Effects Of Reading And Working On The Computer On Vision

Project and Seminar Material for Biology

Effects Of Reading And Working On The Computer On Vision


The objective is to determine if a person blinks less, and therefore vision worsens after reading and working on the computer.

Informed consent was obtained from 15 subjects, men and women ranging in age from 10 to 103. Structured questionnaires were administered to 100 computer users aged between 18 and 40 years. The study findings revealed that 40 respondents (40%) were aware of CVS and 27 (27%) of them had knowledge of the disorder. 74 (74%) of the respondents experienced at least one symptom of CVS. Headache and eyestrain were the most common symptom of CVS among the population.

The study also revealed that the internet (accounting for 50%) was the major source of information about CVS awareness. The study concluded that 27% knowledge level is too low and much emphasis is needed to educate the people at risk of CVS

Chapter One


Background to the study

When the first IBM personal computer was manufactured in 1981, the company did not envisage the possible potential health hazards the users may consequently experience (Mvungi, Mcharo, Mmbuji, Mgonja & Kitua 2009, p.69). Today, a condition known as Computer Vision Syndrome (CVS) is common to millions of computer users around the world. A syndrome is defined as a group of signs and/ or symptoms which occur together to produce a pattern typical of a particular disease (Pocket Medical Dictionary 1987, p.256). CVS is characterised by a complex group of eye and vision-related problems that result from prolonged computer use (Bali, Navin & Thakur 2007, p.290).

Nearly 60 million people suffer from CVS globally and a million new cases occur each year (Sen & Richardson 2007, p.45). Symptoms of CVS occur in approximately 75-90% of computer users (Anshel 2007, p.37). Studies conducted in Nigeria have shown that CVS may result in lowered productivity, increased error rate, reduced job satisfaction, impaired visual abilities and blurred distant vision (Chiemeke, Akhahowa & Ajayi 2007, p.1).

Mvungi et al (2009, p.73) also reported that most problems associated with the use of the computer can be largely attributed to improper use of computers and most importantly, insufficient knowledge about safe computer usage techniques and practices. Most CVS-related problems can be avoided by appropriate preventive measures, but the majority of computer users are not aware of CVS-related symptoms while some choose to ignore them (Divjak & Bischof 2009, p.350).

The research problem is derived from clinical practice. The case history records from a private eye clinic in Abuja, Nigeria show that one of the most common complaints by patients is eyestrain during computer use. The records also show that a large proportion (about 90%) of people with these complaints work with computer for prolonged hours (at least 4 hours daily) and were diagnosed to suffer from Computer Vision Syndrome. The research questions therefore include:

  1. How much do the computer users know about this disorder?
  2. What is the extent of CVS among computer users in the selected workplace?
  3. Will a good knowledge of CVS and its preventive measures reduce the number of patients seeking relief from computer-related stress?

Extensive literature search did not reveal any study that assessed the knowledge of computer users about CVS in Abuja, Nigeria, hence the rationale for this study. To successfully address this public health issue, there is a need to assess the knowledge of the people at risk, so that adequate measures can be developed.

There is sufficient evidence in the literature that a large number of computer users suffer from CVS (Ihemedu & Omolase 2010, p.49; Sen & Richardson 2007; Torrey 2003). In the USA more than 143 million Americans work on a computer each day with an estimated 90% suffering from computer eyestrain. Additionally, almost 90% of children in the USA work on a computer at home or in school every day (LFV [n.d.]; VCA 2007). Computer use in Nigeria has attained a significant patronage especially with the upsurge of information and communication technology systems as most organisations barely manage their businesses without it. However, poor publicity and utilisation of preventive measures have hampered the effectiveness of computers due to the overwhelming symptoms experienced by some users (Ihemedu & Omolase 2010, p.51). Awareness of visual problems from computer use has also been minimally stressed in most industrially developing countries like Nigeria (Chiemeke et al 2007).

CVS is caused by the eye and brain reacting differently to characters on the screen than they do printed characters. Characters on a computer screen lack the contrast or well defined edges that printed characters have. Because the colour intensity of digital characters diminishes around the edges, it is difficult for eyes to remain focused. Having to continuously refocusing on digital text fatigues the eyes and can lead to burning or tired eyes. CVS is marked by symptoms such as eyestrain, burning sensation, blurred vision, gritty sensation, headache and neck pain. Some computer users may experience continued reduced visual abilities such as blurred distant vision even after work (Chiemeke et al 2007). These symptoms may be aggravated by poor lighting, glare, improper work station set up and uncorrected refractive errors (Ihemedu & Omolase 2010, p.49; Torrey 2003). Though symptoms such as burning sensation and gritty sensation have been reported by people exposed to dusty environments, it is however not clear whether these symptoms occur to a greater extent in computer users than workers in other highly visually demanding occupations (Chiemeke et al 2007).

