The lens is where most of the money goes and where most of the confusion lives. This page explains the choices in ordinary language, so that when someone in a shop recommends something, you can judge for yourself whether it makes sense for you. Including when that someone is us.
The design determines where in the lens you can see clearly. Get this wrong and no amount of coating will rescue it.
One power across the whole lens. Corrects for one distance, either far or near. This is what most people under forty wear, and it is also what dedicated reading glasses are.
Best for: short sight, long sight, astigmatism, or reading only.
Two powers with a visible line between them. Distance above, reading below. Simple, cheap and reliable, with no intermediate zone, so a computer screen falls awkwardly between the two.
Best for: people who want a defined reading segment and do not use screens much.
Power changes gradually from distance at the top through intermediate to reading at the bottom, with no line. One pair covers everything, but the corridor is narrow and needs correct fitting heights.
Best for: anyone over forty who wants a single pair for everything.
Tuned for arm's length to across the room. Much wider comfortable zones than progressives at a desk, but useless for driving. A second pair, not a first.
Best for: long days at a computer, drafting tables, workshop benches.
If you are over forty and spend most of your working day at a screen, the honest answer is often progressives for general wear plus office lenses for the desk. Two pairs sounds like an upsell, which is exactly why we explain the reasoning rather than just recommending it.
Index is how strongly the material bends light. Higher index means a thinner, flatter lens for the same prescription. It is not a quality rating, and it is not always worth the money.
| Index | Roughly suits | Thickness | Worth it when |
|---|---|---|---|
| 1.50 CR-39 | Up to about ±2.00 | Standard | Mild prescriptions, large frames where weight is not an issue |
| 1.56 | Up to about ±3.00 | Slightly thinner | A modest step up at a modest price. A common sensible default |
| 1.59 polycarbonate | Up to about ±4.00 | Thin, very tough | Children, sports, rimless mounts. Impact resistance is the point |
| 1.60 | About ±3.00 to ±5.00 | Noticeably thinner | Where edge thickness has started to show in your current pair |
| 1.67 | About ±5.00 to ±7.00 | Considerably thinner | Strong prescriptions, and smaller frames that expose lens edges |
| 1.74 | Above about ±7.00 | Thinnest available | High prescriptions where every millimetre and gram counts |
If your prescription is mild, a high index lens will not look meaningfully different and you are paying for a number. If your prescription is strong, it changes how the glasses look on your face and how they feel by the end of the day, and it is money well spent.
Frame choice matters here too. A smaller frame edges a lens closer to its centre, so the edges stay thinner. A large frame with a strong prescription is where lenses start to look like bottle bases, whatever index you choose.
The prescription ranges above are working guidance, not rules. Astigmatism, the size and shape of the frame, and where your pupils sit within it all shift the answer, which is why we work it out on the actual frame you have picked rather than quoting a chart.
Ask to see the edge thickness estimate for your prescription in the frame you are considering. Any optician should be able to give you that, and it settles the question faster than any explanation.
Coatings are where the most upselling happens in optics. Here is what each one is for, and how much it matters.
| Coating | What it does | Our view |
|---|---|---|
| Anti-reflective | Cuts reflections off the lens surface, so more light reaches your eye and people can see your eyes | Worth it for almost everyone. The single biggest improvement per rupee, especially for night driving and screen work |
| Hard coat | Resists scratching on the lens surface | Standard on most modern lenses. Confirm it is included rather than paying separately |
| Hydrophobic and oleophobic | Repels water and skin oil, so lenses stay cleaner and wipe more easily | Usually bundled with a good anti-reflective coating. Genuinely useful in monsoon and dusty conditions |
| Blue filter | Reduces a portion of blue-violet light from screens and LED lighting | Some people report less eye strain, others notice nothing. Evidence is mixed. Worth trying if screens tire you, not worth insisting on |
| UV protection | Blocks ultraviolet light reaching the eye | Should be standard, not an extra. Check it is included in clear lenses as well as sunglasses |
| Anti-fog | Slows condensation on the lens surface | Useful if you wear a mask, cook, or move between air conditioning and the street. Wears off over time |
| Mirror coating | Reflective finish on sunglass lenses, reducing transmitted light further | Cosmetic and functional. Scratches show more readily than on plain tints |
A reasonable default for most people: a good anti-reflective coating with hard and hydrophobic layers, and UV protection included. Add anything else only if you can name the specific problem it solves for you.
Between glare off the road, dust, and long bright afternoons, the tint choice matters more here than the brochure suggests.
Filters horizontally reflected light, which is what glare off wet roads, car bonnets and water actually is. The improvement while driving is immediate and obvious. Slight downside: some phone and dashboard screens go dark at certain angles.
Uniform darkness across the lens, in whatever depth you choose. Cheaper than polarised and available in more colours. Reduces overall brightness but does nothing specific about reflected glare.
Dark at the top, clear towards the bottom. Shades against overhead sun while leaving your near vision usable, which makes them good in the city and poor at the beach.
Clear indoors, darkening in sunlight. One pair instead of two. They darken less inside a car, because windscreens block much of the ultraviolet that triggers them, so they are not a substitute for driving sunglasses.
Increases contrast and depth perception, which many drivers prefer. A good general purpose choice for Indian daylight and for dusty conditions.
Neutral, keeping colours closest to true. The safest choice if you dislike the way tinted lenses shift what you see, and the standard for general bright sunlight.
Darkness is not protection. A very dark lens without UV filtering is worse than no sunglasses at all, because your pupils open wider behind it. Every pair we sell blocks UV, and you should confirm the same anywhere else.
Four common situations, and where each one usually lands.
Anti-reflective coating is essential. If you are under forty, single vision with a good coating is usually enough. If you are over forty, office lenses at the desk plus progressives for everything else will be more comfortable than one pair trying to do both.
Polarised sunglasses for daytime, and anti-reflective coating on your clear glasses for night. The coating is what reduces the halos around oncoming headlights, and it is the change most drivers notice fastest.
Higher index earns its cost here, and frame choice matters as much as index. A smaller, well proportioned frame will do more for edge thickness than paying up one index step in a large frame.
Polycarbonate lenses for impact resistance, a flexible frame that springs back, and hard coating. Skip the expensive extras. Children outgrow prescriptions faster than lenses wear out, so build for survival and replace when the eyes change.
Most scratched lenses are scratched by their owners, usually in the same few ways.
Bring them in whenever they stop sitting right, whenever the vision seems less crisp than it was, or once every few months for a clean and tighten if nothing is obviously wrong. There is no charge for any of that, and it costs us five minutes.
Coatings typically hold up for two to three years of daily wear before they start to craze, sooner in dusty or humid conditions. Frames last considerably longer if the hinges are maintained. If your prescription is stable and your coating is deteriorating, reglazing your existing frame is usually the sensible move.
Ten minutes with the actual numbers and the actual frame will settle more than an hour of reading. Bring your current glasses too, they tell us a great deal.