Vision Examinations
Thousands of South African employees experience occupational eye injuries, often resulting in permanent damage and even blindness in some cases. The impact of daily job processes can have a negative effect on eye health. Eye hazards can include many causes, some of which may be the emissions of unacceptable levels of toxins, particulate matters, foreign objects get in the eye and eye ergonomics. These causes and many more can cause significant eye irritations and injuries, which can lead to permanent ocular damage. Nine out of ten eye injuries could be avoided if visual safety was practiced in the work environment and the appropriate eye protection provided and used. However, visual safety in a work environment extends beyond the prevention of eye injuries. Vision assessments should be conducted to ensure that workers possess the minimum level of visual functioning needed to accomplish visual tasks and that ocular hazards are identified.
A comprehensive eye examination to detect eye diseases, binocular vision disorders, visual damage, deterioration and refractive problems can be done so that corrections may be incorporated into workplace safety plans, regulations, policies and programmes, especially those with eye hazards. Annual vision screenings allow the employer to identify changes in the visual function and ocular health of a worker that could potentially affect safety or eye health in the future. In occupational health medicals there are two commonly used visual examinations.
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Visual Acuity Snellen Chart Examination.
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Visual Screening Examination.
Visual Acuity Snellen Chart Examination:
A measure of a person’s acuteness of vision, and the most commonly used measurement of visual function and status. Patients are examined at a distance to assess what can be seen by using a standard Snellen Acuity Chart which has a series of letters, numbers, or a combination of letters and numbers, with the largest at the top. The person being tested reads down the chart. The result is taken as the smallest row that is accurately read. A system using a 20/20 visual acuity standard can be used as a guide for the appropriate placement of workers.
Visual Screening Examination:
The Occupational Health and Safety Act14 and the Mine Health and Safety Act15 and their regulations give direction on the provision of a safe working environment to mitigate hazards and ensure workers’ health and safety. Eye health and safety has recently been recognised as an essential component of occupational health and safety regulations. For example, the Driven Machinery Regulations and the National Code of Practice for the Evaluation of Training Providers for Lifting Machine Operators16 provides guidance for drivers of heavy duty, lifting and moving machinery, such as forklifts. It indicates that any person undergoing training to control such machinery, such as a forklift, must be in possession of a valid Professional Driver’s Permit (PDP) issued by a doctor who confirms that the trainee has adequate day and night vision and depth perception. The certificate or permit is used to declare the person suitable for the operation of the moving machinery. Thousands of heavy machinery operators sustain injuries to themselves annually, mostly resulting from the failure of the safety programme in place or lack of optimal visual function. That is why testing employee’s vision fields are so important.
A Visual Screening Exam can include the following tests:
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Visual Acuity – Right eye, near and far
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Visual Acuity – Left eye, near and far
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Visual Acuity – Both eyes, near and far
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Phoria – Vertical and lateral, eye coordination
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Fusion – Eye’s ability to merge right and left eye
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Stereopsis – Depth perception
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Color perception – Severe and mild deficiency
