Lenses & Coatings

A coloured lens signals mood and attitude before it signals anything functional — grey and green read as understated and serious, brown reads as warm and casual, and anything saturated (yellow, pink, blue) reads as a fashion choice first. None of this tells you how protected your eyes are, which comes down to a UV … Read more

A scratched lens cannot be repaired in any meaningful sense — the mark is a small loss of surface material, not something that can be filled back in. Polishing kits and home remedies can sometimes reduce how visible a light scratch looks, but they thin the lens surface to do it, and often make things … Read more

Coatings craze because the coating and the lens underneath expand, contract and age at different rates. A sudden temperature change, a harsh chemical, or simply years of wear can crack the thin coating layer into a fine, web-like pattern. Once that cracking has started, it cannot be polished away or reversed — the coating, or … Read more

A microfibre cloth used with a proper lens spray, or lukewarm water with a trace of washing-up liquid, rinsed off completely and dried with a clean microfibre cloth. That is it. Nothing abrasive, nothing with alcohol or ammonia in it, and nothing dry rubbed straight onto the lens — that last habit is what turns … Read more

Lens distortion at the edges happens because a lens is curved and thickest away from its optical centre, and light bends differently the further it travels from that centre. Bigger lenses, stronger prescriptions, and lenses cut off-centre from their blank all make the effect more visible toward the rim. It shows up as a faint … Read more

A lenticular lens is a lens with two zones: a small, optically active circle or oval in the centre that does the actual correcting, and a thinner, much less powerful “carrier” area around it that exists purely to fill the frame and hold everything in place. It’s a design used for very strong prescriptions, where … Read more

Strong prescriptions bend light before it reaches the eye, and that bending changes the size of the image a viewer sees — not the eye itself. Minus lenses, for shortsightedness, shrink the eye behind them. Plus lenses, for longsightedness, magnify it. The stronger the prescription, the more pronounced the effect. What actually causes the minification … Read more

Base curve is the curvature of a lens’s front surface — how steeply it bows outward, measured on a standard scale rather than as a specific power. A flatter base curve sits closer to the face and looks more restrained; a steeper one wraps further around, which is why sports and wrap sunglasses look so … Read more

What is lens decentration? Decentration is the distance between a lens’s optical centre — the single point where it corrects vision with no distortion — and the centre of the pupil when the glasses are worn. Every prescription lens is made with an optical centre in a fixed spot; decentration is how far that spot … Read more

No lens is perfectly colourless. Every “clear” lens is a stack of materials — the base plastic or glass, plus anti-reflective, scratch-resistant and oleophobic coatings — and each of those layers absorbs or reflects a tiny amount of light unevenly across the visible spectrum. What’s left over reads as a faint tint, usually green, blue … Read more