A study conducted by Chiemeke et al (2007) in Benin, Nigeria tested the respondents’ knowledge on computer ergonomics and preventive measures of CVS. Results from the study showed that only a small percentage (32%) of the respondents was aware of preventive measures for visual symptoms, while a minority (1%) had former ergonomics guidelines/ policies at their workplace. Similar studies in south-west Nigeria (Ihemedu & Omolase 2010) show that a large number of respondents were aware of various types of computer shields but only a few utilised the shields. Studies from other parts of Africa show that most problems associated with computer use are caused by insufficient knowledge about safe computer usage (Mvungi et al 2009, p.73).

CVS remains an underestimated and poorly understood issue at the workplace (Izquierdo, Garcia, Buxo & Izquierdo 2004, p.103). About 70% of computer workers worldwide report having vision problems and there is an alarming increases in the number of people affected (Blehm, Vishnu, Khattak, Mitra & Yee 2005). Not much is known about CVS among children in Africa who are also increasingly becoming regular computer users. Some researchers (Divjak & Bischof 2009, p.350; Mvungi et al 2009, p.69) explain that CVS can be avoided by suitable preventive actions but majority of the sufferers are ignorant of this. In this light, some eye care professionals have referred to CVS as the number one occupational epidemic of the 21st century (Graney [n.d.]; Torrey 2003).

Statement of Problem

Mounting evidence shows that CVS can significantly harm workplace productivity, as it places an unusual strain on the human physical well-being thereby reducing the quality of life (Torrey 2003). Studies by Izquierdo et al (2004), Chiemeke et al (2007), Divjak & Bischof (2009) have shown a direct correlation between proper vision correction and the time required for a computer worker to complete a task; and that productivity is reduced even more among computer users who were unaware that they had vision problems. CVS is therefore a significant public health problem as it affects computer users from all walks of life (Torrey 2003).

Current management of CVS in Nigeria makes little emphasis on educating computer users. It is therefore imperative to assess the knowledge about CVS and level of awareness of its preventive measures among computer users in order to develop strategic interventions to reduce the effects of CVS among computer users and identify areas in which educators will concentrate their efforts.

Objective of the Study

The main purpose of the study is to assess effects of reading and working on the computer on vision specifically the study aims to:

  1. To explore the level of knowledge and awareness about CVS among computer users.
  2. To determine the extent of CVS by assessing the visual symptoms among the study population.

Significance of the Study

The study will contribute as evidence-based information to the little literature available on CVS in Nigeria. Information about CVS knowledge will help employers and other stakeholders to develop strategies that will be used to reduce the effects of CVS in the selected population. The strategies, if eventually applied would help reduce the loss of productivity in the workplace and the associated visual discomfort.

Training institutions and health educators will find the information useful for developing and revising training curricula that will enhance knowledge and level of awareness of CVS among computer users. This will contribute to the reduction in the occurrence and effects of CVS in Nigeria.

Research Question

  1. What is the level of knowledge and awareness about CVS among computer users?
  2. What is the extent of CVS by assessing the visual symptoms among the study population?

Scope of the Study

This study on the effects of reading and working on the computer on vision will focus on the computer vision syndrome in workplace in Abuja. In this study the workplace refers to the Securities and Exchange Commission (SEC) headquarters in Abuja, Nigeria

Limitations of the Study

Depth or accuracy of the knowledge of CVS may not be ascertained due to the instrument used (structured questionnaire). Therefore, respondents who indicate familiarity with CVS may only have a shallow knowledge of the disorder.

Generalisability of the findings may be limited, since only one institution will be included in the study.

Definitions of Terms


Conceptual Definition:

The fact or condition of knowing something with familiarity gained through experience or association (Merriam-Webster 2011).

Operational Definition:

Knowledge in the study will be defined as having some understanding of CVS.


Conceptual Definition:

Knowing that something exists (Oxford advanced learner’s dictionary 2006, p.88).

Operational Definition:

Awareness in this study will be defined as having heard of CVS.

Computer Vision Syndrome

Conceptual Definition:

A complex group of eye and vision-related problems that result from prolonged computer use (Bali et al 2007, p.290).

Operational Definition:

Eyestrain, blurred vision and headache that occur as a result of computer use (Chiemeke et al 2007).

Conceptual Definition:

Office, factory or place where people work (Oxford advanced learner’s dictionary 2006, p.1698).

Chapter Five

Findings, Conclusions and Recommendations

5.1 Introduction

CVS is a condition that affects millions of people globally (Sen & Richardson 2007, p.45). With advances in technology and dependency on information technology, the computer has become a common tool in schools, colleges, universities and workplaces. As such, CVS is becoming a public health concern. Unfortunately, CVS has not been studied extensively in Nigeria and other developing countries. This study was carried out to explore the level of knowledge about CVS among employees of the SEC in Abuja, Nigeria.

