Prescription spectacles and lens types

One lens will not carry you through the whole day

A varifocal is a lens for moving about the world: distance at the top, arm’s length in the middle, reading at the bottom, down a narrow corridor you have to aim at with your chin. For crossing the road, shopping and driving, it is the answer.

Sat at a desk, that corridor runs out. An occupational lens widens the intermediate and near zones at the cost of distance vision, which you do not need in front of a screen anyway. Your head stays level and your neck stops complaining by mid-afternoon.

Plenty of people need both, and saying so sounds like selling twice. The genuinely expensive outcome is a pair of varifocals worn eight hours a day at a computer and then abandoned.

Glazing is the half nobody looks at

The same lens, in the same frame, set a millimetre higher, is a different pair of spectacles. We measure where your pupil falls with the frame already on your face and adjusted, not from a standard table, because the height shifts with how it sits on your nose and ears.

That is why varifocals bought online go wrong more often than the adverts admit. The lens is not worse. There was simply nobody in front of you to measure your face in that particular frame.

Coatings: which ones actually change anything

Anti-reflection is the one you notice, and you notice it most driving at night: without it, every street lamp and every headlight doubles itself inside your own lens. It is the coating we will not suggest dropping to bring the quote down.

Photochromics, the lenses that darken by themselves, come with a limit worth knowing beforehand. They are triggered by ultraviolet, and a car windscreen filters most of it out. Behind the wheel they darken little or not at all, unless they are a version built specifically for that.

• Anti-reflection: fewer reflections at night, fewer flares in photographs
• Hard coat: a plastic lens scratches on its own without one
• UV filter: colourless, sits inside the lens, darkens nothing
• Photochromic: darkens in sunlight, barely behind a windscreen
• Polarised: for glare off the sea and the tarmac, in sunglasses
• Thinned lens: for strong prescriptions, so the edge does not overrun the rim

The first days in varifocals

Steps look odd at first and the floor seems to rise. That is normal and it passes: your brain has to learn which part of the lens to look through and when, which happens by wearing them all day rather than for an hour at a time.

What is not normal is still feeling swimmy a week later, or having to tip your chin up dramatically to read. That is usually the glazing, and it can be corrected. Come back and we will check it. The spectacles stay our business after you have paid for them.