Health surveillance means planned regular health assessments based on best practices and legislation for all workers exposed to risk in the workplace, this includes vision screening5. Part of medical surveillance is the correct maintenance and storage of medical records, informing workers about the state of their health (which includes visions) and assessing the proper fit, cleaning, and maintenance of any personal protective equipment. Employees are required to co-operate with a health surveillance programme that includes vision screening by presenting at health surveillance appointments and cooperating with healthcare providers in full to achieve the best (most accurate) results possible.
Vision screening is only one component of a (VPP) and is done to prevent loss of vision and eye injuries and not to monitor them. Vision screening is done as required by legislation discussed in Chapter 3 and once the results are available action and exclusion criteria and interventions are required. Unlike audiometry where there is a great deal of legislation and consensus regarding fitness to work, action and exclusion criteria and minimum standards of vision required across the board, vision screening / eye conditions and sight are still being debated, a great deal of differing opinions exist.
All employers are required to advise the occupational medical practitioners of the hazards and risks in the workplace therefore assisting the medical team to decide on the required medical surveillance required, the intervals of assessment and management of the effects of exposure. Often this is contained in a code of practice for fitness to work or in action and exclusion criteria
Action criteria relating to fitness for work or exposure to ocular hazards and increased risk is defined as the minimum visual acuity required before certain interventions must take place. Exclusion criteria for eyes and eyesight vary from one industry to another, from one job type to another and from country to country. Exclusion criteria disqualify workers from certain safety critical work, certain hazards, and visual risks.
Both action and exclusion criteria are legislated in mining operations, maritime and aviation industries, and transportation however it is not legislated in other industries where it remains the responsibility of the OMP in conjunction with the company to develop action and exclusion criteria to ensure a consistent approach to deal with abnormal results. These guidelines are often developed within certain types of industries in mind and international standards are used. For example:
Rail Safety Regulator – Human Factors management has a minimum fitness for duty guidelines. South African Maritime Safety Authority – has sea farers minimum fitness guidelines. South African Civil Aviation Authority – has minimum fitness guidelines for aviation.
In some instances, a “grandfather” clause may apply which allows existing workers to continue working with certain visual limitations but bars the employment of new workers with the same limitations from entering the workforce17,18,19.
In this chapter the most common action and exclusion criteria and minimum standards of fitness (relating to eyes and vision) will be outlined but technicians / OMP’s and OHNP’s need to ensure that the risks in the working environment where they are employed are defined and agreed to and meet best practice guidelines for that industry.
Table 10.1 Adapted from the Merchant Shipping Act19
Eyes / Vision
No person should be accepted for training or service at sea if an irremediable morbid condition of either eye, or the lids of either eye, is present and liable to the risk of aggravation or recurrence.
Binocular vision is normally necessary for all seafarers; however, monocular serving seafarers, and those who become monocular in service, who meet the required standard should be allowed to continue to serve at sea.
In all cases where visual aids (spectacles or contact lenses) are required for the efficient performance of duties, a spare pair must be carried when seafaring.
Where different visual aids are used for distant and near vision a spare pair of each must be carried.
Persons wishing to serve in the deck department or considering dual qualifications are strongly advised to have their eyes tested by an eyesight examiner before embarking on their career, in view of the particular importance for them of good eyesight.
In the case of seafarers serving, or intending to serve, in the deck department and required to undertake watchkeeping duties, colour vision is tested with Ishihara plates, using the introductory plate and all the transformation, and vanishing plates.
A person who fails this test may be referred to an eyesight examiner for further examination using the Holmes Wright Type B lantern test, in accordance with Annex 2.
In the case of seafarers serving, or intending to serve, in other departments, colour vision is tested using Ishihara plates (as for deck department).
Table 10.2 Adapted from ANNEX 2 (Regulation 20) Colour and Form Vision Tests19
These tests are applicable to seafarers required to undertake watchkeeping duties in the deck department
Type of Seafarer
1. New entrants and all first-time applicants for certification in terms of the seafarer certification regulations.
Form test - Without aids to vision
The candidate is to read correctly down to and including line 7 with the better eye, line 6 with the other and line 6 with both eyes.
