Vision Screening

TC-Vision-ScreeningFew would deny that clear vision is a critical aspect of many organisations. Whether your job involves driving, visual inspection, quality control, or making life or death decisions, your vision is one of the most important elements of safe and effective job performance.

In our continued efforts to complement and enhance our customers’ occupational health and safety programs, Levitt-Safety | EHS Training & Consulting Services now offers vision screening as part of our suite of client services.  Vision screening testing provides employers the ability to make sure employees who operate motorized vehicles as part of their day to day work, or who are involved in quality control activities, can maintain the same standard of care in the work they perform.

How many departments in your organisation have requirements for visual inspections?  How many of the codes, regulations, and legislative mandates demand that visual inspections be performed on a regular, weekly, monthly, quarterly, or annual basis? Think of the requirements for slings and wire ropes, aircraft parts, hazardous waste containers, forklift operators, and every commercial vehicle and load—the list goes on and on.  Yet how many of those same codes have a single line that requires the inspectors (your employees!) to be able to see – and see correctly?

What Are the Key Components of a Safe Sight Program?

  • Visual acuity
  • Useful field of view
  • Colour correct sight
  • Depth perception
  • Contrast sensitivity, and
  • Light levels

Your job descriptions should have not only the specifications for the physical aspects of the job (stand for six hours, be able to lift up to 25 pounds, 10 times in a shift), but also the visual requirements.  Let’s examine each one individually in terms of how it might be involved in incidents we investigate:

A depisteo vision screener and laptop computerVisual Acuity

Acuity is how clearly a person can see an object. This is generally specified as “20/20 vision” for someone with good vision, and is usually measured by a Snellen chart. Your employee is required to maintain the pressure of the reaction system at 200 psi using an analog gage. If the pressure gets below 195, the material will not react properly, and you have a ruined batch. If the pressure gets above 220 psi, the reactor will explode. Sure, you can install an electronic system that can control the pressure, but how much will that cost in time and equipment?

Ensuring your employees can see correctly provides the necessary management of the process. An employee with poor visual acuity will need to stand back or move closer to the gauge to see it clearly. If they are back too far, they may not be able to see the gauge reading correctly. If they have to move in too close, they could be burned by coming into contact with the reactor.

Field of View

The field of view is the angular direction that you can see. Human beings have almost 180 degrees of vision. Try this: stand up and look straight ahead. Extend your arms straight out to your sides and wiggle your fingers. Do not turn your head or your eyes; keep them straight ahead. Slowly move your arms in together, and stop as soon as you see your fingers. Most people with a normal field of view will be able to see the fingers at an equal angle. Others may not be able to because of an eye disease or a visual problem. While you are still standing, raise one arm above your head and lower the other arm straight down. Again, wiggle your fingers as you slowly move your arms together, and stop when you can see your fingers. If you do not see your fingers wiggling at almost 180 degrees, it may mean you need to be examined by an eye doctor.

Colour Vision

We’ve all had these tests, trying to determine the number that is hiding in a circle of dots. Is it a 3 or 27? A percentage of the population is colour blind. Two of the more common types of colour blindness are red-green and blue-red blindness. Image if you had never been tested, never needed to know trees were green and Christmas ornaments were red. What would happen when you started to drive a motor vehicle and that signal ahead lit up at the top? Do you stop or do you go? If the pump is running, the light is green. If the pump stops, what colour is the light? Can your employees tell the difference?

Depth Perception

Why do people step off the sidewalk when they didn’t mean to? Why do some people have problems walking up and down stairs? They have impaired depth perception. What do baseball players, waitresses, and dentists all have in common? They all need good depth perception to be able to do their jobs correctly.

Contrast Sensitivity and Light Levels

Contrast is the difference in the highlights and background of an image. When you look at trees just before sunrise, they all seem to be grey and very indistinct. Not many of the details are visible. Then, as the sun comes up, you see the colours start to develop into what they should be; you see the details in the branches and the leaves, and you see the sky go from black to gray to blue. What you are seeing is an increase in contrast as the light levels increase.

Another way to try this is with a light that is on a dimmer. At night, or with all other lights out, notice the room. Look at the details in a fabric drapery and the colours in the rug. While you are observing these details, slowly lower the light level. What happens? Where did the colours go? Where did the details disappear?

Will your forklift driver be able to determine what information is on the label of the carton on the third level when he’s working the third shift and you have less than optimal illumination?

Implementing Your Vision Program

Implement your vision program by putting the six components of a safe sight program into place. Develop the vision criteria for all of the tasks at your facility and include them in the job specifications for the positions, and test your employees to ensure they meet the requirements. Have them get corrective lens if they are required, and ensure they’re being used. If you need assistance developing your vision program, or with vision screening your employees, contact us today.