Have you ever considered the importance of your eyes when it comes to road safety? In this piece, originally published by ArriveAlive, we consider the numerous "eye-opening" factors; visibility, glare, sun damage, and eye protection; all affecting road safety.
Our eyes and eyesight are perhaps the most important of our senses on the road. Seeing is a highly active function. Our eyes continually move and adjust, receiving a constant flow of visual impressions. Normally, all this activity happens routinely and without noticeable strain. It is important to identify those factors that might place stain on our eyes and reduce our ability to observe on the road.
Every day we are exposed to ultraviolet (UV) radiation from the sun. Most of the time we don't even realize it, as UV radiation is invisible to the eye. Over time UV radiation can cause severe damage to the eyes. Fortunately, this damage can be prevented by wearing the correct sunglasses.
The damage from harmful UVA and UVB radiation is cumulative over a person's lifetime and may contribute to serious age-related diseases of the eye and sensitive areas around the eye. Because the damage is cumulative, it is important to protect eyes from an early age in all light conditions.
In this section we will focus on the importance of protecting our eyes on the road and provide suggestions on how the correct measures might improve safety on the road.
Exposure to the Sun and Damage to the Eyes
Studies have shown that permanent damage to the eyes can result from prolonged exposure to the sun without adequate protection. It is important to understand this damage and we would like to provide a summary of findings from research studies:
- Ultra violet (UV) light is the component of sunlight most responsible for eye damage. Excessive exposure, especially from light reflected from sand, snow or pavement, can produce a burn on the surface of the eye which is usually painful, but temporary.
- UV rays carry more energy than visible light rays, so the eye is at greater risk of damage from absorbing UV radiation than from absorbing other kinds of light.
- Too much unprotected exposure to ultraviolet radiation (UV) can cause "photokeratitis." Just like sunburn on our skin, photokeratitis is sunburn of the eye. It hurts, makes the eyes red, sensitive to light and tearful.
- Of more concern is the cumulative damage of repeated exposure that may contribute to chronic eye disease.
- When your eyes absorb light, the process creates heat or chemical reactions in eye tissue. These reactions can cause permanent damage if the eye's natural ability to heal itself is overwhelmed.
- UV exposure can affect not only its surface, but also its internal structures (the lens and retina).
- UV light is a risk factor in the development of pterygium (a growth that invades the corner of the eyes), cataracts (clouding of the lens) and macular degeneration (breakdown of the macula).
- If eyes are overexposed to ultraviolet radiation, the front portion of the eyes may be damaged.
- If visible light is too bright or intense, or if you stare directly at the sun, even briefly, the retina can be damaged, causing permanent loss of vision.
- There are two types of UV rays that reach the Earth's surface: UVA and UVB. These rays can cause, or speed up the progress of several diseases that affect the eye or its supporting structures.
Risks to the Eyes from Sun Glare
It is essential to wear the correct eye protection when driving in sunny weather. The most dangerous conditions are caused by glare resulting from intense sunlight – reflected from the road surface, the bonnet, windscreen or dashboard of your car. This is the most common and dangerous visual problem when driving, outside of simply uncorrected vision.
Many sun glare accidents happen in the early morning or late afternoon, when the sun is on the horizon and little protection is offered by a car’s sun visor. Unfortunately, these times coincide perfectly with rush hour and the beginning of school days, making accidents more likely.
Glare is a distracting and sometimes dangerous excess of bright light, and can happen day or night. Glare is bothersome and discomforting; causing your eyes to work even harder. Your pupils contract, your eyelids narrow and the muscles around your eyes contract. Your eyes must strain to see well, causing squinting, eye fatigue, and in extreme cases, even temporary blindness. In daylight, glare can occur when walking indoors to outdoors, moving from shade to sunlight, even from reflected light off of surfaces like cars or sidewalks. At night, glare can occur from oncoming headlights while driving, or from bright reflections off of wet roads, even signs.
