Good vision for safer roads

While there usually aren’t direct prescription laws for driving or riding, there are general ways to convert each area’s requirements.

In the United Kingdom, for example, you must be able to read a car number plate in daylight from 20 meters away — about five car lengths — either with or without glasses (or other correction). 

In an eye test, visual acuity of 0.5 (6/12) is required in both eyes, meaning you must be able to read at 6 meters away what a person with “normal” vision can read at 12 meters away. This equates to about 20/40 vision, two “steps” below 20/20 vision (6/6 in the UK).

In the eye prescription of a nearsighted person, 20/40 vision is represented by a diopter value of -0.75. Dioptres are usually listed on your prescription under “Sphere” or “Power.” 

Nearsighted people with dioptre values of 0.00, -0.25 or -0.50 have at least 20/30 vision and are not legally required to wear glasses. While 20/20 vision isn’t legally required, it will always provide the greatest driving safety.

Other parts of your prescription can be more difficult to decipher — people with astigmatism are one example. Additionally, testing requisites for farsightedness (long-sightedness) or presbyopia can vary. 

An optician will be happy to verify whether your vision meets the legal requirements for driving in your country.

Reduced night vision isn’t always caused by age, but it is one of the most common visual complaints people have as they get older. These changes can go hand in hand with presbyopia, a completely natural part of the ageing process that starts to affect vision around age 40. Difficulty seeing things close up is caused by the weakening eye muscles and a less flexible lens inside the eye.

As people age, their pupils also tend to be smaller and less reactive to light. Smaller pupils allow less light to enter the eye. This effect is more noticeable in low light such as driving at night.

A cloudier lens inside the eye can also be to blame, and if it becomes too opaque, a cataract can develop. People with untreated cataracts require an additional 0.35 seconds to react to driving events, increasing stopping distance by up to 12 metres (almost 40 feet) when travelling at 130 kilometres an hour (around 80 miles per hour).

If you have trouble seeing at night, the first step is to schedule an eye exam with your optician. While a more serious condition is unlikely, they’ll be able to rule out other ailments and suggest treatments that may be available.

If you struggle to see distant objects, you’re in good company. It’s estimated that around the world nearly 2 billion people have myopia, commonly called short-sightedness. Short-sighted people can see close-up objects more clearly, while distant objects appear blurry and hard to focus on.

Astigmatism, a common condition that involves the curvature of the eye, can also cause difficulty focusing on signs. This often results in slightly different vision in each eye and can occur alongside myopia.

Fortunately, myopia and astigmatism are almost always easy to treat. A brief eye test with your optician and a pair of glasses or contact lenses should provide clear vision.

Treating common vision problems is an easy way to maximize your safety on the road: Drivers with poor vision can take an additional 3 seconds to fully identify a road sign when travelling at 50 kilometres per hour (around 30 miles per hour).

If you’re driving at night and having trouble reading signs because of light reflected off of them, make sure your high beams aren’t on when they're not required. Not only can your high beams make it harder to read signs, but they also shine directly into the eyes of oncoming drivers, creating a blinding effect. If you wear glasses consider lenses that are optimised for night driving.

There’s a lot of information out there regarding which glasses are best for nighttime driving — it’s understandable if you’re unsure which ones to choose.

Amber-tinted “night driving glasses” are often advertised as a solution. However, research has shown that they are not always effective, and some lower-quality products may even result in worse night-driving vision. Their yellowish tint blocks headlights’ blue light, but further reduces contrast when contrast is already lowered — this can be hazardous. The same issue applies for tinted “shooter’s glasses,” which are often suggested as a more budget-friendly option.

Tinted lenses are categorized by the density of the tint — category 0 lenses are clear and category 4 lenses are so dark that only 3% - 8% of light can get through. Glasses tinted any darker than category 0 should not be worn when driving at night or in twilight hours because they can prevent too little light from getting to your eyes.

Instead, prescription glasses with an anti-reflective (AR) coating can reduce “internal” glare and reflections associated with nighttime driving. These glasses reduce or remove the visual disturbances associated with traditional, uncoated lenses, such as halos and light streaks.

