The four specs, in the order that matters
1. A stated UV rating — which is not the darkness
These are two different measurements, tested separately. The FDA’s sunglasses device page points at the ANSI Z80.3 and ISO 8980-3 standards for ultraviolet and for light transmittance as distinct specifications, which is the technical version of what its consumer page says plainly: pick 100% UV, and do not treat dark as protective. Prevent Blindness puts the shopping rule at its simplest — buy only sunglasses that carry a clear statement of UV blocking, and look for 99–100% of UVA and UVB. The CDC uses the same numbers.
Practically: if the listing does not say, assume it does not. Four of the five picks below state a rating. The one that does not is the Julbo Camino, whose listing states a filter category and a lens family but no UV figure for that SKU, and its card says “Not published” rather than quietly implying a number. Our guide to UV testing covers what to do about a pair you already own, and the short version is that an optical shop with a UV meter is the only reliable answer.
2. Polarization, if the light is bouncing off something
Brightness and glare are different complaints and need different fixes. A polarizing filter removes the horizontally-reflected light coming off water, wet roads, car bonnets and snow — the AAO describes polarization as the feature that addresses reflected daytime glare, and Maui Jim claims its own film eliminates 99.9% of it. Darkening a lens reduces everything equally, including the light you need.
If your “too bright” is a white road surface at midday or sun on water, polarization will do more for you than two filter categories of darkness. If it is open sky with nothing reflective in front of you, it does less. The two places to skip it are a cockpit instrument panel and, mildly, phone screens — polarized lenses and screens covers that trade, and polarized vs non-polarized covers the whole decision.
3. Coverage: light that arrives around the lens
A lens only filters the light that goes through it. The AAO’s advice on frame choice is to pick wraparound or oversized frames so that light cannot arrive from the sides or above, and the FDA repeats the wraparound point. In genuinely intense light this is the upgrade people notice most and buy least — squinting is usually a coverage problem, not a tint problem.
Three routes to it: a wrapped sport frame, a physically large frame, or a fit-over with side lenses. All three are on this site — wraparound, oversized and fit-over— and a brimmed hat is the fourth, costs nothing extra and is more effective than another category of tint.
4. Darkness, and the mirror coating
Now the one you came for. Filter category describes how much visible light reaches your eye: category 0 passes 80–100%, category 3 passes 8–18%, and category 4 passes under 8%. Category 3 is the right answer for nearly everyone in nearly all ordinary bright conditions, including the brightest summer day in an open landscape.
A mirror coating sits on top of the tint and reflects a further share of light away before it enters the lens, so a mirrored category 3 is a genuinely useful half-step without taking you somewhere you cannot drive. That is the argument for pick two, whose listing states a gray-blue mirror. Our mirrored sunglasses explainer covers what the coating does and does not do.
Category 4 is a different proposition and deserves its warning. It is sold for snow and altitude, it is commonly marked as unsuitable for driving, and it will leave you under-sighted walking into a shaded car park. If you genuinely need it — glacier travel, sustained time on snow — buy it from our glacier glasses page, where the whole page is built around that case, and carry an ordinary second pair.
If it is bright enough to hurt, read this first
There is a line between “bright” and a symptom. The AAO’s page on photophobia lists a light-coloured iris, reduced body pigmentation, ocular albinism and poor pupil contraction among the causes of raised light sensitivity, and notes that affected people can often be helped with tinted lenses or gradient tints that are darker at the top of the lens than the bottom. That is a prescription-counter conversation, not a shopping decision.
If light has recently become painful, if one eye is worse than the other, or if it comes with headaches or blurring, see an eye doctor rather than buying a darker lens — a darker lens is the one purchase that can mask a change worth investigating. We have two pages for the in-between cases: sunglasses for light sensitivity and why sunglasses give you a headache, which is more often a fit problem than a lens one.
What we checked and did not feature
Very dark fashion lenses with no stated category or UV figure. The largest group in this corner of the market and the easiest to reject. A lens sold on looking almost black, with no filter category and no UV rating, is the exact combination every authority on this page warns about. There is no version of this page where that product is a pick.
A second category 4 frame.Our registry carries a budget category 4 with side shields, and it is a sensible buy — for snow. On a page about ordinary bright daylight, a second frame you cannot legally drive in would be padding, so it stays on the glacier page with the rest of that family.
Clip-ons, for the glasses-wearing version of this problem. A polarized clip-on over your own prescription frames is the cheapest route to a dark lens if you already wear glasses, and it beats a fit-over on bulk. It loses on coverage, which is criterion three on this page, so the fit-over took the slot — our clip-on roundup ranks them properly.
The opposite condition is less obvious and more often skipped: do you need sunglasses on cloudy days explains why cloud cuts brightness far more than it cuts ultraviolet.
