degree of exophoria before taking their examinations, and after the stress of the academic examinations, the percentage of the children with a moderate degree of exophoria increased to 18.9. With regard to esophoria it less common among the children then exophoria, before the stress of examinations, 21 (14.2%) had esophoria after the stress the students with esophoria decreased to 18 (12.2%). This disagreed with the study conducted by Yekta et al.,[14] to assess binocular vision at the beginning of normal working day and same procedure in afternoon which induced several hours of close work, it was found that dissociated heterophoria increased after the stress of working.

In this study, most of the students (71.0%) before taken their academic examinations presented without associated heterophoria and only 29% of the students had associated heterophoria. However, after the stress of examinations, the percentage of students without associated heterophoria reduced to 56.5, and percentage of students with associated heterophoria increased to 43.5. The students who has prism base-in associated phoria their percentage increased more than the students who had base-out associated heterophoria, which was statistically significant (P < 0.001). Our study is in line with the study conducted by Garzia and Dyer,[16] in which they revealed that the stress of reading more than 25 min had significant effect on near-associated heterophoria. The current study revealed that 40.5% of the students presented with normal PFV at near fixation, and after the stress of examination, there was a dramatic decrease to 29.1%. When compared between PFV at near fixation before and after stress of examinations, the result showed a significant difference (P < 0.001). This result agreed with the study by Yi et al. 2015,[15] in which they indicated that 30 min of reading stress leads to decrease in PFV from 17.22Δ to 15.56Δ. With regard to NFV, 42.6% of the participants presented with normal NFV, and 57.4 had weak NFV, and after the stress, the percentage of students with normal NFV increased to 52 and the percentage of students who had weak NFV decreased to 48, which was statistically significant (P = 0.002).


  Conclusion Top


To our knowledge, no similar study has been conducted in Sudan to assess the effect of academic examination stress on binocular vision functions. The study concluded that the academic examination stress had a major effect on binocular functions, could lead to decompensating heterophoria as well as decline in amplitude of accommodation, and NPC. Thus, comprehensive eye examination including binocular function assessment should be made annual for school-aged children.

Acknowledgment

After the Almighty Allah, the authors would like to express their sincere thanks and gratitude to all the teachers, students, and staffs for their great help in data collection and completing this study. They would also like to thank all the people who participated in this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Brooks SE. Securing extraocular muscles in strabismus surgery: Laboratory analysis of biomechanical parameters related to the suture. J AAPOS 2017;21:457-90.  Back to cited text no. 1
    
2.
Evans BJ. Pickwell's Binocular Vision Anomalies Investigation and Treatment. 5th ed. London: Elsevier Health Sciences; 2007.  Back to cited text no. 2
    
3.
Collewijn H, Erkelens CJ, Steinman RM. Binocular co-ordination of human horizontal saccadic eye movements. J Physiol 1988;404:157-82.  Back to cited text no. 3
    
4.
Cooper J, Cooper R, Press L. What is Strabismus. Available from: https://www.aao.org/eye-health/diseases/what-is-strabismus. [Last accessed on 2016 Jul 10].  Back to cited text no. 4
    
5.
Mizrak A, Erbagci I, Arici T, Ozcan I, Ganidagli S, Tatar G, et al. Ketamine versus propofol for strabismus surgery in children. Clin Ophthalmol 2010;4:673-9.  Back to cited text no. 5
    
6.
Fisher DF, Monty RA, Senders JW. Eye Movements and the Higher Psychological Functions. California: Routledge; 2017.  Back to cited text no. 6
    
7.
Wajuihian SO. Prevalence of heterophoria and its association with near fusional vergence ranges and refractive errors. Afr Vis Eye Health 2018;77:1-9.  Back to cited text no. 7
    
8.
Shin HS, Park SC, Park CM. Relationship between accommodative and vergence dysfunctions and academic achievement for primary school children. Ophthalmic Physiol Opt 2009;29:615-24.  Back to cited text no. 8
    
9.
Alrasheed SH, Naidoo KS, Clarke-Farr PC. Prevalence of visual impairment and refractive error in school-aged children in South Darfur state of Sudan. Afr Vis Eye Health 2016;75:1-9.  Back to cited text no. 9
    
10.
Hassan LI, Ibrahim SM, Abdu M, MohamedSharif A. Prevalence of convergence insufficiency among secondary school students in Khartoum, Sudan. Oman J Ophthalmol 2018;11:129-33.  Back to cited text no. 10
[PUBMED]  [Full text]  
11.
Yekta AA, Pickwell LD, Jenkins TC. Binocular vision without visual stress. Optom Vis Sci 1989;66:815-7.  Back to cited text no. 11
    
12.
Pickwell D, Jenkins T, Yekta AA. The effect on fixation disparity and associated heterophoria of reading at an abnormally close distance. Ophthalmic Physiol Opt 1987;7:345-7.  Back to cited text no. 12
    
13.
Demirkilinc Biler E, Guven Yilmaz S, Kucukceran E, Uretmen O. The effect of convergence and divergence stress on near stereoacuity. Int Ophthalmol 2017;37:165-8.  Back to cited text no. 13
    
14.
Yekta AA, Jenkins T, Pickwell D. The clinical assessment of binocular vision before and after a working day. Ophthalmic Physiol Opt 1987;7:349-52.  Back to cited text no. 14
    
15.
Yi P, Helen Gabriel OD, Frantz KA. Effect of Near Work on Binocular Vision Measurements in Adults with Convergence Insufficiency; February 2015. p. 42-9.  Back to cited text no. 15
    
16.
Garzia RP, Dyer G. Effect of nearpoint stress on the horizontal forced vergence fixation disparity curve. Am J Optom Physiol Opt 1986;63:901-7.  Back to cited text no. 16
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

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