Single vision, bifocal, occupational or progressive: which lens suits you

Two pairs on the desk, or one pair that does it all

You are at the point where one pair is no longer enough. Perhaps you swap your distance glasses for readers twenty times a day and keep losing one of them. Perhaps you have just been told you have presbyopia and someone has mentioned progressives, and the word sounds expensive. Or you spend eight hours at a screen and your current pair makes you crane your neck.

Lens design is the decision that follows the prescription, and it is the one that changes how your day feels. This guide compares the four designs we fit most, using the American Academy of Ophthalmology's descriptions and the American Optometric Association's advice on screen work. If you are not yet sure why reading has become harder, start with our guide to what presbyopia is.

What each lens actually does

The American Academy of Ophthalmology (AAO) describes them this way:

• Single vision. One focusing power across the whole lens, for either near or far. Distance glasses for short-sightedness, and reading glasses, are both single vision. Simple, wide, and the easiest to get used to.
• Bifocal. A reading segment in the lower part of the lens and distance correction above it, separated by a visible line. The AAO notes that the line brings an image jump, where things change clarity and position as your eyes cross it.
• Progressive. Distance at the upper part, reading at the lower part, and a smooth change between them with no line. The AAO says the focus areas are smaller and can cause more distortion than other designs, enough that they are hard to wear for about 10% of people.
• Occupational (computer) lenses. A multifocal design that gives more of the lens to screen and desk distances, which the AAO puts at roughly 50 to 65 centimetres from your face. They can reduce strain and make it easier to shift focus around a desk or meeting room, but they are not made for the road.

Getting used to progressives

This is where most doubts sit. The AAO's pros and cons of progressive lenses says adjustment takes anywhere between a week and a couple of months. During that time you may notice distortion at the edges when you move your eyes sideways, feel off balance, or find stairs odd because looking down through the reading zone makes your feet seem larger.

The AAO's tips are practical: have the lenses fitted by an optometrist rather than bought off the shelf, wear them as often as you can, and point your nose at what you want to see and then lift or drop your chin until it is clear. If you get a headache, take them off, rest, and try again later. Our post on progressive lenses for short-sighted people covers the same ground from the wearer's side.

A wider reading area reduces distortion, and the AAO advises not skimping on multifocal lenses for that reason. Our lenses page explains the progressive designs we fit. If you have tried progressives before and could not adapt, say so; bifocals or two single vision pairs are honest alternatives, not a step backwards.

Driving, screens and the shape of your day

Driving. You need a clear distance zone, which single vision distance lenses, bifocals and progressives all give; reading and occupational lenses do not. The AAO notes that an anti-reflective coating cuts glare and is especially helpful for night driving, and that photochromic lenses that darken in sunlight do not work well inside a car because the windscreen blocks the light that triggers them. NZTA (Waka Kotahi) sets the eyesight requirement for a New Zealand driver licence; check its current eyesight page, and tell us which pair you drive in so the prescription suits it.

Screen work. The American Optometric Association says glasses prescribed for general use may not suit the distance of a screen, that people tilt their heads or lean in to compensate, and that lenses prescribed for computer viewing can help. Healthify NZ adds that an optometrist may prescribe glasses for reading and computer use, and recommends keeping a monitor about an arm's length away. If most of your day is a desk, an occupational pair for work plus a progressive or distance pair for everything else is a common combination. Tinted blue-light coatings are a separate question; our guide to blue-light glasses and the evidence covers it.

Sport and children. The AAO recommends polycarbonate for sport because it resists impact, and for strong prescriptions it describes high-index plastic as the thinner, lighter option. Our post on choosing prescription glasses walks through frame fit and materials.

What drives the price

At NVISION a pair is priced in two parts, the frame and the lenses, and the total is confirmed at the fitting. Within the lens, four things move the figure: the design (single vision, bifocal, occupational or progressive), the material index (thinner for strong prescriptions), any coating beyond the standard anti-reflective and scratch-resistant finish that comes with every pair, and whether we are putting new lenses into your existing frame. The AAO notes that progressives cost significantly more than single vision because they take longer to make.

Every figure is on our spectacles pricing page, and our guide on what affects the cost of eye care and eyewear explains the trade-offs. We do not repeat prices here because they change; the page is the source.

When this practice is the wrong place

A lens change assumes your eyes are healthy and the only thing that has shifted is the prescription. Healthify NZ advises seeing an optometrist or ophthalmologist straight away for a sudden change in vision, such as distortion, or if vision problems persist after a new prescription. Blur that a new pair does not fix is a reason for a full eye examination, not a different lens design.

Call 111 or go to the nearest hospital emergency department, not an optical shop, for sudden loss of vision, a shadow or curtain across your vision, flashes with a sudden shower of new floaters, a chemical splash, a red and painful eye with light sensitivity, or an eye injury. Healthify NZ gives the same advice for sudden severe eye pain or vision loss.

How to decide

Bring your current glasses and be specific about your day: how many hours at a screen, whether you drive at night, whether you read in bed, what sport you play. Our optometrists will put the prescription and the day together and suggest one design, or a pair of them. If you are unsure about progressives, ask about the adaptation period and what happens if you cannot get on with them before you order.