Health Impact of Exposure to Computer Screens
This article addresses the health risks arising from exposure to computer screens, such as visual, physical and mental fatigue, and presents effective prevention and adaptation strategies in line with the Portuguese legal framework.
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Working with display screen equipment (EVD) entails exposure to occupational risks that can cause pathologies that have been widely studied in their users. The employer, with the support of its occupational safety and health service, has a duty to analyse and adapt workstations with risks that may affect the health of the workers in their service. The use of IT equipment is now transversal to all productive activities, with the tertiary sector being the one where the highest number of IT applications is found and, consequently, a greater exposure on the part of office and administrative workers.
Risk Factors
The risk factors associated with exposure to EVD can be summarised and grouped into:
- Related to the equipment: screen, keyboard, documents, desk, chair, cables, software.
- Related to the environment: space, lighting, reflections and glare, heat, emissions, humidity, noise.
- Related to work organisation: training of workers, daily work development, protection of workers' eyes and eyesight, posture at the workstation.
Most Frequent Effects
The most common effects can be grouped into:
Visual Fatigue
This is a functional and reversible alteration, caused by the excessive demand on pupillary reflexes and accommodation-convergence, which are necessary to focus the image on the retina. It affects between 10% and 40% of workers exposed to EVD daily.
The symptoms of visual fatigue can be grouped into three levels:
- Ocular discomfort: sensation of heaviness in the eyes, eye strain, heavy eyelids, itching and burning, need to rub the eyes, drowsiness, watering eyes, dry eyes, increased blinking, conjunctival redness.
- Visual disturbances: blurred characters on the screen, difficulty focusing on objects, blurred or double images, photophobia, accommodation-convergence problems due to the continuous need to adapt focus.
- Extraocular disturbances: headaches, vertigo or dizziness (especially in cases of poorly corrected visual deficits), anxiety, photosensitive epilepsy, unconscious adoption of a posture to avoid reflections, discomfort in the neck and spine due to excessive distance between the eyes and the text to be read.
Physical Fatigue
This involves a reduction in the individual's physical capacity due to muscle tension, or excessive tension of the body as a whole, or an excessive effort of the psychomotor system.
The main symptoms include:
- Pain in the spine (neck, nape, dorsal or lumbar spine), usually at the end of the working day.
- Other symptoms, such as contractures, tingling, tiredness, tennis elbow syndrome, carpal tunnel syndrome, de Quervain's tendinitis.
The cause is generally associated with maintaining static postures in front of the screen, without forgetting that these poor postural habits can be caused by uncorrected visual anomalies.
Mental Fatigue
Caused by excessive intellectual effort, it can manifest itself through:
- Neurovegetative and/or psychosomatic disorders: headaches, palpitations, tiredness, dizziness, tremors, sweating, diarrhoea, constipation, nervousness.
- Psychic disorders: anxiety, irritability, depressive states, difficulty concentrating.
- Sleep disorders: nightmares, insomnia, restless sleep.
Skin Alterations
Cases of skin irritation or allergic reactions have been described, predominantly on the face and neck, and sometimes on the hands, with a component of personal predisposition and associated with a dry environment or static electricity generated by the screen. Another phenomenon detected in recent years was Semicircular Lipoatrophy, attributed to the environmental and ergonomic conditions of workstations, generally in offices.
Radiation Emitted by EVD and Pregnancy
Studies carried out have not found any scientific evidence of a link between spontaneous abortions in women working with EVD and the radiation emitted. No evidence of links between adverse pregnancy outcomes and the use of screens was found.
Prevention of Health Impacts from EVD
The prevention of risks is fundamental to avoid the appearance of the potential damages described and involves, at least, and in summary:
- Adequate ergonomic design of the workstation.
- Risk detection and assessment.
- Adequate environmental conditions.
- Specific training for workers.
- Maintaining good physical fitness.
- Taking care of posture and respecting work breaks.
- Using appropriate optical correction for visual acuity in case of deficiencies.
- Correct protocolled preventive health surveillance, through a specific occupational medical examination for the risks of working with EVD, to detect health damage early and identify particularly sensitive workers. This individual health surveillance must be offered by the employer to workers exposed to EVD:
- Before starting work with a display screen.
- Subsequently, with a frequency adjusted to the level of risk, at the discretion of the responsible doctor.
- When disturbances arise that can be attributed to work with display screens.
In Portugal, Article 131 of the Portuguese Labour Code establishes the importance of continuous training, including occupational safety and health. Although it does not specifically detail EVD, Portuguese legislation, through decrees such as Decreto-Lei n.º 349/93, of 30 September, transposing a community directive, defines the minimum safety and health requirements for work with equipment equipped with EVD, thus reinforcing the need for employers to guarantee training and adequate conditions to prevent the associated risks. Compliance with these standards is essential to protect workers' health and ensure a safe and productive working environment.
