|Year : 1968 | Volume
| Issue : 4 | Page : 217-220
Eye safety and eye health in transport operation
Southern Roadways P. Ltd" Madurai, India
|Date of Web Publication||24-Dec-2007|
Southern Roadways P. Ltd" Madurai
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Shrinivasan K. Eye safety and eye health in transport operation. Indian J Ophthalmol 1968;16:217-20
The protective mechanisms afforded by nature to our eyes are too well known but with the incredible speed at which we travel, faster and faster every day, even these mechanisms prove inadequate and we have to resort to artificial aids and devices to protect our eyes from accidental injury.
The hazards peculiar to transport operations, against which our eyes need to be guarded are:
- Flying particles, chips and pieces thrown off from machines or in an industrial process.
- Flying insects while travelling on an open road.
- Light of extra-ordinary brightness or intensity.
- Harmful rays from sources of light and heat.
- Irritating fumes generated in a chemical process.
- Corrosive or irritating liquids.
Adequate protection against most of these hazards is provided by the use of different types of goggles and face shields, designed for each hazard.
It is the foolish or careless disregard for such protection, sometimes through ignorance, that is the cause of these preventable accidents. Sometimes the cause is more a whim or obstinacy not to use goggles used by others, in which case it would be preferable to provide goggles for individual use. The employer's liability does not cease with providing of goggles, but their use must be enforced and constantly supervised.
Whenever possible, adequate protective shields or hoods should be designed and provided at the source of work which may obviate the various prejudices against the use of goggles, but such protection is not always available for all forms of work. For example, we have mounted transparent perspex shields of adequate thickness mounted on grinders for the protection of the eyes of the operator, whereas for portable grinders, goggles worn by the operator can offer the only source of protection to his eyes.
In transport operation, there are different classes of employees, who have to be safeguarded against different kinds of hazards. Maintenance and repair staff working underneath vehicles have to protect their eyes from falling mud or dust particles, while at work. Others in the repair shops need protection against flying chips and pieces thrown about by various processes. Even the simple process of washing a vehicle with a pressurized jet of water creates flying particles of mud and water.
Gas or electric welding needs protective filters for the workmen against radiations from the arc, which includes ultra-violet and infrared rays. Safety glasses provide protection against the intense light of the arc, against flying slag particles and irritating fumes for the welder and his mates.
Workers mixing acid for batteries, may get acid on their eyes unless they also wear protective goggles.
At monthly staff meetings, safety measures are explained and the importance of each individual cultivating safe working habits is stressed. As a result of these, we have a clean record free from eve-accidents and we have not lost a single man-hour over the past five years on account of any eye-injury or accident in our shops.
For drivers, eye-safety and eye-health are of particular importance. To drive a vehicle safely, he depends mainly on his sense of vision, every moment lie is behind the wheel. Through his eyes he receives an ever changing panorama, providing new information, which he has instantly to act upon.
Slight differences in road surface, road camber, tyre pressure, side wind or play in steering, are likely to change the path of a momentarily unguided vehicle. When the driver's eyes are diverted from the road ahead, for even a second, the car tends to wander. While driving at a sped of 30 miles per hour, the vehicle covers 44 feet every second and the consequencies of inattention to the road for even a fraction of a second can well he imagined.
It has been estimated that, while driving a vehicle in traffic of average density, a driver is required to take 10 decisions a mile, as he is driving. No other occupation makes such demands on decision making. Any visual deficiency causing delay in perceiving or interpreting traffic situations and in reacting to them correctly and quickly, constitutes a danger to the driver, his vehicle and its occupants, as well as to other road users.
In the course of his work, a driver is subjected to changing conditions of light and movement, which cause eye-fatigue. The constant wind that blows on his face tends to dry up his eyes and directs flying dust particles and insects on them.
All these factors go to show the importance of protecting the eyes of the driver and maintaining them in a good state of health.
The requirements in visual abilities of a driver are :
- Visual acuity
- Colour perception
- Depth perception
- Field of vision
- Night vision
- Glare vision and
- Glare recovery
Visual acuity is a measurement of seeing skill. Deficiency in visual acuity is corrected by wearing correct glasses. There should be no objection to a driver wearing glasses of reasonable power, say between +4 to -4D. Higher degrees of error should be certified by a specialist for safe-driving.
Colour perception: The driver should be able to distinguish green, amber and red colours used in traffic signals. If he is colour-blind lie has to learn to be cautious while passing through intersections controlled by traffic signal lights, and has to be taught to interpret the signal lights by their normal positions. But for night driving, especially of heavy vehicles, colour blindness should be a bar to driving.
