Presbyopia: why reading gets harder in your 40s

The menu at arm's length

It starts quietly. You hold the phone a little further away in the evening. The restaurant is dim and you tilt the menu toward the candle. Threading a needle, reading a medicine label or checking a price tag takes longer than it used to, and by the end of the day your eyes feel tired and you may have a headache.

If you have had good eyesight all your life, this can feel like something going wrong. It is not. The National Eye Institute (NEI) describes presbyopia as a normal part of ageing, and says everyone gets it. The American Academy of Ophthalmology (AAO) says symptoms may begin shortly after age 40; the NEI puts the usual start after 45. Healthify NZ says it usually stops getting worse from about age 60.

The word comes from Greek for "old eye", which is unkind but accurate. What follows is what has changed, what presbyopia is not, and the options, without choosing one for you. Our lenses page lists what we fit.

What has changed inside your eye

Behind the coloured part of your eye sits a clear lens. When you are young it is soft and changes shape easily, bulging to focus on close things and flattening for distance. The AAO explains that after about age 40 the lens becomes more rigid and changes shape less easily, so near objects blur while distance usually stays as it was. The NEI describes the same stiffening and adds that the change cannot be stopped or reversed.

Because the lens keeps stiffening for a while, the reading power you need tends to increase through your 40s and 50s. Healthify NZ notes that reading glasses may need gradual increases in strength over that period, and the AAO notes the lens loses flexibility between about 40 and 60. That is why a pair that worked at 44 may feel weak at 50. It is the lens, not the glasses.

What presbyopia is not

It is easy to confuse with other things, so here is what it is not:

• Not a disease. The NEI classes it as a refractive error, a focusing problem, alongside short-sightedness, long-sightedness and astigmatism. Your eye is healthy; its focusing range has narrowed. Our post on refractive errors explains the family.
• Not the same as long-sightedness. Long-sightedness (hyperopia) is about the shape of the eye and can be present from childhood; the NEI describes it as nearby objects looking blurry because of how the eye focuses light. Presbyopia is about the ageing lens, and it adds itself to whatever you already had, short-sighted, long-sighted or neither.
• Not a sign your eyes are weakening from use. The AAO says reading glasses do not make your sight worsen faster, and there is no benefit in putting them off. Squinting through it just adds strain and headaches.
• Not sudden, and not one-sided. Presbyopia creeps in over years. A change that arrives over days, or in one eye only, is a different problem; see the section below.

The options, side by side

The AAO and NEI list the same set of options, and none is right for everyone. Reading glasses are the simplest: the AAO notes they can be bought without a prescription, but the right power should be set by an eye exam, and they only work if presbyopia is your only focusing problem. Bifocals carry a reading segment below a distance zone, usually with a visible line. Progressive lenses change power gradually from distance to near with no line. Occupational lenses are tuned to desk and screen distances. Our guide to single vision vs progressive lenses compares them in detail.

Contact lens wearers have two routes the AAO describes: monovision, where one eye is set for distance and the other for near, which some people find affects judging distance and speed; and multifocal contact lenses, which may be a little less sharp than a single-focus lens. Eye drops that shrink the pupil to help near focus exist in some countries; ask our optometrists what is available in New Zealand rather than relying on overseas pages. Surgical options are a conversation with an ophthalmologist, not something we do.

The table below sums up who each option tends to suit. Lens design, any thinning, and coatings are each priced separately on our spectacles pricing page, and we confirm the total before ordering.

Why an eye exam at this age matters

Buying readers at the pharmacy is fine for many people, but the age when reading gets harder is also the age when some serious conditions begin, and they start silently. Glaucoma NZ recommends a first glaucoma examination by age 45 for people with no symptoms, repeated every 5 years if normal, and earlier or more often with a family history, steroid use, or Asian or African descent. It stresses that glaucoma cannot be self-detected, because the other eye fills in the gaps.

Healthify NZ lists what else becomes more common from here: cataract, macular degeneration, dry eye and, for people with diabetes, diabetic retinopathy. For a generally well adult it suggests an eye test every 2 to 4 years through the 40s to mid 50s, more often later. A comprehensive exam measures your reading power and also checks eye pressure, the optic nerve and the retina; our guide on what an eye exam checks walks through each part, and you can book one on our eye examinations page. No referral is needed in New Zealand.

When this practice is the wrong place

Presbyopia is gradual and affects both eyes in the same way. Healthify NZ advises seeing an optometrist or ophthalmologist straight away for a sudden change in vision, such as distortion or reduced near or central vision. If reading has become hard in one eye over days or weeks, if straight lines look bent, or if a patch of the page is missing, do not wait for a routine slot: book a same-week appointment with us, or see your GP, and say that the change was sudden.

Call 111 or go to the nearest hospital emergency department, rather than booking an optometry appointment, 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.

What happens next

If reading has simply drifted out of reach, you do not need anything urgent and you may not need anything expensive. An eye exam will give you an accurate reading power, rule out the silent conditions, and tell you whether readers, progressives, occupational lenses or contact lenses fit the way you spend your day. Then read the comparison guide, come in and try frames, and decide at your own pace.