This chapter discusses the findings and limitations of the study and makes recommendations for practice, education and research.

5.2 Summary of Findings

A structured questionnaire was used in this study to collect data. Fifty four males (n=54) and forty six (n=46) females were recruited in this study. The respondents were mostly young working class with age ranging between 21 and 39 years. All respondents that participated in this study were literates with the majority (69%) having basic university degrees, 5% had secondary education, 20% had master degree and 6% had PhD. The majority of the respondents (73%) had little or no knowledge of CVS. Of the forty respondents who indicated being aware of CVS, only 27 have the knowledge of CVS. This means only 27% of the 100 respondents involved in the study had knowledge of CVS.

Seventy four percent (74%) of the respondents experienced at least one symptom of CVS. 25% did not experience any symptom of CVS. The CVS symptoms most experienced by respondents are headache (30.94%) and eyestrain (30.94%). Others are double vision (12.95%), watery eyes (10.79%), blur vision (10.07%) and redness (4.31%).
Sufficient knowledge about CVS and its preventive measures would help reduce the incidence in a population.

Extensive literature search did not reveal any publication on knowledge of CVS, thus making comparison with other results difficult. Studies conducted by Chiemeke et al (2007) reported that only 32% of respondents were aware of preventive measures for computer-related visual symptoms. Considering the fact that all respondents in this study are computer users and a majority are well educated, a CVS knowledge level of 27% would be considered inadequate. From the multiple choice questions, 60% of respondents indicated they are not aware of CVS, 2% of the respondents believe CVS is tiredness during computer use, 1% believe it means wearing glasses while using the computer, 10% indicated they had heard of CVS but do not know the meaning.

In this study, the knowledge of CVS increases with increasing age, with a strong positive correlation of 0.97. CVS knowledge was independent of gender as there was no significant difference in CVS knowledge between males and females. The analysis of the relationship between CVS and level of education was in this study restricted to respondents with basic university degrees and master/ PhD. The study revealed no statistical significant difference in CVS knowledge of the educational levels. However, respondents with master and PhD degrees had higher level of CVS knowledge (45% and 33% respectively) than the other groups. Respondents with master/ PhD degrees may be more research-oriented, thereby making them more knowledgeable about CVS.

The study also revealed that respondents who had visited an eye clinic for consultation with a doctor had more CVS knowledge than those who had not. This is an expected finding because respondents who had previous eye examination may have more potential for exposure to information about eye disorders from a doctor which might have prompted them to conduct personal search for information on CVS (Onunkwor 2011).

The findings from this study indicated that eyestrain (30.9%) and headache (30.9%) are the most common CVS symptoms experienced by respondents. This agrees with Bali et al (2007) who reported eyestrain (97.8%) and headache (82.1%) as chief presenting symptoms of CVS. Similarly, the findings in this study concur with the findings by Chiemeke et al (2007) who reported eyestrain (96.1%) as being the most common visual symptom experienced by computer users. They also reported blurred distance vision (83.6%), headache (81.6%), double vision (72.9%), redness of eyes (66%) and watery eyes (48.6%) as other common visual symptoms associated with computer use.

In terms of severity of symptoms, the current study records lower percentages than studies by Chiemeke et al (2007) and Bali et al (2007). The possible explanations include that because the respondents in this study are civil servants and due to the recent economic crises plaguing the country which has resulted in loss of jobs in the Nigerian civil service respondents may not have wanted to disclose their true visual status. Some respondents (though assured of anonymity and confidentiality by the researcher) may have the wrong perception that the results of this study would not work in their favour. Some methodological differences and settings between the studies may also have contributed to the differences in the values on the severity of symptoms.

Respondents that spend 6-8 hours average daily on the computer experience the highest CVS symptoms (49.3%), followed by respondents that spend more than 8 hours daily (26.1%) and respondents that spend 3-5 hours daily (23.9%). Respondents that spend 1-2 hours daily experience the least symptoms of CVS (0.7%). There is a likelihood of respondents that spend more than 8 hours daily on the computer taking more frequent breaks than those that spend 6-8 hours daily. This may partly explain why those that spend 6-8 hours daily experience more symptom than those that spend more than 8 hours on the computer daily. This finding is similar to Ihemedu & Omolase (2010, p.51) who reported that more symptoms were noticed amongst the computer users in the university and hospital compared to the bankers. They reasoned that it may be due to fear of subjects not exposing their possible ocular deficiencies or an adaptation of the subjects to the frequent computer use.