Wearing AR lenses can reduce critical recovery times during night driving, in addition to improving vision sharpness and contrast.

The best way to decide what type of lenses to use — or not to use — when driving is to consult your optician because they are familiar with your unique vision needs and can recommend a solution that is best suited for you.

There’s a good chance you’ve experienced the distraction of headlights coming from oncoming traffic. If you’re travelling at 130 kilometres per hour (around 80 miles per hour) and your vision is affected by oncoming headlights, you may travel over 500 metres with limited vision. Some glasses can limit this effect, reducing eye strain and improving driving safety at night.

An anti-reflective (AR) coating can eliminate most reflections and significantly reduce the effects of glare on the road, providing the visual clarity and comfort you’ve been missing on your nighttime drives. Crizal Drive lenses, for example, can reduce reflections by 90% compared to standard lenses.

While polarised sunglasses are effective at reducing sunlight glare during the day, they are not recommended for reducing headlight glare at night. Yellow-tinted “night driving glasses” have not always been shown to benefit nighttime driving vision, and some lower-quality products may actually make vision worse.

Ask your optician what solutions they would recommend to reduce glare for your eyesight needs.

If you have glasses, wearing them when driving at night is a great way to maximize road safety. This is especially true for people with higher levels of myopia, hyperopia, astigmatism or presbyopia.

Driving with blurred vision is particularly dangerous at night due to lowered light and decreased contrast. Drivers with blurry vision are 2 to 4 times more likely to have a fatal crash at night than drivers with normal vision.

Wearing glasses with an anti-reflective (AR) coating designed specifically for nighttime driving provides the most benefit. Not only can this type of AR coating improve reaction times by reducing glare from headlights and street lamps it can also improve visual sharpness and contrast, both important during low-light driving.

Tinted “night driving glasses” are also on the market but have not always proved to help nighttime vision. The next time you see your optician, ask what you can do — and what solutions are available — to improve your eyesight when driving at night.

There’s a reason you should never drink and drive. Alcohol can have a significant effect on vision in addition to the many ways it impairs thinking and cognition. As a driver, alcohol consumption reduces visual focusing ability and reaction time.

There are small muscles in the eyes that constantly work to focus our vision. Alcohol affects muscle coordination and these eye muscles are no exception. As more alcohol is consumed and visual focusing becomes more impaired, people will experience increasingly blurred and double vision — especially hazardous when operating a vehicle at night.

Alcohol can also increase eye dryness, decrease peripheral vision (resulting in tunnel vision) and reduce the ability to differentiate between varying contrast levels — a key component of night vision. Distracting nighttime disturbances such as halos around headlights and street lamps have also been proven to increase with alcoholic consumption.

Driving starts with vision, and impairing this sense can have a domino effect on other parts of the body. Since cognitive performance and judgment also become impaired as alcohol consumption increases, it’s possible that the effects on vision may be dangerously underestimated.

The European Road Safety Observatory (ERSO) notes that preconceived notions about elderly drivers being unsafe are not necessarily true, and that driver safety “depends on the physical and mental condition of the individual.” Ageing eyesight is noted as one of the main physical traits that make older drivers more vulnerable.

ERSO has determined that “elderly drivers are more likely to hurt themselves than to put others at risk,” largely due to the physical vulnerability that comes with age. They found drivers over age 75  have 2 times the injury rate and 5 times the fatality rate as the average driver. These rates are roughly 3 to 7 times higher than the previous age group: drivers aged 65-74.

This is even more pronounced at night when decreased contrast sensitivity makes it harder to judge speed, distance and small details. Your pupils can shrink with age resulting in less light reaching your retinas, while more nighttime visual disturbances (such as halos and headlight glare) are noticeable.

In addition to more easily treatable eye conditions such as presbyopia, untreated cataracts can also add risk to driving. Drivers with cataracts are 2.5 times more likely to have previously been in a crash and take an extra 0.35 seconds to react on the road. At 130 kilometres per hour (around 81 miles per hour), this fraction of a second adds 12 metres to stopping distance.

