1.6 vs 1.67 vs 1.74 lenses
Choose the option that solves your main buying risk first: price, fit, designer choice, support or reglazing. Do not treat both sides as equal.
Lens index verdict
Lens index is about material and thickness, not better eyesight. 1.6, 1.67 and 1.74 can make lenses thinner as prescriptions get stronger, but the right choice depends on prescription, frame size, comfort and budget.
Affiliate disclosure: Some retailer links on UK Glasses Guide may earn commission at no extra cost to you. We still explain caveats, alternatives and buyer checks before linking out.
Buyers comparing lens thinning upgrades and trying to understand whether the extra spend is justified.
Very strong prescriptions, prism, varifocals and unusual frame choices should be checked with an optician or lens specialist.
Look at prescription strength, frame size, expected edge thickness, coatings and the retailer explanation. Do not upgrade purely because the option sounds premium.
How to think about lens index choices before ordering
The useful starting point is not the cheapest advertised frame. It is the finished pair that will arrive with the right prescription, the right lens design, a frame that fits, and terms you can live with if something goes wrong. Online retailers can be very useful for value, range and convenience, but the buyer has to do more checking than they would in a shop.
For lens index choices, compare the whole route: prescription entry, measurements, frame suitability, lens upgrades, production time, delivery and aftercare. If the order involves a stronger prescription, varifocals, a new lens type, prescription sunglasses, reglazing or an unfamiliar frame shape, give more weight to support and remake wording than to the biggest discount badge.
A good comparison also separates personal preference from risk. Style, brand and colour are preference decisions. Prescription limits, fitting height, lens index, returns and the ability to fix a problem are risk decisions. The safer retailer is the one that explains the risk clearly enough for you to decide before checkout.
Scenario: choosing between 1.6, 1.67 and 1.74
Imagine a buyer has a valid prescription and has found a frame that looks good in photos. One retailer shows a low headline price, another has better explanations of lens options, and a third offers store or support backup. The right choice depends on what could go wrong. If the prescription is simple and the frame size matches an old pair, the low-cost route may be reasonable. If the prescription is strong, the order is a first varifocal, or the frame is valuable, the buyer should slow down and compare service detail first.
This is why UK Glasses Guide links between retailer reviews and lens guides. The retailer page tells you what the shop appears to be good for. The guide page tells you what to check for your own order. Use both before treating a discount as a decision.
1.6, 1.67 and 1.74 comparison table
| 1.6 index | Often a moderate thinning option for lower to mid prescriptions. |
|---|---|
| 1.67 index | Common for stronger prescriptions where thinner lenses may be useful. |
| 1.74 index | A thinner premium option for some high prescriptions, usually at higher cost. |
How to choose thinner lenses without overpaying
Use this page to make the first decision, then confirm the retailer and lens details before paying. The practical sequence is simple: choose the safest route for the job, build the finished basket, then check delivery and returns. That final service check is where many online orders become clearer, because delivery timing, remake support and returns wording can matter as much as the first quoted price.
If two retailers look similar, choose the one that explains the lens or fitting question more clearly for your situation. A buyer with a simple spare-pair order may reasonably optimise for price and delivery. A buyer dealing with stronger prescriptions, varifocals, sunglasses for driving, reglazing or uncertain measurements should give more weight to support, fitting guidance and the ability to resolve a problem after the glasses arrive.
Lens index mistakes to avoid
- Comparing frame prices without adding the same lens package, delivery and upgrades.
- Choosing a frame shape that works against the prescription or lens type.
- Assuming all prescription orders can be returned like ordinary fashion items.
- Entering prescription, PD, cylinder or axis values without checking every plus, minus and number.
- Using a guide as optical advice instead of speaking to a qualified optician when the order is complex.
Lens index ordering checklist
- Use a current prescription and copy it exactly as written.
- Compare the same lens type, coating, thinning and delivery route across retailers.
- Read delivery, returns, remake and cancellation wording before payment.
- Check whether the frame size and lens depth suit the prescription.
- Keep screenshots or receipts for the final basket and terms you relied on.
Lens index FAQs
Does a higher lens index improve vision?
No. It can reduce thickness and weight for some prescriptions, but it does not make the prescription itself stronger.
Is 1.74 always worth it?
No. It is usually more expensive and may not be necessary for every prescription or frame.
Do thin lenses still need coatings?
Many high-index lenses are paired with anti-reflection coatings because reflections can be more noticeable. Check the retailer package.
Does frame size affect thickness?
Yes. Large frames can make edge thickness more obvious, especially for minus prescriptions.
How do I compare lens upgrades?
Compare the same frame and prescription with each upgrade, then look at cost, coating inclusion and retailer advice.
Medical and fitting advice limits
This page is general buyer information for UK shoppers. It is not medical, optical or prescribing advice. If your prescription is complex, your eyesight has changed, you need children's glasses, or you are unsure about measurements or suitability, speak to a qualified optician before ordering online.
Sources checked
This page uses public retailer and eye-care information as factual grounding, then rewrites the guidance into original buyer-first copy. Retailer prices, availability, delivery terms and return terms can change.