By The Eye desk · Last verified 4 October 2026
When you buy sunglasses, three labels matter. UV400 means the lenses block ultraviolet light at wavelengths up to 400 nanometres, which covers both UVA and UVB; this is the protection for your eyes. Polarised means a filter that cuts reflected glare from water, roads and car bonnets; it improves comfort but is not UV protection by itself. The filter category, from 0 to 4, tells you how dark the lens is; category 4 is too dark for driving. Darkness and price say nothing about UV. In Singapore, where NEA notes the UV index commonly reaches Very High or Extreme between 11am and 3pm, UV400 is the label to look for first.
Good news: proper protection is not a luxury feature. Once you know what the stickers mean, you can buy with confidence at any price point, and spend the extra only on what you will enjoy.
Quick facts
- UV400 blocks UV wavelengths up to 400nm, covering UVA and UVB; “100% UV protection” is the same promise in different words.
- Polarisation reduces glare from flat, shiny surfaces; it does not guarantee UV protection unless the lens is also UV400.
- A dark lens without UV protection can be worse than none, because your pupils widen behind it.
- Filter categories run 0 to 4 under ISO 12312-1; categories 0 to 3 are suitable for driving in daylight, category 4 is not.
- Lenses that let through less than 75% of light, which includes categories 2 to 4, are not suitable for driving at dusk or night.
- Prescription sunglasses start with an eye test by a registered optometrist or qualified optician in Singapore.
UV400, polarised and tint: what each label does
| Label | What it does | What it does not do |
|---|---|---|
| UV400 / 100% UV | Blocks UVA and UVB up to 400nm, protecting eyes and eyelid skin | Does not reduce glare or brightness on its own; clear lenses can be UV400 |
| Polarised | Cuts horizontal reflected glare from water, wet roads and windscreens | Not a UV rating; can make phone, ATM and some car dashboard screens look dark or patchy |
| Tint category 0 to 4 | Shows how much visible light passes through | Says nothing about UV; darker is not safer |
| Photochromic | Darkens in UV light and clears indoors | Often darkens less inside a car, because windscreens filter much of the UV that triggers it |
| Mirror or gradient coating | Reduces brightness or shades the top of your view | Not a UV rating either |
Which tint category for Singapore?
The international sunglasses standard sorts lenses by how much visible light they let through. The College of Optometrists, citing the standard, sets out the bands below. For a bright equatorial city, category 2 or 3 suits most everyday wear.
| Category | Light let through | Good for | Driving |
|---|---|---|---|
| 0 | 80% to 100% | Fashion, indoors, clear UV400 lenses | Yes |
| 1 | 43% to 80% | Cloudy days, light tints | Yes |
| 2 | 18% to 43% | Everyday city use | Yes, daytime only |
| 3 | 8% to 18% | Strong sun, beach, sea | Yes, daytime only |
| 4 | 3% to 8% | Glaciers, high mountains, very intense glare | No |
Category is usually printed inside the arm or on the swing tag, often as “Cat. 3” next to the CE mark. If a pair has no category and no UV information at all, treat that as a warning sign.
Prescription sunglasses: your options
If you wear glasses, start with a current prescription, then choose among tinted lenses, photochromics and clip-ons. Most optical shops in Singapore can make tinted prescription lenses, with or without polarisation, in most frames that suit your prescription.
- Get a current prescription. Optometrists can examine eyes and prescribe glasses for all ages; some registered opticians can do refraction for patients aged 8 and above. Ask to see their registration and practising certificates, or check the Optometrists and Opticians Board register.
- Choose prescription tinted lenses in a sunglass frame; ask for UV400, the tint category and whether polarisation is included.
- Consider photochromic lenses if you want one pair for indoors and out, knowing they may darken less in a car.
- Try clip-ons or fit-overs as a low-cost option that sits on top of your usual glasses.
- Check strong or wraparound prescriptions early. Very curved frames can distort high prescriptions, so the optician may suggest a flatter style.
Contact lens wearers can simply wear non-prescription UV400 sunglasses on top. Some contact lenses carry UV blocking, but they do not cover the whites of the eyes or the eyelids, so sunglasses still help.
How to check a pair before you pay
Look for UV400 or 100% UVA/UVB on the lens sticker, tag or arm. Tilt the glasses while looking at a phone screen: if the screen darkens at an angle, the lens is polarised. Look through the lens at a straight line and move it slowly; a wobbly line suggests poor optical quality. Many optical shops have a UV meter and will test a pair for you. If a branded pair is priced far below normal, remember that counterfeits may carry fake labels too.
The WahLiao Verdict
Buy UV400 first, then pick the tint and style you love. For Singapore streets, a category 2 or 3 lens does the job; add polarisation if you drive a lot, fish, sail or spend weekends at the beach, and skip it if you squint at screens all day. If you need a prescription, get a fresh eye test and let a registered optician do the rest. Protection is cheap; looking good is the fun part.
Questions people ask
Are cheap sunglasses safe?
They can be, if they are properly labelled UV400 or 100% UV and come from a seller you trust. Price buys frame quality, optics and brand, not necessarily better UV protection.
Is polarised better than non-polarised?
Better for glare, not for UV. Polarised lenses are lovely on water and wet roads, but can make LCD screens hard to read, so some pilots and screen-heavy users prefer non-polarised.
Can I drive in very dark sunglasses?
Not category 4. Under the international standard, categories 0 to 3 are suitable for daytime driving, but any lens letting through less than 75% of light, which covers categories 2 to 4 and darker category 1 tints, is unsuitable at dusk or night.
Do children need sunglasses?
Children spend a lot of time outdoors, and UV400 sunglasses with a wide-brimmed hat are a sensible pair for beach days and midday play. A comfortable, flexible frame matters more than the brand.
Sources: National Environment Agency, UV index and Singapore’s midday UV levels; The College of Optometrists, filter categories and driving under ISO 12312-1; All About Vision, what UV400 means and polarisation; Optometrists and Opticians Board, who can test eyes and prescribe in Singapore. The Eye explains; it does not endorse.
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