Sunglasses for Driving: Which Lens and Category to Choose?

Choosing sunglasses for driving is different from choosing a pair for the beach: the lens has to show the road, the traffic lights and the dashboard clearly, and it must not leave you in difficulty when the light changes. For daytime driving, a lens with UV protection and a category 2 or category 3 filter is suitable. Category 4 lenses, use at dusk and at night, and how polarised lenses interact with screens are the points that people most often mix up.

Which category should sunglasses for driving be?

Category 2 and category 3 sunglass lenses are used for daytime driving. The filter category is a number from 0 to 4 that shows how much visible light a lens lets through, and it is defined in EN ISO 12312-1, the standard for sunglasses. The higher the number, the darker the lens.

In Antalya the summer sun is strong in the middle of the day, and at those hours a category 3 lens suits an open road. Early in the morning, on partly cloudy days or on shaded roads, category 2 gives more balanced vision. On most sunglasses the category number is printed on the inside of the temple, next to the CE mark. The five categories are explained in detail in our article on sunglass filter categories.

Why are category 4 lenses not suitable for driving?

Category 4 lenses let through only 3-8% of visible light, so they are not suitable for driving or road use. These lenses are made for extremely bright environments such as high mountains and glaciers. Behind the wheel, however, the moment you enter shade, a tunnel or a tree-lined road, the road, pedestrians and other vehicles stay far too dark, and traffic lights and brake lights become hard to make out. The label or user information of these lenses usually carries a warning that they are not suitable for driving.

Which lens colour suits driving?

Grey, brown and gradient lenses are popular choices for driving. Grey does not change colours, brown increases contrast and a gradient lens keeps the dashboard easy to read. The lens colour shapes the character of your vision; it does not determine UV protection.

A mirror coating reflects part of the light that reaches the lens; it is not a colour but a layer added to the lens surface. Very bright fashion tints (blue, pink or red, for example) can change how you perceive traffic lights and warning lights, so they are used with caution when driving. You can find a detailed comparison of colours in our article on sunglass lens colours.

Do polarised lenses help when driving?

Yes, polarised lenses help in daytime driving because they reduce the glare reflected off wet roads and the bonnet of the car. A polarised lens is a lens with a filter layer that blocks the horizontally polarised light reflected off flat surfaces. Asphalt shining after rain, puddles at the roadside and your own bonnet look calmer through this filter.

The limits of polarised lenses when driving are:

1. Some dashboard displays, navigation screens and head-up displays can look faded, dark or tinted through a polarised lens.
2. A phone screen can go dark at certain angles; the image changes depending on whether you hold the phone horizontally or vertically.
3. Polarisation does not mean UV protection. The two are separate features, and one does not indicate the other.

So, if possible, it is a sensible check to try polarised glasses while looking at your own car's displays. To find out whether a lens is polarised, look at an LCD screen through the glasses and turn them 90 degrees; if the screen goes dark, the lens is polarised. The full topic is covered in our article what are polarised sunglasses.

Should you wear sunglasses at dusk or at night?

No, lenses with a light transmission below 75% are not worn when driving at dusk or at night. All category 2, 3 and 4 lenses, and most of the category 1 range, fall below this limit. You need to take your sunglasses off after sunset; as it gets dark, a tinted lens makes it harder to pick out the road, pedestrians and signs.

There is no scientific evidence that the yellow lenses sold for night driving improve vision. A yellow lens can give an impression of contrast in low light, but every tinted lens blocks part of the light reaching the eye. If oncoming headlights bother you noticeably or you find it hard to see in the dark, an ophthalmologist can assess the cause.

An anti-reflective coating, on the other hand, reduces reflections on the lens surface and cuts glare when driving at night; it is not a sun lens and is applied to clear lenses. More detail is in our article on lens coatings.

Why do photochromic lenses darken only slightly in the car?

Photochromic lenses darken only slightly in the car because the windscreen blocks most of the ultraviolet light that makes them darken. A photochromic lens darkens under UV and clears again indoors. A lens that turns dark outdoors can stay light behind the wheel; this is not a fault but the result of how the lens works. For this reason a photochromic lens cannot always replace sunglasses for driving.

What kind of frame suits driving?

A frame that suits driving does not block your side vision and stays steady on your face. What you see out of the corner of your eye matters when changing lanes, at junctions and when checking your mirrors; very thick temples and wide side pieces can narrow that field. Points to look out for:

1. The temples should be thin or of medium thickness and should not cut into your side vision at eye level.
2. The frame should not slide down your nose when you turn your head or look down.
3. The lenses should cover the area around the eyes well, so that light coming in from above and from the sides does not dazzle you.
4. The glasses should be light, so they do not press on your nose and behind your ears on long journeys.
5. The glasses should be easy to put on and take off, as you need to remove them in long tunnels and when it gets dark.

What options are there for people who wear prescription glasses?

The main options for drivers who wear prescription glasses are prescription sunglass lenses and clip-ons; photochromic lenses are of limited use when driving because they darken only slightly in the car. The table below is for information only; prescription lenses are supplied against a prescription written by an ophthalmologist.

The rule of avoiding very dark lenses for daytime driving and not wearing dark lenses at night applies to prescription sunglass lenses too. You can ask your ophthalmologist any questions about your prescription.

What should you check when choosing glasses for driving?

When choosing sunglasses for driving, check the UV protection, the category number, the lens colour and the field of view of the frame, in that order. The sequence below is a short checklist you can follow when you pick up a pair:

1. Look for the CE mark on the inside of the temple and the UV400 label on the tag or in the product information.
2. Confirm that the category number is 2 or 3; if it says 4, those glasses are not for driving.
3. Choose the lens colour for your use: grey for steady strong sun, brown for changing light, and a gradient if you check the dashboard often.
4. If you are considering polarised lenses, look at your car's dashboard and navigation screen through them.
5. Put the glasses on and turn your head left and right; the temples should not cut into your side vision.
6. Do not leave the glasses on the dashboard in the sun; in summer the high temperature inside a car can damage the coating and the frame.

In Antalya the sun is strong for most of the year, and on the roads around Belek and Kadriye, wet asphalt after rain and light reflected off the cars ahead increase glare. On roads like these, a category 3 lens for the daytime, in grey or brown and polarised if you prefer, plus a case to put the glasses in as it gets dark, meets the needs of most drivers.