Sun Protection — How to Choose Glasses That Actually Protect Your Eyes
Written by MODI
Sunglasses protect your eyes only if the lens carries a real ultraviolet filter. What matters is 100% UVA/UVB protection — often marked UV400 — not how dark the lens looks. A dark lens with no UV filter is genuinely worse than wearing nothing: the shade makes your pupil open wider, and a wider pupil lets more ultraviolet through to the inside of the eye.
That single fact is why cheap unmarked sunglasses are a bad idea, and why "very dark" is not a quality signal. Below: what UV actually does to the eye, how to read a lens spec, when polarization is worth it, and when Georgians need protection most.
What UVA and UVB actually do to the eye
Ultraviolet is the part of sunlight just beyond violet, invisible to us, and it is divided by wavelength. Both parts that reach the ground affect the eye, but differently.
UVB (roughly 280-315 nm) is mostly absorbed by the front of the eye — the cornea and the conjunctiva. A single intense exposure, typically a day on the water or on snow without protection, can cause photokeratitis: essentially sunburn of the cornea. It shows up hours later as burning, watering, light sensitivity and the feeling of sand in the eye. It heals, but it is genuinely painful. Long-term UVB exposure is also linked to pterygium, the fleshy growth on the white of the eye that people who work outdoors develop.
UVA (roughly 315-400 nm) penetrates deeper, reaching the crystalline lens and, in part, the retina. It causes no immediate pain, which is exactly the problem — the effect is cumulative over decades. Long-term UV exposure is one of the recognised risk factors for cataract, and is associated with age-related changes in the macula.
And there is the skin: the eyelids and the area around the eyes are thin, delicate skin that gets a lot of sun and rarely gets sunscreen. A frame with decent coverage helps there too.
Two things people get wrong. First, clouds are not a filter — a large share of UV passes straight through light cloud, which is why an overcast day at the sea still burns. Second, UV has nothing to do with heat or brightness. A cold, bright March day in the mountains can deliver more UV to your eyes than a hot August afternoon in the city.
Why a dark lens without a UV filter is worse than none
This is the most important paragraph in this article.
Your pupil reacts to visible light. In bright conditions it constricts, which mechanically limits how much of everything — including ultraviolet — enters the eye. Squinting does the same thing.
Put on a dark lens and the eye reads the scene as dim. The pupil dilates. You stop squinting. If that dark lens has no UV filter, you have just opened the door wider and removed the doorman: more ultraviolet reaches the lens and retina than if you had worn nothing at all.
The practical consequence: tint and UV protection are two independent properties of a lens. A completely clear lens can block 100% of UV. A near-black lens can block almost none. You cannot tell by looking, which is why the marking matters more than the shade.
How to tell whether a pair actually protects
- Look for an explicit claim: 100% UV protection, UV400, or 100% UVA/UVB. Vague wording like "UV protective" with no figure means nothing.
- Buy from a retailer that can tell you the lens specification, not from a street stall.
- Price is a weak signal in both directions — an expensive designer frame is not automatically better filtered, and a well-specified affordable lens can be excellent. The specification is the signal.
- UV filtering does not wear off with normal use, but a deeply scratched lens should be replaced — scratches scatter light and make you squint again.
What "100% UV400" actually means
UV400 means the lens blocks all wavelengths up to 400 nanometres. Since UVA tops out at about 400 nm and UVB sits well below it, blocking everything under 400 nm is the same thing as blocking 100% of the ultraviolet that reaches the eye. So UV400 and "100% UVA/UVB" describe the same level of protection, written two ways.
Worth separating from two other numbers people confuse it with:
- Darkness category. Sun lenses are graded by how much visible light they transmit, from very light to very dark. This is a comfort and glare scale — it says nothing about UV. A category 1 lens and a category 3 lens can both be UV400.
- Polarization. Also independent. A lens can be polarized without full UV protection, or UV400 without being polarized. Good sun lenses are both.
All BARNER sun lenses are TAC polarized with 100% UVA/UVB protection — the two properties together, which is what you want in a single pair.