Depth perception is judgment of distance, space and relative position of objects. Deficiency in depth perception is measured by the ability of the driver to line up two similar objects from a distance. A person may see near objects farther or far objects nearer. The former is a more serious defect as it will make the person feel that he is at a safe distance, while actually lie is not. If the driver is aware of his deficiency, he can compensate for it by allowing extra safe distance. However for fast driving and driving of heavy vehicles lack of depth perception should be a bar.
Field of vision is the extent of side vision, when eyes are aimed straight ahead. In no case a field of less than l0° on either side should be considered safe for driving.
Night vision. Any deficiency in night vision makes night vision driving hazardous and the driver has to reduce his speed to compensate for it. Some drivers over-drive their headlights. They drive at a speed at which it is not physically possible to stop in the distance illuminated by the beam of their headlamps, so they do not see the danger in time, to stop safely.
A decrease in the ability to see satisfactorily at night is quite noticeable among elderly people, in glaucomatous subjects and people with vitamin A deficiency.
Glare vision is the ability to recognise objects under low levels of illumination while the eves are subjected to glare. Eyes adjust more slowly to darkness than to light. Exposure to glaring head-lights makes subsequent adaptation to dim light considerably slow.
The time taken to recover from glare and recognise objects in reduced illumination is the glare recovery period, during which the driver cannot see properly. If the driver takes too long to recover from glare blindness, night driving becomes hazardous specially when driving on busy roads, curved roads or on hills, when bright headlights of on-coming vehicles appear suddenly and dazzle the eyes.
Slight deficiency in glare recovery can be compensated by reducing speed and driving well to the left. keeping the eyes away from direct glare, concentrating on the left side edge of the road, and allowing more safe distance while following other vehicles at night. If the deficiency is severe, a check for possible vitamin deficiency becomes necessary.
Tired eyes tend to make a driver feel drowsy. Dozing at the wheel causes many road accidents. Ability to judge distance and field of vision are greatly diminished when the eyes are fatigued.
Our lorries are not plied on service between the hours of midnight and 3 a.m. the period when, by nature, a man feels most sleepy. This restriction also limits the number of hours of night-driving required of a driver, and helps in reducing eye fatigue.
We have equipment to carry out tests: of the visual abilities of our drivers. A related test measures how quickly the driver applies brakes, under simulated road traffic conditions thus indicating the safe distance which the driver should allow in front of his vehicle at different speeds. As a result of these tests carried out on hundreds of drivers, 4% were found deficient in visual acuity and were sent to eye-specialists for getting corrective glasses prescribed. 25% of the drivers tested were deficient in depth perception, 25% in glare recovery, 13% in night vision and about 2% in colour perception. Only 55% of drivers were found satisfactory in all tests. By carrying out such tests, finding out the deficiencies and explaining their significance to the drivers for safe driving, they are made more cautious.
Eyes of drivers who drive , for long periods during day time are exposed to very bright sunlight. Eyes not protected in brilliant sun light require a very long period for the sensitive retina to become suitably adapted to darkness. If imperfect windshield glasses, which are not of uniform thickness throughout their areas are used, vision is distorted and due to the constant movement, eye strain is increased. In addition to this, the high degree of concentration on the road required for driving a vehicle, imposes a severe strain on the eyes. Cataract is found common in many drivers.
Use of glare glasses to lessen glare in the clay time aids night vision. Glasses also prevent direct entry of flying dust particles or insects into the eyes.
Our drivers are subjected to annual physical checks. Spectacles are supplied at Company's cost to needy drivers. Glare glass attachments or goggles are supplied free to all drivers. These measures promote their eye health and make them safe drivers.
There is need to develop and produce light-weight spectables and sun glass attachments, that can be worn for long periods without any discomfort. Use of ordinary shell frame spectacles or goggles which have covers for the sides of the eyes impair the field of vision. Rimless or thin rimmed curved glasses, which cover the sides of the eyes also, would be ideal for drivers and motorists, who drive for a number of hours.
For promoting eye health among the masses, simple eye exercises should be developed and published.
Visual deficiency is one of our most prevalent health defects. It is more serious among the aged, but failure to recognise and correct defects early in childhood, can adverserly affect the course of life. Vision care specialists are adding immeasurably to the happiness, welfare and greater usefulness of millions of persons they serve.
Eye safety, in the scientific sense, should be taught in the same manner as reading, writing and arithmetic, so that every individual will be made aware of the possible hazards. For ultimately, it is the individual who has to understand the dangers and take acre of his own eyes.
| Summary|| |
In transport operation, two types of jobs are considered,-driving and servicing. In servicing operations, the worker is subjected to the same kind of hazards as any machine-man with the added hazard of using a pressurized jet of water.
Acuity of vision, colour-vision, field of vision, night vision, glare vision and glare recovery are considered in their correct perspective of safety in driving.
Equipment to carry out tests of visual abilities of drivers is described and recommended and results of such tests carried out routinely for drivers before employment are: discussed.