Sunglasses get shopped for like an accessory and worn like protective equipment. Both things are true, but only one of them shows up in the label.
Tint darkness tells you almost nothing about how well a pair shields your eyes. That job belongs to the ultraviolet filter, which is invisible and has to be stated by the seller. A very dark lens with no UV filter is arguably worse than no sunglasses at all, because your pupils open wider behind it and let more ultraviolet reach the back of the eye.
So: the protection question first, then the styles, then the part that decides whether you keep wearing them.
The only specification that is not negotiable
Look for lenses that block essentially all UVA and UVB, usually described as 100 percent UV protection or UV400. This is standard on reputable eyewear and costs very little to include, so there is no reason to accept less.
Over years, ultraviolet exposure is associated with cataract, growths on the surface of the eye, and damage to the eyelid skin. Short, intense exposure has its own risk: sun reflected off water, snow or sand can cause a painful surface burn of the cornea that shows up hours later. Children are worth protecting early, since they tend to be outdoors more.
Two more things that are not on the tag. Wider lenses and frames that curve toward your temples cut down light sneaking in at the sides. And a hat with a brim does a surprising amount of the work that sunglasses cannot.
The styles, briefly
Most sunglasses are a familiar shape with a tint in it. The vocabulary is worth knowing mainly so you can say what you want.
- Rectangular: wider than tall, corners sharp or softened. The quiet default.
- Square: blockier, roughly equal in height and width, often with gentler corners than the name suggests.
- Round: from thin vintage wire circles to thick modern plastic.
- Cat-eye: lifted outer corners, frequently paired with a colored frame.
- Aviator: teardrop lenses in light metal with generous coverage.
- Browline: a bold upper rim with a thin or missing lower one.
- Geometric: hexagons, octagons and other deliberate angles.
- Oversized: bigger in every direction, which happens to block more light.
- Wraparound: curved close to the head, the usual choice for running, cycling and skiing.
- Shield: one continuous lens across both eyes.
You will also see details described as though they were styles. A keyhole bridge is a small notch above the nose that changes how the frame sits. A brow bar is a straight bar running across the top between the lenses. Both are worth noticing because the bridge design affects fit more than looks.
Tint, polarization and mirrors
Once UV protection is settled, the lens choices are about comfort rather than safety.
- Gray keeps colors looking close to natural and is a safe all-purpose tint.
- Brown and amber lift contrast, which many people prefer for driving and for overcast days.
- Green sits between the two.
- Polarized lenses cut glare bouncing off flat surfaces such as wet roads and water. Useful for driving and fishing, though they can make some phone, dashboard and aircraft screens look dim or patchy.
- Mirror coatings reduce how much light gets through and are common in bright, high-altitude conditions.
- Photochromic lenses darken in sunlight and clear indoors. Handy, but many do not darken fully behind a car windshield, so they are not a reliable substitute for real sunglasses when driving.
Sunglasses have to fit too
Fit gets ignored more with sunglasses than with everyday glasses, which is why so many pairs end up pushed onto a head instead of a face.
The frame should be about as wide as your face, with the arms running straight back and bending only after they clear your ears. The bridge carries the weight, so it needs to match your nose: too wide and the pair slides down every time you look at your phone, too narrow and it presses. Lenses should not rest against your cheeks, or they will smudge constantly and push the frame out of place.
Any optical shop can adjust sunglasses, including a pair you bought elsewhere, and it usually takes a couple of minutes. It is the cheapest improvement available to a pair you already own.
If you need a prescription in your sunglasses
There are several routes, and the right one depends on how you spend your time.
A dedicated prescription pair works best and looks best, though it is a second purchase. Clip-ons and magnetic fronts turn one frame into two and travel well, at the cost of a little bulk. Photochromic lenses in your everyday glasses cover incidental sun without a second pair, but not the windshield problem. Some people simply wear contact lenses with non-prescription sunglasses, which brings its own care routine and risks, and is a conversation for your eye doctor rather than a default.
Vision plans sometimes let you apply a frame or lens allowance toward prescription sunglasses instead of a second clear pair. It is worth asking before you assume it is out of pocket.
Common questions
Do expensive sunglasses protect better?
Not necessarily. UV protection is inexpensive to build in, and an affordable pair labeled for full UV blocking does that job. Price tends to buy optical clarity, materials, durability and design.
Are polarized lenses always the better choice?
They are excellent against glare from roads and water, but they can wash out some digital displays. If that matters for your work, try a pair before committing.
Should I wear sunglasses on cloudy days?
Ultraviolet passes through cloud, so it is reasonable, especially near water or snow. Comfort can guide you on the tint, but the UV filter is the part doing the protecting.
Buy the shape that makes you happy, confirm the UV rating before anything else, and get the frame sitting properly on your face. If you would rather have someone check the fit and your prescription options in person, you can find an eye care provider who works with your vision plan and sort both out in one visit.