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Working with display screen equipment (EVD) entails exposure to occupational risks that can cause pathologies that have been widely studied in their users. The employer, with the support of its occupational safety and health service, has a duty to analyse and adapt workstations with risks that may affect the health of the workers in their service. The use of IT equipment is now transversal to all productive activities, with the tertiary sector being the one where the highest number of IT applications is found and, consequently, a greater exposure on the part of office and administrative workers.
Risk Factors
The risk factors associated with exposure to EVD can be summarised and grouped into:
- Related to the equipment: screen, keyboard, documents, desk, chair, cables, software.
- Related to the environment: space, lighting, reflections and glare, heat, emissions, humidity, noise.
- Related to work organisation: training of workers, daily work development, protection of workers' eyes and eyesight, posture at the workstation.
Most Frequent Effects
The most common effects can be grouped into:
Visual Fatigue
This is a functional and reversible alteration, caused by the excessive demand on pupillary reflexes and accommodation-convergence, which are necessary to focus the image on the retina. It affects between 10% and 40% of workers exposed to EVD daily.
The symptoms of visual fatigue can be grouped into three levels:
- Ocular discomfort: sensation of heaviness in the eyes, eye strain, heavy eyelids, itching and burning, need to rub the eyes, drowsiness, watering eyes, dry eyes, increased blinking, conjunctival redness.
- Visual disturbances: blurred characters on the screen, difficulty focusing on objects, blurred or double images, photophobia, accommodation-convergence problems due to the continuous need to adapt focus.
- Extraocular disturbances: headaches, vertigo or dizziness (especially in cases of poorly corrected visual deficits), anxiety, photosensitive epilepsy, unconscious adoption of a posture to avoid reflections, discomfort in the neck and spine due to excessive distance between the eyes and the text to be read.
Physical Fatigue
This involves a reduction in the individual's physical capacity due to muscle tension, or excessive tension of the body as a whole, or an excessive effort of the psychomotor system.
The main symptoms include:
- Pain in the spine (neck, nape, dorsal or lumbar spine), usually at the end of the working day.
- Other symptoms, such as contractures, tingling, tiredness, tennis elbow syndrome, carpal tunnel syndrome, de Quervain's tendinitis.
The cause is generally associated with maintaining static postures in front of the screen, without forgetting that these poor postural habits can be caused by uncorrected visual anomalies.
Mental Fatigue
Caused by excessive intellectual effort, it can manifest itself through:
- Neurovegetative and/or psychosomatic disorders: headaches, palpitations, tiredness, dizziness, tremors, sweating, diarrhoea, constipation, nervousness.
- Psychic disorders: anxiety, irritability, depressive states, difficulty concentrating.
- Sleep disorders: nightmares, insomnia, restless sleep.
Skin Alterations
Cases of skin irritation or allergic reactions have been described, predominantly on the face and neck, and sometimes on the hands, with a component of personal predisposition and associated with a dry environment or static electricity generated by the screen. Another phenomenon detected in recent years was Lipoatrophy Semicircular, attributed to the environmental and ergonomic conditions of workstations, generally in offices.
Radiation Emitted by EVD and Pregnancy
Studies carried out have not found any scientific evidence of a link between spontaneous abortions in women working with EVD and the radiation emitted. No evidence of links between adverse pregnancy outcomes and the use of screens was found.
Prevention of Health Impacts from EVD
The prevention of risks is fundamental to avoid the appearance of the potential damages described and involves, at least, and in summary:
- Adequate ergonomic design of the workstation.
- Risk detection and assessment.
- Adequate environmental conditions.
- Specific training for workers.
- Maintaining good physical fitness.
- Taking care of posture and respecting work breaks.
- Using appropriate optical correction for visual acuity in case of deficiencies.
- Correct protocolled preventive health surveillance, through a specific occupational medical examination for the risks of working with EVD, to detect health damage early and identify particularly sensitive workers. This individual health surveillance must be offered by the employer to workers exposed to EVD:
- Before starting work with a display screen.
- Subsequently, with a frequency adjusted to the level of risk, at the discretion of the responsible doctor.
- When disturbances arise that can be attributed to work with display screens.
In Portugal, Article 131 of the Portuguese Labour Code establishes the importance of continuous training, including occupational safety and health. Although it does not specifically detail EVD, Portuguese legislation, through decrees such as Decreto-Lei n.º 349/93, of 30 September, transposing a community directive, defines the minimum safety and health requirements for work with equipment equipped with EVD, thus reinforcing the need for employers to guarantee training and adequate conditions to prevent the associated risks. Compliance with these standards is essential to protect workers' health and ensure a safe and productive working environment.