Pathophysiologic Mechanisms of Computer Vision Syndrome and its Prevention: Review

Abstract

Nowadays the computer has changed and eased the lives of many people in the workplace. Office work, conducting research, preparation of notes and other computer related works have always involved a range of activities, such as typing, filing, reading, and writing. With the evolution of the computer, all these tasks can now be completed using one device. Desktop, tablets, smart phones and personal computers are some of the visual display units, used for different purposes in institutions, at workplaces and other recreational areas. But apart from their advantage, usage of visual display units have risk of developing computer vision syndrome (CVS) which is one of the emerging public eye health problems in the world. CVS is one of the most important occupational hazard of the 21 st century which affects 70 percent of all computer users [1].The American Optometric Association defines CVS or digital eye strain as a ''group of eye and vision-related problems that result from prolonged computer, tablet, e-reader and cell phone use'' [2].Nearly more than half of the world's populations are using the internet as described by Internet world stats [3]. It is estimated that nearly 60 million people suffer from CVS globally, and that a million new cases occur each year [4]. The most encountered symptoms during computer usage are reduced blink rate, tired eye, headache, neck pain, blurring of vision eye strain [5-8]. It is also stated that the performance of the human vision system is reduced due to long period usage of computer and discomfort lightening conditions [9]. It is also known that blue light emitted from a computer screen can reduce the amount of melatonin [10]. Annoying reflections [11], head position and direction of gaze during performing on visual display units can lead to symptoms of CVS [5].CVS significantly impairs workplace productivity and reduces the quality of life by placing unusual strain on human physical well-being as well as reduce job satisfaction and lost work time [1,12,13]. It is also known that CVS can reduce work accuracy in specific tasks by as much as 40% [1]. Reading from a computer screen can reduce understanding ability compared to reading test on print paper [14], which in turn may affect schooling or work-

Computer vision syndrome: a rising problem during COVID-19 period amongst students and online workers

“…Extraocular related. 4 Personal factors include reduced eye movement, poor posture, and poor distance while working on a computer without a break in between. Environmental factors are associated with poor lighting and its imbalance with computers and the surrounding environment.…”

“…Extraocular risk factors include pain in the neck, back, and shoulder. 4 The prevalence of computer vision syndrome is increasing in the world as well as in Nepal. In an online questionnaire-based study among higher secondary school children in India who were attending online classes during the COVID-19 pandemic, the mean duration of digital screen exposure increased from 1.9 ± 1.1h (before COVID) to 3.9 ± 1.9 h (after COVID).…”

“…The CVS was seen in workers who spent >4.75 h/d on the computer. 10 4,11 Diagnosis of CVS includes detailed history taking and complete ocular examination. Following the patient's history, clinical examination including binocular vision test, refraction test, and tear film assessment should be done.…”

“…Following the patient's history, clinical examination including binocular vision test, refraction test, and tear film assessment should be done. 4 Optical correction of refractive error is the mainstay for treating CVS as it can decrease the stimulus to accommodation. Dietary supplement of Omega-3 fatty helps maintain tear stability.…”

“…In the case of dry eyes, artificial tear supplements like Carboxymethyl cellulose (CMC) and Hydroxypropyl methylcellulose (HPMC) can be used. 4,12 Preventive factors to avoid this condition should mainly focus on the working environment, i.e, ergonomic factors which affect the course of CVS. The proper sitting position in front of the computer display, proper lighting of the room, brightness and contrast of the screen, angle and distance of eye to the screen (mean distance of eye to the screen should be 60-80 cm for computer screen, 30 cm for cell phone), including height of computer screen at the level of the eye should be maintained to prevent from eye fatigue, dryness and eventually CVS.…”