Polarized, tinted or photochromic — which one
These three words describe three different jobs. Here is what each actually does:
| Simple tint | Polarized | Photochromic | |
|---|---|---|---|
| What it does | Reduces overall brightness evenly | Reduces brightness and additionally cancels light reflected off flat surfaces | Darkens in sunlight, clears indoors |
| Effect on glare | Dims glare along with everything else | Removes the reflected glare specifically — water, wet road, snow, car bonnets | Depends on the tint it reaches; no glare cancelling by itself |
| Best for | Everyday city wear, a lighter look | Sea, boats, snow, driving, fishing | One pair for indoors and out, changeable weather |
| Trade-off | Contrast stays flat in strong reflections | Some LCD screens and dashboards can look dark at certain angles | Takes time to change; darkens less behind a windscreen |
| UV protection | Only if specified separately | Only if specified separately | Only if specified separately |
Note the bottom row: none of the three implies UV protection on its own. Always check for the 100% UV / UV400 marking regardless of which type you choose.
We go deeper into each in Polarized Lenses: How They Work and When They Won't Help and "Chameleon" Glasses — What Photochromic Lenses Are.
When Georgians need sun protection most
The sea, in summer. Water reflects a large part of the light that hits it, so at Batumi, Kobuleti or Gonio your eyes take UV twice — once from the sky and once off the surface. Wet sand and pale concrete do the same. This is where polarization earns its keep: the reflected glare off water is exactly the light a polarized lens is built to cancel.
The mountains, in winter. Snow is the most reflective natural surface there is, sending back a large share of the UV that lands on it. Add altitude — UV intensity rises the higher you go — and a day at Gudauri or Bakuriani is one of the highest-UV situations you will encounter all year, including on cloudy days. Skiing without eye protection is how people end up with photokeratitis, sometimes called snow blindness.
Driving. A windscreen filters a good deal of UV, but side windows filter much less, and glare is a separate safety issue: low sun, wet asphalt after rain, and the bonnet of the car ahead all throw horizontal reflections straight into your eyes. A polarized lens cuts precisely that. One caution — with polarized lenses some dashboard and phone displays can go dark at certain head angles, so try them in the car before a long trip.
Children. The crystalline lens of a young eye is clearer than an adult's and lets more UV through to the retina, and children spend more hours outdoors than most adults. Proper UV-filtering sunglasses matter at least as much for them as for you.
If you are choosing your first serious pair, Choosing Sunglasses: Polarized Lenses and UV Protection walks through shapes and fit as well.
What MODI offers, and where to buy
MODI has been the official BARNER retailer in Georgia since September 2024. BARNER is a Barcelona brand, and its sun lenses are TAC polarized with 100% UVA/UVB protection as standard — you do not have to hunt for the specification model by model.
The frames themselves: TR-90, around 15 grams, which matters more than people expect on a long beach day; and bio-acetate for a more classic look. Adult frames start at 195 ₾, the kids' range from 140 ₾. If you need correction, prescription lenses can be fitted into a BARNER frame within a -4 to +4 range — tinted at 125 ₾, photochromic at 135 ₾, blue-light at 105 ₾.
Browse the sunglasses collection, or come and try frames on at any of our four stores, open daily 10:00-22:00:
- Vake — Axis Towers, 37a Chavchavadze Avenue
- East Point
- Tbilisi Mall
- Batumi Grand Mall
We deliver across Georgia, and installment payment is available.
Frequently asked questions
Does a darker lens mean better protection?
No. Darkness and UV filtering are independent properties. A dark lens without a UV filter is worse than no glasses, because the shade makes the pupil open wider and more ultraviolet reaches the inside of the eye. Look for the 100% UV or UV400 marking, not for the darkest tint.
What does UV400 mean?
It means the lens blocks every wavelength up to 400 nanometres. Since ultraviolet that reaches the eye tops out around 400 nm, UV400 and 100% UVA/UVB protection describe the same thing.
What is the difference between polarized and simply tinted lenses?
A tint reduces overall brightness. A polarized lens does that and additionally cancels light reflected off flat surfaces such as water, wet asphalt or snow, which removes glare rather than just dimming it. Neither implies UV protection on its own.
Do I need sunglasses in winter?
Yes, and in the mountains more than anywhere. Snow reflects a large share of the ultraviolet falling on it and UV intensity increases with altitude, so a day at Gudauri or Bakuriani can expose your eyes to more UV than a summer day in the city, including under cloud.
Can prescription lenses be fitted into sunglasses?
Yes. At MODI a BARNER frame can be fitted with prescription lenses in a -4 to +4 range: tinted 125 GEL, photochromic 135 GEL, blue-light 105 GEL. You need a current prescription from an ophthalmologist.