Form test - With aids to vision
First test without the aids to vision, the candidate is to read correctly down to and including line 5 with the better eye, line 3 with the other eye and line 3 with both eyes.
Then with the aids to vision, the candidate is to read correctly down to and including line 7 with the better eye, line 6 with the other eye and line 6 with both eyes.
A candidate who mistakes red for green or vice versa, in the large or small apertures is taken to have failed the test.
A candidate who on more than six occasions in four full and one broken circuit of the small apertures, confuses red for white or white for green or vice versa, is taken to have failed the text.
A candidate is permitted to read the lights with or without aids to vision, but aids to vision that are designed to correct or adjust colour vision deficiencies may not be used.
2. Other applicants for certification in terms of the seafarer certification regulations, and all applicants for pilotage exemption.
(a) Candidate under 40 years of age—as for item 1.
(b) Candidate being 40 years of age or older— Without aids to vision
The candidate is to read correctly down to and including line 7 with the better eye, line 5 with the other eye and line 5 with both eyes.
With aids to vision - first test without aids to vision, the candidate is to read correctly down to an including line 3 with both and then either eye.
Then test with aids to vision, the candidate is to read down to an including line 7 with the better eye, line 5 with the other eye and line 5 with both eyes.
As for item 1, except that a candidate who has previously passed the lantern test may be taken to have passed this test if he or she reads correctly the "Ishihara" plates 1. 11, 15, 22 and 23.
Binocular vision is a requirement for new entrants.
Seafarers who become monocular in service are required to meet the standard for the better eye, specified in the table above (an example of the grandfather clause)
A candidate who requires darkness adaptation in the lantern test is permitted a period of 10 minutes in a darkened room for his or her eyes to adapt to the darkness.
A candidate who fails the form or lantern test may repeat the test at the discretion of the Authority.
Candidates will be notified in the appropriate form of the test results, or if their case has been referred for consideration.
A candidate who is ill on the day of the test or who is on medication at the time of the test stands a chance of failing the test. These candidates should be given an option of attempting the test at a later time when well.
Candidates are to declare to the eyesight examiner whether or not they will be using contact lenses during the tests. A candidate who fails to declare the use of contact lenses will be penalised by being prohibited from completing the test for a period of two years from the date he or she last completed the test, and the results of that test will be revoked in writing by the Authority.
candidate who uses aids to vision to pass the form test must show the eyesight examiner two pairs of such aids to vision
Table 10.3 has been developed by the rail safety regulator as a guideline for vision criteria in the rail industry. This table recommends the standards for visual acuity for certain job types.
Table 10.3 Eyes and Vision Criteria in the Rail Industry20
Table 10.4 has been developed by South African Society of Occupational Medicine (SASOM) and is available in the SASOM Guideline 26, Vision Testing17,18. This table recommends the standards for visual acuity for certain job types. This table is ideal when starting out in an industry and can be added to and adjusted to meet the visual requirements by task where the technician / OHNP / OMP works.
This is not a complete table of all known job titles and the minimum fitness criteria.
Use this list as the basis for your own list of criteria and job titles
Add to the table as you find jobs and criteria not listed and specific to your working environment.
Table 10.3: Recommended vision standards by type of occupation17,18
Long-standing monocular vision is acceptable for code 8 drivers. However, for employees with recent loss of vision in one eye, should be temporarily reassigned until they have successfully adapted to monocular vision (usually 3-6months).
Cat V1: Primary colours only.
Cat V2: Secondary & tertiary colours.
Cat V3: Contrasts & hues (Ishihara).
Cat V4: Other (e.g., Coloured wires (electricians), Holmes- Wright type B lantern (seafarers)
Cat P1: 70 degrees temporal, or where one eye is blind, a minimum total horizontal visual field of at least 115 degrees.
Cat P2: 70 degrees temporal. (A normal visual field refers to at least 50 degrees nasal and 70 degrees temporal vision).
**** Binocular vision
Binocular vision enables adequate peripheral vision and to a lesser extent depth perception. Depth perception can be acquired even in the absence of binocular vision, whereas peripheral vision cannot. However, a reduction of peripheral vision (i.e., monocular) may be acceptable when the vehicle being operated is slow-moving, and where the movement of people around it is minimal.
