Ready-Made Reading Glasses: What They Correct, and What They Ignore

Around forty, the restaurant menu starts backing away on its own. You stretch your arm, you hunt for light, and one day you buy a pair of readers by the till. They help. They also have three blind spots worth knowing about.

Those ready-made pairs, sold in pharmacies, supermarkets or off a petrol-station rack, are neither a trap nor a bad idea. They cope well, within a precise perimeter. The trouble starts when they become the only pair, worn several hours a day for years. Here is what we look at, and why.

Presbyopia, in one sentence

Inside the eye, a flexible lens called the crystalline lens changes shape to focus up close. That is accommodation. Over the years it hardens and deforms less. Distance vision stays as it was, but the near point drifts further away, centimetre by centimetre.

It is a normal process. It moves slowly, and it does not arrive at the same age for everyone: sooner if you are long-sighted, later if you are short-sighted and can simply take your glasses off to read. As an order of magnitude, reading power lands around +1.00 to +1.50 at 45, +1.75 to +2.00 at 50, +2.00 to +2.25 at 55, and it plateaus around +2.50 by 65. Past +2.50 you are not seeing better, you are only holding the page closer. It has nothing to do with myopia or hyperopia, and it adds to them rather than replacing them. A short-sighted presbyope stays short-sighted: they simply take their glasses off to read, until the day that stops working too. We cover the difference between all of them in myopia, hyperopia, astigmatism and presbyopia explained.

What a ready-made pair gets right

Let us be fair. A pre-assembled pair is a real solution in several situations.

• The stopgap. Your pair is at the optician for a repair, you are travelling, you snapped a temple the night before a flight.
• Occasional use. One pair in the kitchen, one in the car, one in the beach bag. Losing a spare pair costs less than losing yours.
• The test. They let you confirm the problem really is near vision, before booking an appointment.

For occasional reading, a few minutes a day, they do the work. No serious optician will tell you otherwise.

What it cannot do: three blind spots

1. Your two eyes are treated as if they were identical

A pre-assembled pair carries the same power right and left. Yet having two slightly different eyes is very common. When that gap exists, the brain compensates constantly to fuse the two images. That invisible work gets paid for at the end of the day, as fatigue or a diffuse headache.

2. Astigmatism is ignored

Astigmatism comes from a cornea curved more in one direction than in the other, a rugby ball rather than a football, so light no longer meets at a single point. It distorts outlines, near and far, and part of it can come from the crystalline lens itself. A pre-assembled pair never corrects it, whatever power you pick. So you can magnify the text without ever making it sharp, and wrongly conclude you need more power.

One precision, because it matters: we measure astigmatism through your correction, on the phoroptor. The curvature and the surface of the cornea themselves are examined by an ophthalmologist, not by us.

3. The optical centres are not placed for you

Every lens has an optical centre, the point where light passes through without deviating. On a pair made for you, the optician places that centre in front of your pupil. On a pre-assembled pair, it sits at an average. If your eyes are closer together or further apart than that average, you are looking slightly off-centre, and the lens deviates the light: that is prismatic effect. It is directly proportional to the power of the lens, so on a weak reading power a small centring error is harmless. It is on the stronger additions that it starts to be felt, and that is exactly the pulling sensation so many wearers describe by the end of a page.

The signals that say readers are no longer enough

None of these signs is serious on its own. Together they say the same thing: your eyes are working too hard.

• You have to increase the power every six months, when presbyopia moves slowly. A new correction will help, but a change that fast also deserves an ophthalmologist's opinion.
• You get a headache after an hour of reading or screen time.
• One eye sees clearly better than the other through the same pair.
• Looking up feels wrong: the floor seems domed or too close.
• You have presbyopia on top of a distance correction, and you juggle two pairs all day.

In that last case especially, a single progressive or intermediate pair often settles it in one go. We explain how they work in progressive lenses explained.

One last reason to have it checked rather than to buy stronger readers. From forty onwards, an eye exam is also when glaucoma or the early eye damage of diabetes gets picked up, and both steal sight for years before you notice anything. Between forty and fifty-five, every two to four years is the accepted rhythm; after sixty-five, every one to two years. That screening is an ophthalmologist's job, not ours, and we will tell you when it is time to go.

What changes when the pair is made for you

A reading pair made for you starts from three measurements: the correction for each eye, taken on the autorefractor then checked by hand one eye at a time, your pupillary distance, and the height at which your eyes sit inside the frame you have chosen. Count twenty to thirty minutes. If you want to know how to read what is written on your prescription, we decoded it in understanding your glasses prescription.

What you gain is not spectacular at first glance. It is more of an absence: you stop thinking about your eyes. The text is sharp from the first second, long reading costs you nothing, and you lose that reflex of taking your glasses off to rest.

And since a reading pair sits on your face several hours a day, it may as well look like you. It is a frame too, not only a device.

A good reading pair goes unnoticed. That is how you recognise one.

If you have had a stopgap pair in a drawer for two years, keep it for the kitchen. And come and have your near vision checked: an optometrist in Canggu, Ubud or Sanur, twenty to thirty minutes. Most of the time that tiredness you had ended up calling normal comes from a correction that no longer fits. When it does not, we say so, and we send you to an ophthalmologist.

The check costs nothing and commits you to nothing: you can walk out with the numbers and think about it. If you do order, a simple single-vision pair is often ready the same day, and progressives take seven to ten days. Leaving Bali before yours is finished is not a problem either, we ship worldwide.

This article is informative and does not replace an eye examination or medical advice. A rapid drop in vision, flashes of light, spots in the visual field or persistent headaches should lead you to consult a health professional without delay.