However, these findings do not correlate with the findings by Chiemeke et al (2007) who reported that visual symptoms associated with computer use were more experienced by respondents that spend more than 8 hours daily with computer. They further reported that visual symptoms begin to occur after 1 hour of computer work and increases with an increase in the number of hours spent on computer uninterrupted. Future studies need to be conducted in this area to corroborate these findings.

This study further revealed that the longer the duration in years of computer use, the more severe the CVS symptoms. Respondents that have been using computer for less than 1 year experienced the least symptoms (1.5%), 1-2 years (7.3%), 3-5 years (27%), while respondents that have been using computer for 6-8 years (32.1%) and more than 8 years (32.1%) experience the highest symptoms of CVS. Experimental and epidemiological lines of evidence have indicated that near work performed in the long term can alter the tonic accommodative status of the eyes which can influence the development of refractive errors (Borish 1998, p.40). This may be the reason why respondents who have been using computer for more than 6 years experienced more symptoms than others.

5.3 Conclusion

CVS has been classified as the number one occupational hazard of the 21st century (Torrey 2003). This statement cannot be overemphasised when one considers the upsurge in information technology, the proliferation of computer systems, and the overwhelming visual symptoms experienced by computer users as observed in this study. More so since the year 2000, 75% of daily activities of all jobs involve the use of the computer (Ihemedu & Omolase 2010, p.49). CVS significantly harms workplace productivity and reduces the quality of life by placing unusual strain on the human physical well-being.

The current study has explored the level of knowledge of CVS and the common visual symptoms experienced by computer users in the SEC workplace in Abuja, Nigeria. As reported in other similar studies, headache and eyestrain are the most frequent symptoms reported by respondents in this study. Duration in years of computer use and number of hours spent on computer are factors that influence the occurrence and severity of CVS symptoms. CVS knowledge level of 27% in this study was considered inadequate. Despite the shortcomings of this research, the results would serve as a knowledge base on which to build strategies for improving CVS knowledge. The results would be useful for policy makers, programme planners and eye care practitioners.

5.4 Recommendations

The findings of this study provide useful information on the knowledge level of CVS and visual symptoms experienced by computer users. It is important to note that a survey of this nature can be very educative by prompting respondents to obtain more information about the survey topic (Onunkwor 2011).

The current management of CVS in Nigeria and the recommendations made by other studies conducted in this area lay little or no emphasis on education of computer users. Given the low level of knowledge of CVS (27%) by the respondents in this study and the overwhelming symptoms experienced by 74% of the respondents, adequate education about CVS and its prevention amongst the people at risk is highly recommended.

This study reveals the internet as a major source of information for CVS by respondents. However, internet may not be easily accessible to most population groups in Nigeria. Therefore, Health Educators are encouraged to focus on dissemination of information through other means which are easily accessible to a wider population. This should involve seminar presentations at public offices and communication through the print and other electronic media.
oSpecial attention should be given to the young population. This includes children and students in schools, colleges and universities. As reported by Ihemedu & Omolase (2010, pp. 49, 50) children can experience many of the same symptoms related to computer use as adults and some unique aspects of how children use computers may even make them more susceptible than adults to the development of CVS. Training institutions are encouraged to develop learning materials and mainstream the training on CVS in their curricula.

• Eye care practitioners should endeavour to probe patients that attend the clinic about the history of computer use and spend time to discuss with their patients about CVS during consultations. Anshel (2006) suggests the issuing of questionnaires to acquire more information from patients about computer use. Izquierdo (2010) further suggests ergonomic visits to the patients office and emphasises that environmental factors such as computer set up, sitting, wrist position, monitor type, desktop colour, window proximity, ceiling and desk illumination sources should be evaluated.

Other recommendations especially for companies and institutions with large number of computer users should include:

Establishment of ergonomic guidelines to reduce visual complaints from computer usage (Chiemeke et al 2007). As practised in the United Kingdom, the Nigerian government should also establish a legislation to protect computer operators from ocular hazards inherent in computer use by setting out legal requirements of employees for their computer operators. The requirements should include that:

  • All computers fit a minimum specification for health use.
  • Work stations should be assessed for risk. All windows must be covered with blinds and monitors should not be exposed to direct light source to reduce glare on the screen.
  • Institutions should purchase ergonomic (adjustable) chairs for computer users in order to ensure that shoulders are not raised high and feet are firmly rested on the floor (Mvungi et al 2009).
  • Computer rooms should be well lit to avoid eyestrain (Chiemeke et al 2007).
  • All computer users should take regular breaks from computer work and be subjected to regular eye tests and special glasses provided if required.
  • Training on computer safety should be provided and relevant information relating to health and safety should be given to all computer users.

Finally, further research of this nature about CVS should be conducted in computer-using institutions in other parts of Nigeria.

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