Maintaining an up-to-date eye prescription and getting treatment for vision ailments ensures a safer journey for all ages.

If you are experiencing issues seeing close-up objects clearly, such as your sat nav it could be down to a common eye condition called hypermetropia. Hypermetropia affects the eye's ability to see objects close-up, but not object far away which is why it is also known as long-sightedness. If you've noticed this change in your eyesight visit your optician who will be able to determine if glasses are required.

If you’re over 40 years old and you’ve noticed increasing difficulty focusing on near objects, presbyopia could be to blame. Presbyopia, or age-related farsightedness, occurs gradually and naturally as your eyes weaken with age. But don’t worry, this happens to everyone as they get older.

This weakening of tiny muscles in our eyes results in trouble focusing on nearby objects. When you aren’t driving, you may find yourself holding your phone at arm’s length to read text messages and emails on your screen.

Presbyopia is usually easy to treat. Multifocal lenses like varifocals, bifocals or trifocals feature multiple magnification areas on each lens, providing clear vision at near, intermediate and far distances. Varifocal lenses simply remove the noticeable lines between each vision area, giving off a single-lens appearance to both the wearer and anyone looking at you.

Varifocal lenses are especially well-suited to driving since the dashboard and the distant road each fall directly within their respective viewing fields — distant focus at the top and near focus at the bottom.

Do you squint or strain your eyes to see when you are behind the wheel or scootering your way through the city? You may need glasses to see clearly all that’s ahead of you.

Blurry, unfocused vision is a symptom of all four of the most common and easily-correctable-with-glasses eye conditions: shortsightedness, farsightedness, astigmatism and presbyopia. 

You are definitely not alone. As many as 1 out of every 5 drivers (which means billions of people worldwide) cannot see the road clearly because of uncorrected vision issues. 

Here’s a closer look at how some of these common vision conditions can affect your road safety:

SHORTSIGHTEDNESS: Road signs in the distance appear blurry. How can this be a problem? If you can’t read the exit marker until too late, you’ll either cut over sharply (endangering yourself and others) or take the next exit and circle back. 

FARSIGHTEDNESS: Are you nearly out of petrol? Are you driving too fast? It may be difficult to read those dials on your dashboard. The road safety ramifications are obvious in this case: You may be stuck on the side of the lane or ticketed for speeding. 

With astigmatism, objects at near and far distances may look blurry.

With presbyopia, often called age-related nearsightedness, you will begin to have difficulty focusing on dashboards and other close-up objects starting around age 40.

The solution for each of these vision problems is a pair of glasses. See your eye care professional for an eye exam and prescription. 

Get the glasses you need to be able to see clearly out your windshield (to safely exit the highway) and to make out your dashboard dials (so you aren’t surprised to hear a siren behind you). 

Proper vision is critical to a safe driving or riding experience. Even a minor vision impairment can reduce reaction times during an activity when every moment matters. Adding just a fraction of a second to your reaction time can prevent an accident.

At night, uncorrected vision can become even more problematic — fatal crashes are 2 to 4 times more likely when the driver has blurry vision.

Wearing glasses with an anti-reflective (AR) coating improves reaction times by reducing lens glare from headlights and street lamps. AR lenses also improve visual sharpness and contrast, both essential for low-light driving.

Uncorrected vision problems can lead to difficulty reading road signs, especially for nearsighted people (also called myopic or shortsighted) who have trouble seeing objects far away.

This blurry vision can also affect pedestrians or runners struggling to read signals at street crossings.

Hyperopic (also called farsighted or long-sighted) and presbyopic drivers experience difficulty focusing on objects that are close to them, such as a map app on their smartphone or the dials and gauges on their dashboard, some of which require frequent monitoring.

Spending extra seconds squinting at your odometer, fuel gauge, stereo, temperature controls or GPS can distract your attention and reduce reaction time.

According to the World Health Organization, 80% of all vision impairments can be prevented, corrected or cured. With the help of an eye care professional, you can keep your eyes healthy and your vision corrected for a safer, more comfortable drive.