The eye is particularly vulnerable to physical and chemical damage, and such damage is often permanent, leading to irreversible effects on eyesight. In the first of two reports on occupational health risks to the eyes, Gordon Tranter explains how to understand the risk to eyes from contact with chemicals and infectious diseases.
What are the occupational risks to eyes?
Occupational risks to the eyes include contact with chemicals, infectious diseases, damage from exposure to high intensity ionising and non-ionising radiation, and the risk of damage from visually demanding work.
Eyes can be damaged by solid, liquid, powder, gaseous or aerosol chemicals and this damage can be permanent, leading to irreversible effects on eyesight. The severity of a burn depends on the substance that caused it, how long the substance had contact with the eye and how the injury is treated.
Substances that cause eye damage/eye irritation are classified by the European Regulation No. 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP) into two categories with Hazard Statements.
H318: Causes serious eye damage. Serious eye damage is defined as the production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance to the anterior surface of the eye, which is not fully reversible within 21 days of application.
H319: Causes serious eye irritation. Eye irritation is defined as the production of changes in the eye following the application of test substance to the anterior surface of the eye, which are fully reversible within 21 days of application.
Damage from chemicals is usually limited to the front segment of the eye, including the cornea (the clear front surface of the eye), the conjunctiva (the layer covering the white part of the eye) and occasionally the internal structures of the eye, including the lens. Burns that penetrate deeper than the cornea are the most severe, often causing cataracts and glaucoma. Alkaline solutions may penetrate all layers of the eye.
In addition to irritation due to a substance’s chemical properties, eye irritation can result from the physical form of a substance, eg dust from construction work. Foreign bodies are usually just irritating, and easily rinsed out by tears or water. If not removed, foreign bodies can cause corneal abrasions.
The Control of Substances Hazardous to Health Regulations 2002 require:
a risk assessment to be carried out before work that is liable to expose any employees to any substance hazardous to health (SHH)
steps to be taken to prevent the exposure of employees to SHH or, where this is not reasonably practicable, adequately controlling the risks
that only where adequate control of exposure cannot be achieved by other means, should suitable personal protective equipment ((PPE) be provided in addition to the measures required.
Where there is the possibility of chemical splashes to the eye, all staff should wear eye protection. There is wide variation in the types of protective eyewear. The protection chosen for specific work situations depends on the circumstances of exposure, the extent of the hazard, other PPE being used and personal vision needs. Eye protection must be comfortable and allow for sufficient peripheral vision and must be adjustable to ensure a secure fit.
Chemical splashes can come from all sides; consequently, full eye enclosure should be selected. As a minimum, safety glasses with side protection should be worn. Safety glasses do not provide the same level of splash or droplet protection as goggles. If employees could be exposed to chemicals that may affect other parts of their face, a full face visor may be necessary. Not only do full face visors protect a large area, but with their ventilation they generally remain mist-free. Goggles with appropriate ventilation systems should be selected for protection against vapours and gases.
Employees who wear prescription spectacles may need to wear eye protection. Many safety goggles or non-prescription safety glasses fit comfortably over normal eyewear and can provide satisfactory protection without impairing the fit of the prescription spectacles. Prescription safety glasses with side protection are available, but do not protect against splashes or droplets as effectively as goggles.
Where the eye protection is used with other PPE, care must be taken to ensure the eye protection fits properly. As an example, eye protection and respiratory protection that are incompatible increase the risk of respiratory exposure.
Protection of others
If a risk assessment indicates that an employee requires eye protection when carrying out an operation, but other people working in or visiting the area are not at risk, only employees using the chemical need to be provided with eye protection. However, if other people are likely to be at risk, the area should be designated and signed as an “Eye protection area”, in which all personnel must wear eye protection.
Where chemicals are used, eyewash facilities must be readily available, either in the form of an eye wash fountain or plenty of eyewash bottles (sterile water or saline).
Health and Safety Executive guidance INDG347 Basic Advice on First Aid at Work recommends that “if chemicals are involved, flush the eye with water or sterile fluid for at least 10 minutes, while gently holding the eyelids open. Ask the casualty to hold a pad over the injured eye and send them to hospital.”
Any chemical burn to the eye must be reported as a major injury under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013.
Workers such as health care workers, laboratory staff and animal handlers may be at risk of acquiring infectious diseases via eye exposure. Infectious diseases can be transmitted through the mucous membranes of the eye as a result of direct exposure (eg blood splashes, respiratory droplets generated during coughing) or from touching the eyes with contaminated fingers or other objects. Infections transmitted in these ways include viruses and bacteria that can cause conjunctivitis (eg adenovirus, herpes simplex, Staphylococcus aureus) and viruses that can cause systemic infections, particularly bloodborne viruses (eg hepatitis B and C viruses, HIV), herpes viruses and rhinoviruses.
Eye protection, such as goggles, face shields or full face respirators, must be used to provide a barrier to infectious materials entering the eye. Safety glasses do not provide the same level of splash or droplet protection as goggles and generally should not be used for infection control purposes. The PPE required during hospital care of Covid-19 patients includes goggles or face shield.
In some situations, particularly for health care workers, the eye protection may become contaminated. This may necessitate removal of the contaminated eye protection by handling only the portion of this equipment that secures the device to the head and wearing protective gloves. Reusable eye protection should subsequently be cleaned and disinfected.
Splash exposures to the eye should be flushed with water or with fluids designed for irrigating the eye. Any splashes of body fluids into the eye should be reported to an occupational health specialist, even if it is thought that there is not an infection risk, because the body fluid may be unknowingly infected.
The second part of this feature looks at the protection from damage caused by exposure to high intensity ionising and non-ionising radiation and the risk of damage from visually demanding work.