Blue light is visible light in the blue portion of the colour spectrum. The intense glare of light reflecting off snow or water contains blue light. Your eyes cannot focus clearly in blue light. Some scientists believe that routine exposure to blue light over many years may age the retina and increase the risk of blindness in some people over the age of sixty.
Accidents due to sun glare occur frequently—there is however a simple way to help prevent this. Polarized sunglasses are available from your eye doctor and not only protect your eyes from dangerous UV rays, but also protect you from the dangers of sun glare.
Eye Care and Safe Driving
Most accidents occur within three seconds of some form of distraction. This includes cell phones, adjusting the radio, dashboard dining, changing the heating or air conditioning, smoking, personal grooming, driving when tired -- and sun glare. According to the Vision Council of America, the sun is one of the most overlooked dangers while driving, particularly during the height of morning and afternoon travel. Thousands of people are injured each year, some fatally, as a result of sun glare.
What can we expect from our drivers?
- As a minimum legal requirement, motorists must be able to read a number plate from a distance of 20.5 metres (67 feet) and have a 120 degree wide field of view.
- This test is normally only carried out officially at the time of the driving test itself and research has shown that more than 10 per cent of drivers would fail a driving test if they re-took it today because of poor eyesight.
- It is a driver's responsibility to ensure that he can pass the number plate test at all times.
- You must also be able to see clearly out of the corners of your eyes, see clearly at night and not have double vision. It's important to remember that if you fail to meet these visual standards you are breaking the law every time you start your engine.
- If you need to wear prescription glasses to drive, never replace them with non-prescription sunglasses when it is sunny. Instead, get a pair of prescription sunglasses (which need look no different to normal sunglasses) or clip-on lenses over your prescription lenses.
- Every day tens of thousands of motorists drive without their glasses because of vanity, because they have forgotten them, or because they are only driving a short distance.
- No matter what the reason, these people are breaking the law and are a potential danger to themselves and other road users.
- It is a good idea to keep a spare pair of glasses in the vehicle so that you are never tempted to drive illegally without them.
It is important for drivers to be aware of changes in their eyesight and to have a regular eye examination (at least every two years).
When selecting sunglasses, drivers need to consider how they will be used. Wearing driving lenses that are too dark can cause visibility problems when driving from very bright conditions into shady-dark areas; driving into a tunnel could cause complete loss of vision.
Sunglasses and Driving at Night
Many drivers have difficulty driving at night, when the light from streetlights, oncoming headlights, and other light sources may reflect from the street surface and present a serious visibility problem. Often the glare is merely distracting, but it can be quite dangerous. Rainy weather can make night driving even more hazardous, as the wet streets and sidewalks reflect even more light than usual.
Wearing sunglasses during the day can help your night driving. Exposure to strong sunlight without adequate glare protection can sharply reduce your night vision. Even a few hours of exposure can slow your eyes' adaptation process as darkness falls.
A part of the driving population also suffers from "night myopia," when lack of light can cause difficulty in focusing on distant objects. Motorcycle riders must wear protective lenses at all times, so night-driving lenses, can be quite appealing to them.
Most reliable sources in the eye-care industry warn strongly against the wearing of sunglasses for night driving. The Sunglass Association of America, states: "So-called night-driving glasses are generally amber-tinted eyewear meant to reduce the glare of oncoming headlights. While they may make the driver feel more comfortable, they also reduce the wearer's visibility...."
Many studies have shown that "night-driving lenses" do not improve night-vision, and some have suggested that such lenses actually impair visual performance and make it more difficult for the eyes to compensate for glare.
UV protection claims are not valid for night-time driving, as the absence of sunlight means that there is no UV light to filter out. Similarly, polarized lenses are not advantageous at night, as night-time glare is not polarized like daytime, sunlight glare.
How can drivers improve their Night Driving Vision?
- Make sure that your windscreen is clean and streak-free on both the inside and outside surfaces.
- Particles of dust and dirt cause light waves to scatter, causing a halo-effect, and making glare seem worse.
- Make sure that any glasses that you are wearing are clean on both surfaces.
