How strong a prescription do smart glasses take?

The published limit is not the whole story

Three things move the number you can actually order:

1. The arithmetic. Where a maker publishes a total-power limit, your cylinder is added to your sphere first. A -4.00 total-power limit is a -3.00 sphere limit for someone with a -1.00 cylinder.
2. The route. The widest figure often belongs to one route only — an optician partner, or a lens index you have to pay up for. A different route through the same maker can be narrower, and the checker tests each separately.
3. The country. A route published for one market is not automatically offered in another, so the same model can be within range in the US and have no route at all in the UK.

Where no limit is published

An unpublished limit is recorded as unpublished. It is never treated as unlimited, and it is never filled in from a review or a forum post. Where a maker has said nothing, the result says "range not published" and links to what we did find, so you can take it to a dispensing optician rather than guess.

Related: cylinder and astigmatism limits, varifocal support, and the source and freshness rules behind every figure.

This tool compares your prescription with published manufacturer or lens-provider ranges. It is not optical advice and does not replace a dispensing optician. Use a current prescription and ask your dispensing practitioner to confirm the applicable prescription-age and supervision requirements. In the UK, prescription spectacles for anyone under 16, or registered sight impaired or severely sight impaired, must be supplied by or under the supervision of a registered practitioner.