Eyewear, explained
An anti-reflective coating is a microscopically thin layer applied to the front and back of a lens that stops light bouncing straight back off the glass or plastic. Less light reflects, so more of it passes through to the eye — the lens looks clearer, and other people can actually see your eyes rather than … Read more
Photochromic lenses darken by reacting to UV light, and most car windscreens are laminated in a way that blocks the majority of UV before it ever reaches the lens. No UV trigger, no strong reaction. That’s why a pair that goes convincingly dark on a bright pavement can stay stubbornly pale behind the wheel. What … Read more
Photochromic lenses are clear (or nearly clear) indoors and darken automatically when exposed to UV light outdoors, then fade back as UV drops. The reaction is triggered by ultraviolet radiation, not visible brightness — which is exactly why they struggle behind glass, in a heated car, or in very cold weather. What are photochromic lenses, … Read more
Both, but not equally. Lens colour genuinely changes what reaches your eye — it can shift contrast, warm or cool a scene, and make edges feel sharper or flatter. It does not, on its own, determine how well your eyes are protected from UV, and it rarely changes your actual vision the way a prescription … Read more
A gradient lens is tinted darkest at the top and fades to little or no colour towards the bottom. It exists mainly to cut glare from overhead sun and reflective surfaces while keeping the lower field of vision clearer — useful for driving, reading a phone, or checking a menu without lifting the glasses. The … Read more
A mirrored lens has a wafer-thin metallic coating applied to its front surface, so a portion of visible light bounces straight back off the lens instead of passing through. It cuts the glare that reaches the eye and gives the lens a reflective, often coloured, surface — but the coating itself does not determine how … Read more
Sunglass lens category numbers, from 0 to 4, describe how dark a tint is — nothing more. Category 0 is barely tinted, category 4 is very dark and unsuitable for driving. The number has no bearing on UV protection, which is a separate rating entirely, usually shown as UV400. What do the category numbers actually … Read more
Polarised lenses are a bad idea whenever the situation depends on you reading a screen, an instrument panel, or an icy patch through glare. Polarisation works by blocking the horizontal glare that bounces off flat surfaces — water, tarmac, snow — but that same trick can hide useful information or wash out digital displays, which … Read more
Polarised lenses contain a chemical filter, embedded in or laminated onto the lens, that blocks horizontally oriented light waves — the kind that bounce off flat, reflective surfaces like water, wet tarmac, glass and car bonnets. That reflected glare normally arrives as an intense, uniform band; the filter absorbs most of it, so what reaches … Read more
About what you read here. Everything on The Designer Glasses is general information and our own editorial opinion. We research carefully and we say when the evidence is unclear, but we can be wrong, things change, and no article can know your particular situation. Please do your own research and make your own judgement rather than treating anything here as the final word. This is not medical advice, not a diagnosis, and not a substitute for speaking to an optometrist, optician or eye doctor about your own eyes, vision and eyewear. We are writers and researchers, not clinicians. We do not recommend prescription treatments or give doses. If something is painful, getting worse, or worrying you, please talk to a professional — going early is not an overreaction.