- Lenses worn at night should be clear and should have an anti-reflective coating applied to the lenses, as anti-reflective coatings can help combat internal reflections (which can contribute to the "halo effect") and they increase the flow of light through the lens to the eye.
- Make certain that your headlights are clean and properly aligned so that they do not create an undesirable glare in front of you.
Have a complete eye examination so that your ophthalmologist or optometrist can rule out cataracts or night myopia. If you have night myopia, your eye care practitioner can recommend the proper prescription lenses to correct your night vision and make night driving safer for you.
Eye Care and Selecting the Correct Sunglasses
Sunglasses, sunglasses, sunglasses.
Sunglasses are most important to help us see comfortably and clearly in sunlight and to protect our eyes from the threat of permanent damage that could lead to cataracts and other eye diseases. Good, top quality sunglasses provide comfort and complete protection even during lengthy exposure to harsh glare.
With or without a prescription, sunglasses that can block out nearly all UV rays are now readily available, protecting the eyes and significantly reducing the risk of vision problems caused by sunlight.
What should we look for in Sunglasses to protect our eyes?
- The best sunglasses are those purchased from an optician. This ensures the sunglasses have the appropriate amounts of UV filtering and are the best protection for your eyes while in the sun.
- You cannot tell how much UV protection a pair of sunglasses will provide by their price, colour, or by the darkness of the lenses.
- Look for a label that lists the type and amount of protection to make sure that they are coated and block both types of UV radiation: UVA and UVB.
- Look for sunglasses that block at least 99% of ultraviolet rays.
- When the visible light rays are cut out, your pupil will dilate in order to allow more light into your visual system. If they are not UV protected, the sunglasses are actually doing more harm than good
- Make sure the lenses are dark enough to keep your eyes comfortable, but not so dark that they reduce your vision.
- Demand good optical quality where the lens is free from distortion. Lines reflected in the lens will follow in straight lines the even contours of the lens, versus wavy, eye-straining distortions found in non-optical lenses.
- Another way to help protect your eyes from UV rays is to wear photochromic lenses, which are eyeglass lenses that darken when exposed to UV light.
- Photochromics is a good choice for everyday lenses because they automatically protect against UV. [ It is important to understand that not all plastic photochromic lenses block 100% UVA and UVB radiation]
- Polarizing lenses are designed to cut glare due to reflection. This means they are good for driving and outdoor activities in the snow or on water.
- Buying sunglasses from street vendors is risky. There's no assurance that the eyewear, no matter how dark the lens, will protect against UV rays.
There are many different types of sunglasses available. Best advice is to contact a registered optometrist and ask for advice. Do not gamble on the care and protection of your eyes!
General Safety Advice for Eye Protection/ Eye Care
Protecting your eyes does not have to depend on a new pair of sunglasses. There are also basic safety suggestions for our drivers:
- Protect your eyes by wearing a wide-brimmed hat or visor when you are out in bright sunlight
- DO NOT look at directly to the sun rays or Ultra Violet Rays of the sun.
- Ensure that your windscreen is clean and scratch-free, both inside and out, at all times.
- Make sure that the headlight glass is clean, the bulbs are working at full strength and your lights are properly adjusted to provide good road illumination while not causing glare for other road users.
- Look slightly to the left of oncoming traffic at night to avoid suffering from glare which can take some time to recover from.
- Remove all non-essential stickers from the windows of your vehicle, or hanging objects where they might prove a distraction and obstruct your view.
- In high glare situations, bring your sun visor down, and pull out the extension, if there is one.
- If your visor is broken, have it fixed or replaced. Remember that your visor can also be turned to cover the side window.
- Give your eyes a break - Stop more often during sunny conditions and rest your eyes for about five minutes.
- Keep a lens cloth in your vehicle along with your spare pair of glasses.
- Glasses and contact lenses should be kept clean to ensure a clear field of vision.
- Wearers of contact lenses, and sufferers from hay fever, should also keep a spare pair of glasses in the auto.
- Switching to a pair of glasses when travelling long distances offers some respite for tired, watery eyes.
Therefore, be sure to always care for your eyes – you need them to look out for you!