Colour vision and normal visual fields are required for passengers, dangerous and non-dangerous goods conveyances, and certain other occupations, such as electricians. A normal visual field refers to at least 50 degrees nasal and 70 degrees temporal vision.
Minimum Criteria of Fitness for Drivers in Terms of the National Road Traffic Act, No 93 of 1996
A person is disqualified from obtaining or holding a learner’s or driving licence in terms of the National Road Traffic Act, Act 93 of 1996 if15:
in the case of a learner’s or driving licence application for codes A1, A, B or EB a minimum Snellen rating for visual acuity, with or without refractive correction is not met. The minimum Snellen visual acuity should be 6/12 (20/40) for each eye, or where the visual acuity of one eye is less than 6/12 (20/40) or where one eye of the person concerned is blind, a minimum visual acuity for the other eye of 6/9 (20/30); and a minimum visual field of 70 degrees temporal, with or without refractive correction, in respect of each eye, or where the minimum visual field in respect of one eye is less than 70 degrees temporal, or where one eye is blind, a minimum total horizontal visual field of at least 115 degrees with or without refractive correction.
in the case of an application for a learner’s or driving licence relating to codes C1, C, EC1 or EC, a minimum Snellen visual acuity, with or without refractive correction is 6/9 (20/30) for each eye; and a minimum visual field of 70 degrees temporal in respect of each eye, with or without refractive correction.
A person who is disqualified may be referred to a registered optometrist or ophthalmologist to retest the vision and the result of such test must be reflected as the visual acuity of the person.
Professional driving permits are divided in the following categories and will need to meet the visual acuity standards listed above:
Category “G”, which authorises the driving of a motor vehicle as referred to in regulation 115(1)(a) and (b);
Category “P”, which authorises the driving of a motor vehicle referred to in regulation 115(1)(a), (b), (c), (d), (e) and (g); and
Category “D”, which authorises the driving of a motor vehicle referred to in regulation 115(1).
A registered medical practitioner or occupational health practitioner must examine the applicant to determine whether or not he or she is disqualified from driving a motor vehicle as contemplated in section 15(1)(f) of the Act and must certify the applicant as medically fit on form MC not more than 2 months prior to the date of the application.
Table 10.5 has been developed by the South African Society of Occupational Medicine (SASOM) and is available in the SASOM Guideline 6 Guideline of the Medical Requirements for Fitness to Driver18. This table recommends the standards for visual acuity for certain job types. The NRTA requires that a licence holder or applicant be considered as suffering a prescribed impairment if unable to meet the eyesight requirements.
SASOM Driver Categories:
Drivers of light motor vehicles and motorbikes. There is no PrDP requirement. The fitness criteria is the same for codes A1, A, B or EB.
These are drivers who require a PrDP. This is a higher risk category, but within this group there is a gradient of risk. The fitness criteria is the same for codes C1, C, EC1 or EC.
Category “D”: highest risk - authorises the driving of a motor vehicles carrying hazardous/dangerous goods.
Category “P”: second highest risk - authorises the carrying of passengers
Category “G”: third highest risk - authorises the driving of large motor vehicles conveying goods.
Special vehicle drivers in control of specialised vehicles, are vehicles which are used for specific purposes where skill, method of operation and place of operation require attention and additional training e.g., Forklift truck operators, crane drivers, etc. Note that, unless these vehicles are driven on public roads, the legislation that usually governs fitness to drive is not the National Road Traffic Act, but the Construction Regulations and the National code of practice for the evaluation of training providers for lifting machine operators, as per the Driven Machinery regulations of the Occupational Health and Safety Act and the Mines Health and Safety Act.
Special considerations for visual disorders for all drivers.
The visual acuity must be at least, according to the Snellen rating, a minimum visual acuity, with or without refractive correction, of 6/12 (20/40) for each eye, or where the visual acuity of one eye is less than 6/12 (20/40) or where one eye of the person concerned is blind, a minimum visual acuity for the other eye of 6/9 (20/30). If unable to meet this standard, the driver must not drive, and the licence must be refused or revoked. The law also requires all drivers to have a minimum field of vision, as set out in the NRTA.