How to choose reading glasses without an eye test

Ready-made readers are sold in dioptres, from about +1.00 to +3.50. Higher is not better: a stronger lens pulls the point of sharp focus closer to your face and narrows the range over which anything is readable.

Take a newspaper into good daylight, cover one eye and read a full paragraph at your natural reading distance. The correct strength lets you hold the page at a comfortable arm bend, keeps text sharp across a wide band of distances, and produces no tightness behind the eyes. When two strengths both seem fine, take the weaker one.

Single focus is one power across the whole lens. Excellent for sustained reading at a fixed distance, useless the moment you look up, which means the glasses come on and off all day.

Bifocal splits the lens into two zones with a hard line. Optically clean within each zone, but the image jumps as you cross the boundary and there is nothing covering the middle distance where a laptop sits.

Progressive changes power gradually down the lens, so there is no line, no jump and full intermediate coverage. It costs a little more and takes three to ten days to adapt to. If your day involves a phone, a screen and a printed page, this is the one worth paying for.

Some ready-made progressives put zero power at the top so your distance vision is unaffected. Others put half the reading power there, which sharpens desk and table range but softens the far wall. Neither is wrong, but buying the wrong one for your room is the single most common reason people give up on progressives.

A typical acetate reader runs 25 to 32 grams. A rimless design can be under 17. That gap decides whether a pair is worn continuously or left in a drawer, and continuous wear is what makes a good lens design worth having. If a frame leaves marks on your nose after an hour, it has already failed.

Anti-reflective coatings genuinely reduce screen glare and are worth having. Blue-light filtering will not save your retina — the evidence does not support that claim — but it does help with evening screen use and sleep, and it costs nothing when it comes built into a lens you were buying anyway.

Off-the-shelf readers use the same power in both eyes and cannot correct astigmatism. If one eye is clearly worse, if you see double, if the change arrived over weeks rather than years, or if headaches persist with correction, book an eye examination. An eye test also screens for conditions that have no symptoms until they are advanced.