Quick answer
Lens thinning is about lens index. A higher-index lens bends light more efficiently, so the lens can often be made thinner for the same prescription. 1.67 lenses are commonly offered for stronger prescriptions where standard lenses may look thick or feel heavy.
That does not mean every buyer needs 1.67. The right choice depends on prescription strength, frame size, frame shape, lens type, budget and whether the retailer explains the trade-off clearly.
Moderate to strong prescriptions, larger lenses, rimless or semi-rimless frames, and buyers sensitive to lens thickness.
Low prescriptions, small round frames or spare pairs where standard lenses are already acceptable.
Ask whether frame size and prescription justify the upgrade, not just whether it is available.
Why frame size matters
Large frames can make lenses thicker at the edge for minus prescriptions. Choosing a smaller, rounder frame can sometimes reduce thickness more cost-effectively than paying for the highest lens index.
What to compare online
- Whether the retailer recommends lens index by prescription strength.
- How much the upgrade adds to the basket.
- Whether coatings are included or separate.
- Whether the frame is suitable for thinner lenses.
| Standard lens | Often fine for low prescriptions and backup pairs. |
|---|---|
| 1.60 index | A common first thinning step for moderate prescriptions. |
| 1.67 index | Often considered for stronger prescriptions or cosmetic thickness concerns. |
| 1.74 index | Usually a more premium option for higher prescriptions, if available and suitable. |
When to get advice
If your prescription is strong, you are buying varifocals, or you are choosing a very large frame, it is worth asking the retailer or an optician before paying. Lens thinning is useful when matched to the right frame, but it is not a universal upgrade.
Compare before ordering
Use this guide with the retailer comparison and checkout checklist so the final basket, support route and return terms are clear.
Sources checked
This page is written as buyer information, not optical advice. Check current retailer terms and speak to a qualified optician if your prescription, eye health or fitting needs are complex.